Ketamine Pain Control

Written by: Maren Leibowitz, MD (NUEM ‘23) Edited by: Matt McCauley, MD (NUEM ‘21) Expert Commentary by: Seth Trueger, MD, MPH

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Expert Commentary

Thank you both for your excellent overview of ketamine analgesia. For me, the biggest thing is recognizing it is just not a big deal, and the biggest challenge is people's hesitancy to use it because it seems like a bigger deal than it is.

The main principles I highlight:

It's not hard, basically just give 0.1-0.3 mg/kg (20 mg is a good dose for most people).

The key is to give it in a small bag of saline, eg just mix it in 100ml and hang wide open (over about 20 min). This was demonstrated nicely in by Motov and colleagues (https://pubmed.ncbi.nlm.nih.gov/28283340/) and also resonates with my experience with patients.

This slow infusion minimizes (but does not eliminate) dysphoria/"feeling of unreality" some people get, and a slow hand push just does not do the trick. I also aim for 0.2mg/kg as rounding up can get people in the K-hole which is no fun (this is probably the only exception to my general rule of always use more, not less, anesthesia)

Ideally it's nice to do that dose as a bolus and then the same dose as a drip (eg 20mg over 20 min, followed by 20 mg per hour) but many EDs are unable to do that.

The easy way I think about it: a single does essentially replaces a dose of IV morphine- it does not require any more monitoring or have any increased risk of resp depression etc over morphine; ACEP, SEMPA & ENA have a statement on this. (https://www.acep.org/patient-care/policy-statements/sub-dissociative-dose-ketamine-for-analgesia/) It's just simply not sedation or dissociation (hence the term "sub-dissociative") and I have gotten in the habit of calling it "ketamine analgesia."

Perhaps the biggest downside is that for really severe pain, it works well but sometimes only as it's actively dripping in.

The situations I think about using ketamine analgesia are severe pain with contraindications to opioids (eg a patient with a fracture with a history of OUD who does not want opioids) or patients with severe pain where high doses of opioids are not sufficiently helping (eg malignant fractures, severe burns).

Theoretically we could use SDK all the time but there's a chicken/egg problem: we don't use it much, so people aren't very comfortable (plus some other various institutional/historical discomfort with ketamine in some sectors); also, realistically it doesn't last as long as IV opioids. Ideally I would probably use bolus + drip frequently if there weren't barriers.

Dr. Seth Trueger, MD

Assistant Professor of Emergency Medicine
Northwestern Memorial Hospital

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How To Cite This Post:

[Peer-Reviewed, Web Publication] Leibowitz, M. McMauley, D. (2021, March 29.) Ketamine Pain Control. [NUEM Blog. Expert Commentary by Trueger, S]. Retrieved from http://www.nuemblog.com/blog/ketamine-pain-control.

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SonoPro Tips and Tricks for Acute Cholecystitis

Written by: John Li, MD (NUEM ‘24) Edited by: Amanda Randolph (NUEM ‘21) Expert Commentary by: John Bailitz, MD & Mike Macias, MD

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SonoPro Tips and Tricks

Welcome to the NUEM Sono Pro Tips and Tricks Series where Sono Experts team up to take you scanning from good to great for a problem or procedure!

For those new to the probe, we recommend first reviewing the basics in the incredible FOAMed Introduction to Bedside Ultrasound Book and 5 Minute Sono. Once you’ve got the basics beat, then read on to learn how to start scanning like a Pro!

Point of care right upper quadrant ultrasound has been shown to be a highly sensitive (82-91%), specific (66-95%), cost effective and efficient modality for emergency medicine physicians to quickly and effectively identify biliary pathology [1-5]. But despite its widespread utility, right upper quadrant ultrasound can often be a technically difficult study for the beginner sonographer, as there are multiple factors that can influence its ease of acquisition ranging from patient body habitus to bowel gas shadowing, and sonographer experience has been shown to influence its efficacy [1, 6-7].

Beyond the classic patient with right upper quadrant pain, what other scenarios do Sono-Pros use right upper quadrant ultrasound?

1. Epigastric abdominal pain being “diagnosed” and even over treated as GERD. Pick up the probe in the symptomatic patient taking their PPI, EGD negative, or already treated for H. pylori

2. Unexplained right shoulder or back pain. 

3. Colicky pain in the right flank but no urinary findings of nephrolithiasis. 

4. My gallstones are back! But my gallbladder is gone. Look for choledocholithiasis.

5. Chronically ill elderly or immunosuppressed patients with unexplained fever or sepsis. 

SonoPro Tips - How to scan like a Pro

Always Start Smart: To Fail to Prepare is to Prepare to Fail whether in ED POCUS or ED Thoracotomy.

1. Start with the patient in either the left lateral decubitus position or supine with the bed at approximately 30 degrees.

2. Let the patient know “I’ll be asking you throughout this brief exam to take medium to deep breaths and hold for 5 sec, then automatically breathe out.” 

Still not not getting great views? 

1. Scan between the ribs to use the liver as an acoustic window and avoid bowel gas. Switch to a small footprint phased array probe if needed. 

   • Not sure which intercostal space to use? Try about 7 centimeters to the right of the patient’s xiphoid process!

2. Ask the patient to position their arms above their head to open the intercostal space. 

3. Ask the patients to bend their knees to relax the abdominal muscles.

4. In young, thin patients, the gallbladder may be more anterior and superior-- if you are scanning subcostally, try flattening out the probe even more!

Even a Small Pain in the Neck can be a Big Problem!

1. Don’t forget the neck. There is a reason the gallbladder was so nicely distended and  easy to find. Be sure to scan carefully in two orthogonal planes to pick up subtle stones in the neck of the gallbladder!

   • If there is a lot of nearby bowel gas, tell your tech to look for these stones if your surgeons require a confirmatory comprehensive radiology ultrasound before operating. 

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In this GIF, you can see a long-axis view of the gallbladder. When you are initially looking at the body and the fundus of the gallbladder, there are no clear shadowing stones. However, as the sonographer fans to the neck of the gallbladder, they can visualize multiple stones, which are casting shadows posteriorly. Image courtesy of the POCUS Atlas.

SonoPro Tips - Pro Pick Ups!

1. Is that a stone or is that something else in the gallbladder? Roll the patient and see if the “stone” moves! 

   • If the stone in the fundus or body moves, then it’s more likely a mobile stone. 

   • If it doesn’t move, then consider a polyp or a malignancy. Polyps or malignancies generally are non-shadowing while stones are shadowing!

   • Impacted, “non-mobile” Neck Stone = Big Problem and likely to progress to acute cholecystitis. 

2. What’s causing that shadow?

   • Stones shadow posteriorly. 

   • Edges shadow on the sides. Edge artifact results when ultrasound beams scatter passing by a smooth-walled structure, creating an anechoic stripe that could be confused with true shadowing!

3. What if the entire gallbladder is casting a shadow?

   • Think about a gallbladder FULL of stones! This will cause only the most anterior stones to show up on ultrasound.

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Here, on the right side of the screen you see a cross section of the gallbladder that has a large stone in it-- this is casting a shadow so you do not see the posterior wall of the gallbladder at all. This is called the wall echo sign-- where you will only see the most anterior surface of the stone. Image courtesy of the POCUS Atlas.

4. What are some of those pesky mimics of acute cholecystitis?

• Think about hepatic pathologies! Acute hepatitis can cause a clinical Murphy’s sign. You can also have patients who present similarly when they have a congestive hepatopathy from their CHF. Even cirrhotic patients can present with a tender RUQ!

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Here, you can see a dilated gallbladder with a thickened anterior wall and a small amount of pericholecystic fluid, all of which are consistent with acute cholecystitis. Image courtesy of the POCUS Atlas.

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In this still image, you can see a thickened gallbladder wall (although be sure to measure the anterior wall, as the posterior wall can be thickened due to posterior acoustic enhancement!) and a small amount of pericholecystic fluid.  Image courtesy of the POCUS Atlas.

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Here, you can see a dilated gallbladder with an obstructing stone in the neck of the gallbladder. Image courtesy of the POCUS Atlas.

SonoPro Tips - What the Pro’s Do Next!

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Infographic courtesy of Justin Seltzer, MD

1. If you see nonshadowing masses in the gallbladder:

   • Measure it! If the polyp is >1cm, then there’s a ~50% chance that this could be malignant, so be sure to refer these patients for additional imaging and close follow up. 

2. What if you’re hoping to be really thorough and get a beautiful image of the CBD, but despite your best efforts, you cannot find it?

   • Draw some LFTs! A number of our emergency medicine colleagues, including Becker et. al and Lahham et. al, have done studies on this and it has been shown to be very unlikely that the CBD will be pathologically dilated in the setting of normal LFTs. On the flip side, if the LFTs appear cholestatic in nature, that’s another indication for a right upper quadrant ultrasound! [9-10]

SonoPro Tips - Where to Learn More

Do you want to see more pathologic images that you may see when you are doing a right upper quadrant ultrasound? Be sure to check out The Pocus Atlas by our expert editor Dr. Macias! It’s a great resource that also shows some of the rarer etiologies of gallbladder pathology, such as emphysematous cholecystitis or choledocholithiasis.

If you’re interested in looking at some of the evidence behind the right upper quadrant ultrasound, be sure to check out the evidence atlas here as well!

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Expert Commentary

Thank you to NWEM1 John Li for bringing this great idea for a NUEM Blog Series to life. And another thanks to NUEM Blog Founder Mike Macias for his help on both content and graphics!

This new series is intended to push your Sono skills from just good, to really great. We will not rehash the basics. There are already abundant great resources available that we are truly thankful for and utilize everyday. But instead, we will share SonoPro Tips to help you more quickly master challenging POCUS applications and procedures. 

And there is no place better to start than Acute Cholecystitis. This is a great differentiator between the average and the expert clinician sonographer. As John outlines, start smart by expanding your indications and positioning your patient properly from the get go. Then breath, not you, the patient. Breath and hold again and again to bring the gallbladder and even difficult to discern pathology into clear view. Go beyond getting stones, and work to pick up, and explain other pathologies, as well as the bile ducts when needed.  

Thanks again John and Mike! Looking forward to the next post in this new series...

John Bailitz, MD

Vice Chair for Academics, Department of Emergency Medicine

Professor of Emergency Medicine, Feinberg School of Medicine

Northwestern Memorial Hospital

Michael Macias, MD

Global Ultrasound Director, Emergent Medical Associates

Clinical Ultrasound Director, SoCal MEC Residency Programs

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How To Cite This Post:

[Peer-Reviewed, Web Publication] Li, J. Randolph, A. (20201 Mar 22). SonoPro Tips and Tricks for Acute Cholecystitis. [NUEM Blog. Expert Commentary by Bailitz, J. Macias, M]. Retrieved from http://www.nuemblog.com/blog/sonopro-tips-and-tricks-for-acute-cholecystitis

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References

1. Jain A, Mehta N, Secko M, Schechter J, Papanagnou D, Pandya S, Sinert R. History, Physical Examination, Laboratory Testing, and Emergency Department Ultrasonography for the Diagnosis of Acute Cholecystitis. Acad Emerg Med. 2017 Mar;24(3):281-297. doi: 10.1111/acem.13132. PMID: 27862628.

2. Miller, Adam H., et al. “ED Ultrasound in Hepatobiliary Disease.” The Journal of Emergency Medicine, vol. 30, no. 1, 2006, pp. 69–74., doi:10.1016/j.jemermed.2005.03.017. 

3. Shekarchi B, Hejripour Rafsanjani SZ, Shekar Riz Fomani N, Chahardoli M. Emergency Department Bedside Ultrasonography for Diagnosis of Acute Cholecystitis; a Diagnostic Accuracy Study. Emerg (Tehran). 2018;6(1):e11. Epub 2018 Jan 20. PMID: 29503836; PMCID: PMC5827043.

4. American College of Emergency Physicians: Emergency Ultrasound Imaging Criteria Compendium. Oct. 2014, www.acep.org/globalassets/new-pdfs/policy-statements/emergency-ultrasound-imaging-criteria-compendium.pdf. 

5. Hilsden R, Leeper R, Koichopolos J, et al. Point-of-care biliary ultrasound in the emergency department (BUSED): implications for surgical referral and emergency department wait times. Trauma Surg Acute Care Open. 2018;3(1):e000164. Published 2018 Jul 30. doi:10.1136/tsaco-2018-000164

6. Ma, John, et al. Ma and Mateer's Emergency Ultrasound. McGraw-Hill Education, 2020. 

7. Mallin, Mike, and Matthew Dawson. Introduction to Bedside Ultrasound: Volume 2. Emergency Ultrasound Solutions, 2013. 

8. Macias, Michael. TPA, www.thepocusatlas.com/. 

9. Becker BA, Chin E, Mervis E, Anderson CL, Oshita MH, Fox JC. Emergency biliary sonography: utility of common bile duct measurement in the diagnosis of cholecystitis and choledocholithiasis. J Emerg Med. 2014 Jan;46(1):54-60. doi: 10.1016/j.jemermed.2013.03.024. Epub 2013 Oct 11. PMID: 24126067.

10. Lahham S, Becker BA, Gari A, Bunch S, Alvarado M, Anderson CL, Viquez E, Spann SC, Fox JC. Utility of common bile duct measurement in ED point of care ultrasound: A prospective study. Am J Emerg Med. 2018 Jun;36(6):962-966. doi: 10.1016/j.ajem.2017.10.064. Epub 2017 Nov 20. PMID: 29162442.

Health Risks Imposed by the Beach

Written by: Alex Herndon, MD (NUEM ‘21) Edited by: Ashley Amick, MD, MS (NUEM ‘18) Expert Commentary by: Patrick Lank, MD

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With warm weather fast approaching, it’s time to break out the sunscreen and beach gear. Besides protecting oneself from UV rays and heat exhaustion, there are other dangerous pathogens lurking in the sandy shores that are worth being aware of as patients begin to flood the Emergency Department during summer vacation. Here are a few dangerous diseases to consider that masquerade as common chief complaints.  

1. More than just swimmer’s itch 

A 17 year old female presents to the Emergency Department complaining of a patchy skin rash that developed only a couple days after her first swim of the summer. Freshwater lakes house trematode parasites that upon contact leads to cercarial dermatitis, otherwise known as “swimmer’s itch”. Symptoms typically develop 2 days after exposure and last a week. Relief can be easily obtained with antihistamines and corticosteroid cream. [1]

Now consider that same patient is returning from a trip from Key West, Florida for a Bachelorette Party.  You notice that her legs are shaved and there are several small nicks around her ankles.  She is presenting with a worsening red rash on her lower leg that is red, warm, blistering, and in some locations has formed superficial ulcers. While it can be easy to chalk this us to severe sunburn and possible superimposed cellulitis, it is important not to miss this deadly necrotizing skin infection caused by Vibrio vulnificus, commonly known as one of many “flesh-eating bacteria.” Unlike the more benign trematode, V vulnificus can be found in brackish or saltwater, and in North America most commonly in the Gulf of Mexico. [2] V vulnificus infects wounds and leads to skin breakdown and ulceration and if not treated immediately infection has a mortality rate of anywhere from 25-50%. [3] Given the virulence of the disease, it is important to treat early and aggressively. The mainstay treatment for V vulnificus includes intravenous 3rd generation cephalosporins along with a tetracycline such as doxycycline. Source control becomes prudent and may require surgical debridement. [4]

2. “It’s just a cough”

With the warm weather finally here, a 60 year-old retiree began breaking in his paddle board along the shores of Lake Michigan. To cool off afterwards, he would hit the public beach showers. One week later he shows up at the Emergency Department complaining of body aches, low grade fevers, and a cough that won’t quit. While the bacteria Legionella pneumophila is typically associated with hot tubs, don’t forget other warm freshwater places this microbe loves to grow, including beach showers, air-conditioning units, and outdoor misters like those seen at amusement parks and sporting events. [4] People fall ill after inhaling aerosolized droplets from the contaminated sources.

Pontiac fever is a mild form of Legionella infection, presenting as vague flu-like symptoms that typically resolve in 2 to 4 days without treatment. However, the more severe form of infection, commonly known as Legionnaires disease, presents as pneumonia with cough, fever and myalgias. Unlike other bacterial pneumonias, Legionnaires is also more commonly associated with gastrointestinal symptoms like nausea, vomiting, and diarrhea, and can also cause hyponatremia. On average 15% of cases per year have been fatal, thus never forget to start atypical coverage for pneumonia, such as azithromycin, which provides adequate coverage for Legionella infection. [5]  And if Legionella is diagnosed or highly suspected, alerting local health authorities is important because early containment of possible sources, such as public showers, is imperative to preventing a deadly outbreak.

3. Beyond febrile seizures

A 10 year-old boy is sent to sailing camp in Wisconsin.  While he was well upon arrival, after only 3 days his parents get a call that their son has been hospitalized. His camp counselors brought him to the ED after he became febrile and had a seizure a day after capsizing in the lake. They reported throughout the day the boy had been complaining of a headache and was increasingly lethargic. Typically the constellation fever, headache, altered mental status, and seizure heralds bacterial meningitis. However given this child’s unique summer camp experience, one must consider other environmental exposures that pose a risk. 

While rare, warm freshwater lakes can house the deadly Naegleria fowleri, more commonly known as “the brain-eating amoeba.” [6] This amoeba enters via the swimmer’s olfactory nerve, reaching the brain where it causes primary amebic meningoencephalitis (PAM). Patients present within 1 day to 2 weeks after exposure, first with flu-like symptoms including fever, headache and vomiting, that eventually progress to involve hallucinations and seizures. Similar to any patient presenting with symptoms concerning for meningitis, performing a lumbar puncture is key in making the diagnosis. N fowleri can be identified within cerebral spinal fluid either via direct visualization, antigen detection or PCR. While the majority of cases have been fatal, with a fatality rate of nearly 98%, survival is possible if identified and treated early with miltefosine, an anti-leishmania drug. [7]

During these warm summer months it is vital to understand where your patients have been and what they have been doing because knowing those details can end up saving their lives.

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Expert Commentary

Thank you Drs. Herndon and Amick for these wonderful reminders that there are more things to be afraid of at the beach than sharks (and/or Sharknados). While this blog post contains great tidbits on three diagnoses, I think these cases also highlight times when a careful focused clinical history changes the emergent work-up and treatment. These patients could have easily been diagnosed with another condition and had their definitive care delayed, so thank you for these reminders. 

As a native Floridian who grew up within walking distance of the Atlantic Ocean, I think there are a few additional entities for the emergency physician to consider when treating beachgoers. My medical toxicology training is begging me to direct this commentary towards my wheelhouse, but I will resist and will be sure to mention some other diagnoses. 

But to start, I have to bring up intoxication. For those readers who do not live in the Midwest of the United States, I want to make you aware that Chicago has a wonderful series of beaches. Having been working in an emergency department in Chicago for 15 years now, I also have to point out that the number one reason patients are brought to the ED from a beach is for alcohol intoxication. Higher temperatures, increased thirst, increased physical activity, prolonged drinking, and possible co-ingestion of other mind-altering substances all increase the chances that a day at the beach will end in the ED. So be careful, warn your teenage/twenty-something family members, and consider checking an ethanol concentration in altered beachgoers.

The geographic proximity our ED has to the beach and Lake Michigan also means we see a lot of drownings. Some are intentional, others accidental; some are associated with traumatic injuries, others with intoxication; some patients are pediatric, some are geriatric. Despite their variations, all drowning should be taken seriously and involve aspects of resuscitation that are worth reviewing when you get a chance. Although it is now a few years old, I recommend reading the review article “Drowning” by D Szpilman, et al. from NEJM in 2012 (DOI: 10.1056/NEJMra1013317). It’s a great review with some helpful references for people interested in reading more. 

Finally I would recommend anyone working in a clinical environment where the weather is about to turn warmer should review the clinical features and resuscitation of patients with heat-related injuries and superficial burns. When I was a PGY-1 in Chicago and had my first patient check in with a sunburn, I was in complete shock. Why did this person not know homecare for a sunburn? Easy, I thought: lots of aloe, move like a mummy for a day, and bathe in self-loathing and regret. But years of experience in a northern clime have taught me that changes in seasons are particularly dangerous for these injuries – people are out of practice, they forget, or they simply don’t care. No matter the reason, these early parts of the season are when we see big upticks in significant presentations. 

In summary, thank you again for bringing up these infectious complications of having fun at the beach. But if you want to scare some sense into your 15-year-old nephew, don’t only tell him about Naegleria fowleri – please also terrify him with stories of overdoses, drowning, and severe hyperthermia.

Patrick Lank, MD, MS

Assistant Professor of Emergency Medicine

Medical Toxicologist

Department of Emergency Medicine

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How To Cite This Post:

[Peer-Reviewed, Web Publication] Herndon, A. Amick, A. (2021, Mar 15). Health Risks Imposed by the Beach. [NUEM Blog. Expert Commentary by Lank, P]. Retrieved from http://www.nuemblog.com/blog/health-risks-imposed-by-the-beach.

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Other Posts You May Enjoy

References

1. Parasites: Cercarial Dermatitis. Centers for Disease Control and Prevention. 2012 January. <https://www.cdc.gov/parasites/swimmersitch/faqs.html>

2. Thompson, H. Eight diseases to watch out for at the beach: “Flesh-Eating” bacteria. The Smithsonian. 2014 August. <https://www.smithsonianmag.com/science-nature/diseases-watch-out-beach-18095234 6/>

3. Horseman, M. Surani, S. A comprehensive review of Vibrio vulnificus: an important cause of severe sepsis and skin and soft-tissue infection. Int J Infectious Diseases. 2011 March: 15(3): 157-166. 

4. Thompson, H. Eight diseases to watch out for at the beach: Pontiac Fever and Legionnaires Disease. 2014 August. <https://www.smithsonianmag.com/science-nature/diseases-watch-out-beach-180952346 /#mftUupdDj 5cwE00L.99>

5. Healthy Swimming: Respiratory Infections. Centers for Disease Control and Prevention. 2016 May. <https://www.cdc.gov/healthywater/swimming/swimmers/rwi/respiratory-infections.html>

6. Thompson, H. Eight diseases to watch out for at the beach: “Brain-Eating” Amoeba. The Smithsonian. 2014 August. <https://www.smithsonianmag.com/science-nature/diseases-watch-out-beach-180952346 /#mftUupdDj5cwE00L.99>

7. Parasites: Naegleria fowleri - Primary Amebic Meningoencephalitis - Amebic Encephalitis. Centers for Disease Control and Prevention. 2017 February. <https://www.cdc.gov/parasites/naegleria/pathogen.ht ml> 

Felon

Written by: Daniel Levine, MD (NUEM ‘23) Edited by: Will LaPlant, MD, MPH (NUEM '20) Expert Commentary by: Matt Levine, MD

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Expert Commentary

Thank you for the handy concise reference for felon management. Some key points of emphasis and elaboration:

A TENSE distal finger pad is what distinguishes a felon from other finger infections.  A paronychia can be the portal of entry (as in this case https://www.ortho-teaching.feinberg.northwestern.edu/cases/hand/case14/index.html) . However, a paronychia alone should not cause a TENSE finger pad so check the finger pad before diagnosing a finger infection as a simply a paronychia.  Flexor tenosynovitis is not localized to the distal pad and should be readily distinguishable from a felon, which is localized. Whitlow may be confused for a purulent infection but is cutaneous and again, will not have a TENSE pad.

The felon itself is an intense throbbing pain and the procedure is extensive so analgesia is a major point of emphasis for successful management.

The key to understanding the nature and treatment of a felon is knowledge of the anatomy of the distal finger. There are 15-20 discrete, noncompliant, tough fibrous septae of the finger pad which run from the periosteum to the skin.  The abscess of a felon affects these unforgiving septae, which is why is it so painful.  The incision must enter the septae and the dissection must break up the remaining septae to completely drain the infection.  Other abscesses we drain may have loculations but not the tough septations of a felon.  So the dissection must be firm enough to break these septations. 

There are many different (and interestingly named) incisions that have been described to decompress a felon, like the “hockey stick” (https://lacerationrepair.com/felon-hockey-stick/) or the “fish mouth” (https://lacerationrepair.com/felon-fish-mouth/).  Many sources prefer lateral approaches over volar approaches.  The volar approaches incise directly through the highly innervated pad and residual paresthesia affecting finger function is a concern. 

Be aware that you are dissecting just volar to the phalanx to get into these septae, so this is deep.  If the etiology of the felon is direct extension from a paronychia, drain the paronychia first and see if you can access the felon by dissecting through the paronychia tract.  Afterwards, insert packing or a drain.  I have even seen consultants make bilateral incisions and feed a drain all the way through to facilitate drainage.

Refer all of these patients to hand clinic.  One patient I had who was lost to follow up returned to the ED weeks later with osteomyelitis of the distal phalanx (https://www.ortho-teaching.feinberg.northwestern.edu/cases/bone-lesions/case4/index.html).

Matthew R Levine, MD

Associate Professor of Emergency Medicine

Northwestern Memorial Hospital

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How To Cite This Post:

[Peer-Reviewed, Web Publication] Levine, D. LaPlant, W. (2021, March 8). Felon. [NUEM Blog. Expert Commentary by Levine, M]. Retrieved from http://www.nuemblog.com/blog/felon.

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Paronychia

Written by: Richmond Castillo, MD, MS, MA (NUEM ‘23) Edited by: Andra Farcas, MD (NUEM ‘21) Expert Commentary by: Matthew Kippenhan, MD

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Expert Commentary

While paronychia is commonly seen in Urgent Care and Fast Track settings, this is a condition that some EM residents may not get much exposure to during their training.  Knowledge of minor conditions such as this may not match the excitement of a critically ill patient, but it is an essential skill set for every EM physician. 

The biggest pitfall I have seen in treating paronychia is failure to drain a patient who has a clear fluid collection.  Providers not trained to perform the procedure will often give oral antibiotics as treatment, but once purulence has developed these will be ineffective without drainage.  We tend to see a fair number of patients who have already been on antibiotics but have failed to improve.

If you see a patient without signs of abscess, provide proper instruction above on soaking and topical antibiotic ointment, but be sure to provide anticipatory guidance that it may still worsen and require drainage - just not yet.  Patients appreciate knowing your thought process on why you are providing specific treatment based on their presentation.  

When draining a paronychia, I prefer to use an 11 blade laid flat on the nail to make a small incision, then lifting the skin slightly away from the nail.  While some tolerate the procedure well, I do offer a digital block to alleviate any apprehension.  For those with more extensive involvement, you may place a wick with a short piece of 1/4" iodoform and have the patient remove it in 1-2 days.  Be sure to offer a wound check in 48 hours  - either in the ED or an urgent care if available.  Counsel the patient that the finger will not look completely normal for 1-2 weeks but we want to see a steady improvement over that time.

Although infrequent, patients with diabetes or vascular disease can have further complications, such as an ascending cellulitis, evolution into a deep space infection of the digit, or even osteomyelitis.  While the amount of pain typically drives patients to seek care sooner, patients with certain conditions (ie substance abuse, poor access to care, AMS) may go unrecognized for a longer period leading to more serious infection.  Complicated cases like this should have imaging (xray) and consultation with a hand surgeon.

Matthew Kippenhan, MD

Medical Director, Emergency Department

Northwestern Memorial Hospital

Assistant Professor, Feinberg School of Medicine

Northwestern University

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How To Cite This Post:

[Peer-Reviewed, Web Publication] Castillo, R. Farcas, A. (2021, Mar 1). Paronychia. [NUEM Blog. Expert Commentary by Kippenhan, M]. Retrieved from http://www.nuemblog.com/blog/paronychia.

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Knee Dislocation

Written by: Andrew Rogers, MD, MBA (NUEM ‘22) Edited by: Amanda Randolph, MD (NUEM ‘21) Expert Commentary by: Matt Levine, MD

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Introduction

Tibiofemoral dislocations are a relatively uncommon injury with high risk of morbidity to patients, and therefore represent an injury that the Emergency Physician should familiar with diagnosing and treating.  The incidence of knee dislocation is quite low, representing approximately 0.02% of all orthopedic injuries. [1] Morbidity is high, with rates of vascular injury of 7-40%, neurologic injury of 5-40%, and amputation rates of around 12%. [2,3]  Delays in identifying vascular injury >8 hours can result in higher rate of amputation approaching 86%. [3,4] Timely identification, treatment, and disposition directly impacts patient’s lives and limbs. 

Anatomic Review

The knee is stabilized by ligaments, tendons, muscles, menisci, and cartilage.  Figure 1 highlights key anatomic structures that stabilize the knee joint, including the major ligaments of the ACL, PCL, MCL, and LCL.  These ligaments, in various combinations, are disrupted in knee dislocations.

The neurovascular anatomy is also important to review and understand (Figure 2).  The popliteal artery courses posterior to the joint and is tethered both proximally (at the tendinous hiatus of the adductor magnus) and distally (at the tendinous arch of the soleus muscle), making it susceptible to injury. [2]  The sciatic nerve divides into the tibial and common peroneal nerves proximal to the popliteal fossa, with the common peroneal nerve tethered about the fibular neck. This attachment similarly increases the risk of common peroneal nerve injury. [2]

Figure 1: Structural Anatomy of the Knee [5]

Figure 2: Neurovascular Anatomy of the Knee [6]

Mechanism of injury

The mechanism of a knee dislocation can be high-energy, low-energy, or ultra-low energy. [2] 

• High energy: MVCs, falls from heights, crush injuries –  ~50% of knee dislocations

• Low energy: Sports injuries – ~33% of knee dislocations

• Low energy: Falls from standing - ~10% of knee dislocations

• Ultra-low energy: ADLs in morbidly obese (BMI >40) population [7, 8] 

Classifications of Knee Dislocations

Two main classifications are used to categorize knee dislocations. [2] The Kennedy Classification defines the injury based on the direction of displacement of the tibia relative to the femur (Figure 3)  The Schenck Classification is based on the pattern of ligamentous injury, with the Wascher modifications specifying lateral ligaments ruptured (Figure 4).  

Figure 3: Kennedy Classification of knee dislocations with example illustrations [9]

Figure 4: Schenck Classification System with Wascher Modification [2]

ED Evaluation

Approximately 50% of knee dislocations spontaneously reduce so the Emergency Physician should maintain spontaneously reduced knee dislocation on their differential in all patients presenting with knee pain, especially for the obese patient with an ultra-low energy mechanism. [2, 3] Figure 5 is a summary diagram from Gottlieb, et al summarizing the algorithm for evaluation and management of knee dislocations.

Figure 5: Algorithm for the evaluation and management of knee dislocations in the Emergency Department [10]

History

Some historical details to inquire about include:

• Mechanism of injury

• Sensation of instability

• Deformity at any point in time

• History of injury or surgery to the joint

• Timing of injury

Initial Physical Exam

As 50% of dislocations spontaneously reduce or due to an obese patient population, there may not be an obvious physical deformity.  Key points to include (and document) on the physical exam include: [3, 10]

• Gross deformity

• Vascular exam

  • Assess for presence of dorsalis pedis and posterior tibialis pulses

  • Look for hard signs of vascular injury: pallor, coolness, pulsatile hematoma, pulsatile hemorrhage, palpable thrill, audible bruit, absent or diminished pulses

• Neurologic exam

  • Sensory and motor deficits

  • Signs of common peroneal nerve injury:

    • Sensory deficit to lateral leg and dorsal foot

    • Inability or weakness in eversion and dorsiflexion of foot

• Skin exam

  • Look for pinched, discolored, tented, or threatened skin

  • Assess for open dislocation or fracture

  • Bruising without effusion suggests capsule disruption – may hint toward dislocation [11]

• Ligamentous laxity

  • May be limited by pain, effusion, or deformity

• Compartments exam

 In high-energy mechanisms, consider other injuries as a knee dislocation may be distracting, or consider careful examination of the knee if other injuries limit history (for example a head injury sustained in an MVC).

Initial imaging

• AP and lateral radiographs of the knee

• Recommended to also obtain radiographs of femur, tibia and fibula, as well as ankle and hip joints, although additional radiographs should not delay closed reduction if indicated, and may be obtained after reduction of the knee [11]

• If patient cannot tolerate plain films, can consider urgent CT

• Assess for dislocation and fractures (Figure 6)

• Some subtle signs of spontaneously reduced knee dislocation include: [11]

  • Widening of medial joint space on AP film

  • Segond fracture – avulsion fracture of lateral tibial plateau which is frequently associated with ACL disruption (Figure 7)

  • Fibular head avulsion fracture (AKA arcuate fracture) – avulsion of LCL or arcuate ligament complex (Figure 7)

Figure 6: Lateral knee dislocation [12]

Figure 6: Posterior knee dislocation [13]

Figure 7: Segond fracture with red circle showing lateral tibial plateau avulsion fracture [14]

FIgure 7: Fibular head avulsion fracture with white arrow showing avulsed fragment [15]

Reduction

Once the diagnosis of knee dislocation is made, reduction should be attempted in the Emergency Department under adequate analgesia and conscious sedation. Early orthopedics consultation is recommended. Reduction technique requires at least two team members to perform, and involves reversing the mechanism of injury (Figure 8). [3, 10] One team member stabilizes the distal femur while the other team member provides in-line traction on the lower leg. If this is unsuccessful, then apply anterior or posterior pressure to the proximal tibia and/or distal femur with in-line traction still applied to facilitate relocation. Avoid applying pressure to the popliteal fossa, which may cause or worsen neurovascular injury. Some knee dislocations may not be reducible in the Emergency Department and may require open reduction by orthopedics in the operating room. 

Figure 8: Technique for reduction of knee dislocation [20]

Post reduction

After successful reduction, splint in 20 degrees of flexion and/or use a knee immobilizer to stabilize the joint. [3, 10] Cut out windows in the splint to perform regular neurovascular checks. Prior to splint placement, consider full ligamentous examination while the patient is under conscious sedation prior to splinting to assess ligamentous injury. 

Repeat evaluation of neurovascular status is imperative. Evaluation of peripheral pulses is key, but normal pulses may not rule out vascular injury due to collateral flow about the knee. [16, 17] An Ankle-Brachial Index (ABI) should be obtained in all patients (Figure 9). An ABI is <0.9 has been shown to be 100% sensitive for vascular injury requiring operative repair. [3] Patients with an ABI >0.9 still require close monitoring and repeat exams.

Figure 9: Ankle brachial Index [18]

Some authors advocate for angiography in all knee dislocations while others advocate for angiography only in those with an abnormal ABI. [3, 17, 19] Given the time-sensitivity of a vascular injury threatening the limb, early consultation with vascular surgery in patients with concern for vascular injury is recommended.  Vessel imaging should never delay operative intervention if indicated. [3]

Options for vessel imaging include:

• CTA – quick and readily available in the ED with high sensitivity (95-100%) and specificity (99.7-100%) [10]

• Direct or selective angiography – considered standard of care but is invasive and introduces risks of vessel cannulation.

• Duplex ultrasonography – has good sensitivity (95-100%) and specificity (97-100%) but is operator dependent, may miss small intimal injuries, and availability may be limited. [10]

Disposition

Emergency surgery is indicated for:

• Open dislocation

• Irreducible dislocation

• Ischemic limb

• Vascular injury

• Compartment syndrome

All patients not taken to the operating room for emergent exploration should be admitted for at least 24 hours of neurovascular and compartment checks. [3,10] The knee should be immobilized as described above, with the leg made non-weight bearing. If evidence of common peroneal nerve injury, will need ankle-foot orthotics and physical therapy. Nearly all knee dislocations will require eventual reconstruction 2-3 weeks post-injury with nerve exploration and repair as indicated at that time. [19]

Summary and Key Points

• Knee dislocations are rare but significant injuries that require time-sensitive diagnosis and management.

• There is high morbidity, with up to 40% vascular and/or nerve injury, and up to 10% leading to amputation.

• Consider early consultation with orthopedic surgery and vascular surgery, as appropriate

• Early closed reduction in the Emergency Department is key, with appropriate post-reduction immobilization

• The neurovascular exam is critical, both pre- and post-reduction

• All patients should have an ABI check post-reduction, regardless of the presence of a pulse, with vessel imaging pursued in those with abnormal ABI

• All patients require admission for neurovascular and compartment checks

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Expert Commentary

Thank you, Dr. Rogers, for providing an excellent comprehensive review of knee dislocations. Over the course of my career in the last 20+ years, imaging workup for knee dislocations has evolved substantially.  It used to be dogma that all knee dislocations get traditional IR angiography.  This was based on reports of undiagnosed popliteal artery thrombosis, where patients presented with a clinically and radiographically reduced knee and a palpable dorsalis pedis pulse that progressed to ischemic compartment syndrome and amputation. This paradigm has shifted because:

• More recent studies indicate that the true incidence of popliteal artery injury is 7.5-14%. This is lower than initial older data suggested. [1, 2, 3]

• The vast majority of intimal tears do not progress

• CT angiography has emerged as a less invasive and highly sensitive option.

• Emerging data have shown that observation periods for serial pulse checks and ABIs are highly sensitive for detecting clinically significant vascular lesions.

Remember that the first priorities in knee dislocations are rapid diagnosis and reduction. Reduction can restore absent pulses.  Remember the algorithm provided by Dr. Rogers depends on what the vascular exam is AFTER reduction, not before.

Time sensitivity for those cases with vascular deficits cannot be emphasized enough. Delay dramatically affects outcome. Residual amputation rates post-surgery are 10%. [1] In cases of delay exceeding 8 hours, amputation rates have been reported to reach as high as 86%. [4] If required, on-table angiography in the operating theatre, rather than in radiology, has been reported to save 3 hours. [5, 6] So patients with ischemia/pulselessness after reduction need to be taken emergently to the OR, not to the CT suite.

Magnetic resonance (MR) angiography has been proposed as an alternative to define the vascular anatomy and diagnose asymptomatic vascular lesions, particularly as all these patients are likely to have MRI at some point to define the extent of ligamentous injury. In a small series of knee dislocations, findings were comparable to traditional angiography. Consider advocating for this when your consultant suggests CTA for patients with normal vascular exams and ABIs.

References:

1. Boisrenoult P, Lustig S, Bonneviale P, et al. Vascular lesions associated with bicruciate and knee dislocation ligamentous injury  Rev Chir Orthop Traumatol, 9 (2009), 621-626.

2. Harner CD, Waltrip RL, Bennett CH, et al. Surgical management of knee dislocations  J Bone Joint Surg Am, 86 (2004), 262-273.

3. Rios A, Villa A, Fahandezh H, et al. Results after treatment of traumatic knee dislocations: a report of 26 cases  J Trauma, 5 (2003), 489-494.

4. Green NE, Allen BL. Vascular injuries associated with dislocation of the knee  J Bone Joint Surg Am, 5 (1977), 236-239.

5. Lim LT, Michuda MS, Flanigan DP, Pankovich A.  Popliteal artery trauma 31 consecutive cases without amputation  Arch Surg, 11 (1980), 1307-1313.

6. Ottolenghi CE.  Vascular complications in injuries about the knee joint  Clin Orthop Relat Res (1982), 148-156.

Matthew R Levine, MD

Associate Professor of Emergency Medicine

Northwestern Memorial Hospital

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How To Cite This Post:

[Peer-Reviewed, Web Publication] Rogers, A. Randolph, A. (2021, Feb 22). Knee Dislocation. [NUEM Blog. Expert Commentary by Levine, M]. Retrieved from http://www.nuemblog.com/blog/knee-dislocation.

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Other Posts You May Enjoy

References

1. Rihn, et al. “The acutely dislocated knee: Evaluation and management.” Journal of the American Academy of Orthopaedic Surgeons. 2004;12(5):334-346

2. Medina, et al. “Vascular and Nerve Injury After Knee Dislocation: A Systematic Review.” Clinical Orthopaedics and Related Research. September 2014. 472 (9): 2621-2629.

3. Boyce, et al. “Acute Management of Traumatic Knee Dislocations for the Generalist.” Journal of the American Academy of Orthopaedic Surgeons.” December 2015. 23(12):761-768

4. Patterson et al. “LEAP Study Group: Knee dislocations with vascular injury: Outcomes in the Lower Extremity Assessment Project (LEAP) Study.” Journal of Trauma 2007;63(4):855-858

5. “Knee Diagram.” Wikimedia Commons. https://commons.wikimedia.org/wiki/File:Knee_diagram.svg

6. Morcos, et al. “Popliteal lymph node dissection for metastatic squamous cell carcinoma: A case report of an uncommon procedure for an uncommon presentation.” World Journal of surgical Oncology. October 2011. 9(1):130

7. Azar, et al. “Ultra-Low Velocity Knee Dislocations.” American Journal of Sports Medicine. October 2011. 29(10):2170-4.

8. Vaidya, et al. “Low-Velocity Knee Dislocations in Obese and Morbidly Obese Patients” Orthopaedic Journal of Sports Medicine. April 2015. 3(4).

9. Lasanianos, et al. “Knee Dislocations”. Trauma and Orthopaedic Classifications. Springer-Verlag London 2015. pp339-341.

10. Gottleib et al. “Evaluation and Management of Knee Dislocation in the Emergency Department.” The Journal of Emergency Medicine. November 2019. 58(1) 34-42.

11. Lachman, et al. “Traumatic Knee Dislocations: Evaluation, Management, and Surgical Treatment.” Orthopedic Clinics of North America. October 2015. 46{(4):479-93

12. Murphy, Andrew. “Lateral Knee Dislocation”. Wikimedia Commons. 20 May 2017. https://commons.wikimedia.org/wiki/File:Lateral-knee-dislocation-1.jpg

13. Duprey K and Lin M. “Posterior Knee Dislocation”. Wikimedia Commons. 2 February 2010. https://commons.wikimedia.org/wiki/File:PosteriorKneeDIsclocation.jpg

14. Ellisbjohns “Segond Fracture”. Wikimedia Commons. 2 November 2009. https://commons.wikimedia.org/wiki/File:SegondFracture.JPG

15. Thrush, et al. “Fractures Associated with Knee Ligamentous Injury.” Complex Knee Ligament Injuries, pp149-159. January 2019.

16. McDonough, E. and Wojtys E. “Multiligamentous injuries of the knee and associated vascular injuries”. American Journal of Sports Medicine. January 2009, 37 (1):156-9

17. Barnes et al. “Does the pulse examination in patients with traumatic knee dislocation predict a surgical arterial injury? A meta-analysis.” Journal of Trauma; Injury, Infection, and Critical Care. December 2002. 53(6):1109-14.

18. Jmarchn. “Ankle-Brachial Index” Wikimedia Commons. 14 February 2014.https://commons.wikimedia.org/wiki/File:Pad_abi_ENG.svg

19. Fanelli, Gregory C. “”Knee Dislocation and Multiple Ligament Injuries of the Knee.” Sports Medicine and Arthroscopy Review. December 2018. Issue: Volume 26(4), p150-152.

20. Henretig, et al. “Textbook of Pediatric Emergency Procedures. Philadelphia, PA: Williams & Wilkins. 1997. P1098. https://aneskey.com/knee-dislocation-and-reduction/

What to expect when you're expecting a concussion

Written by: Kelsey Green, MD (NUEM ‘23) Edited by: Jordan Maivelett, MD (NUEM ‘20) Expert Commentary by: Jake Stelter, MD

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Expert Commentary

This is a great review of anticipatory guidance when counseling patients who have been diagnosed with a concussion.  As noted, “mild traumatic brain injury (mTBI)” is often used synonymously with “concussion.” A better way to conceptualize this is to view concussion as a form of mTBI, realizing that mTBI can represent a spectrum of conditions.  One of the most important treatments of concussion from the Emergency Department (ED) perspective is to counsel patients on what to expect and how to best control their symptoms.  Concussions can present with a wide range of symptoms as detailed and can be quite distressing and disruptive to patients. As correctly pointed out, the presence of vestibular symptoms (i.e. dizziness or gait instability) as well as pre-existing mental health diagnoses, such as depression or anxiety, are associated with a protracted symptom course. Setting expectations of the symptoms they may develop and the possible timeline of symptom duration is important for patients as they manage their condition.  Early conservative treatment with adequate sleep and relative cognitive and physical rest will help manage and reduce the intensity of symptoms.  In our current society, it is nearly impossible to completely avoid screens and reading.  Hence, “everything in moderation” is appropriate when counseling these patients.  If the patient has to work at a computer, advise them to take frequent breaks for at least 10 minutes for every 30 minutes of screen time.  In addition, it is recommended that patients with a concussion avoid alcohol.  It is also advisable to avoid excessive caffeine.  However, if a patient already uses caffeine on a daily basis, they should not stop completely, as that can lead to withdrawal headaches.  Over-the-counter pain relievers, such as naproxen, ibuprofen or acetaminophen are appropriate for headache treatment, provided there are no contraindications to use.

 There are multiple return-to-learn, -work and -play protocols that have been published.  This is particularly applicable to athletes who have sustained a sport-related concussion (SRC).  Most schools and athletic programs have protocols that have been developed in conjunction with athletic trainers and team physicians.  It is important to remember that as an ED provider, you should not clear a patient to return to play.  That process needs to be conducted by the school athletic trainer in collaboration with the team physician after they have had the opportunity to evaluate the patient. You should consider referring your concussion patients to a Primary Care Sports Medicine or Neurology provider for follow-up if they do not have a team physician to visit.

There are multiple free resources available to providers who are interested in learning more about concussion and educating patients.  The Sport Concussion Assessment Tool – 5th Edition (SCAT5) is an in-depth evaluation tool that is often used by Sports Medicine clinicians when evaluating the extent and severity of a patient’s concussion syndrome.  These resources are listed here:

References

American Medical Society for Sports Medicine position statement on concussion in sport:

https://bjsm.bmj.com/content/53/4/213

SCAT5:

https://bjsm.bmj.com/content/bjsports/early/2017/04/26/bjsports-2017-097506SCAT5.full.pdf

Jacob Stelter, MD

Emergency Medicine, Primary Care Sports Medicine

Division of Emergency Medicine

NorthShore University HealthSystem

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How To Cite This Post:

[Peer-Reviewed, Web Publication] Green, K. Maivelett, J. (2021, Feb 14). What to expect when you're expecting a concussion. [NUEM Blog. Expert Commentary by Stelter, J]. Retrieved from http://www.nuemblog.com/blog/concussion.

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Pericardiocentesis

Written by: David Feiger, MD (NUEM ‘22) Edited by: Abiye Ibiebele, MD (NUEM ‘21) Expert Commentary by: Daniel Schimmel, MD, MS

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Introduction

An emergent pericardiocentesis may be a life-saving procedure and is indicated in patients with pericardial effusion and associated hemodynamic instability. The degree of pericardial effusion severity lies on a continuum and when associated with hemodynamic instability, is known as cardiac tamponade. The volume and rate at which the effusion develops most affects a patient’s hemodynamics. The clinical exam findings – hypotension, distant heart sounds, and jugular venous distention (known as Beck’s Triad) – often do not occur simultaneously if cardiac tamponade is suspected and confirmed early.

Given the urgency of the situation and severity of the patient’s clinical status, blind insertion of a needle into the pericardial space using anatomic landmarks has historically been the method of choice to restore hemodynamic stability. The availability of bedside ultrasound in many emergency departments more recently has led many physicians to pursue an image-guided pericardiocentesis. Various studies have demonstrated decreased mortality and morbidity with an ultrasound-guided approach when compared to a blind approach. However, depending on the clinical context and tools available, a blind approach may be the optimal choice. 

Indications and Contraindications

Hemodynamic instability secondary to pericardial effusion, is the number one reason to perform an emergent pericardiocentesis in the emergency room. Pericardiocentesis for patients with symptomatic pericardial effusion but without hemodynamic instability may be deferred to inpatient management. 

An emergent pericardiocentesis has few contraindications. Aortic dissection or cardiac free wall rupture is sometimes considered an absolute contraindication to pericardiocentesis, but in the absence of immediately available life-saving procedures, pericardiocentesis should be strongly considered. Relative contraindications include use of anticoagulation, platelets < 50K, and uncorrected coagulopathy. Furthermore, trauma patients with hemopericardium should preferentially undergo surgical pericardial drainage or emergency thoracotomy. 

Blind Emergent Pericardiocentesis

Relevant Anatomy to Keep in Mind

Internal thoracic artery (internal mammary artery) – artery running cephalad to caudal on the anterior chest wall parallel to the sternum bilaterally

Neurovascular bundle – a collection of an intercostal vein, artery, and nerve running caudal to each rib

Materials

• Sterile gloves, gown

• Chlorhexidine swab

• At least a 7 cm 18-gauge spinal needle or introducer needle if planning for continuous access to pericardial space

• Syringes (10mL and 60-80mL)

• Three-way stopcock

• Plastic drainage tubing

• Surgical clamp (optional)

1) Position the patient appropriately.

Provide respiratory support with nasal cannula or mechanical ventilation as indicated. Placing patients upright at 30 degrees to enhances comfort and allows gravity-dependent pooling of pericardial fluid.

2) Select an entry site.

Left parasternal and apical approaches are the most commonly pursued and have been shown to be superior to the classic subxiphoid approach in observational studies. When selecting an entry point, recall the location of the internal thoracic artery and subcostal neurovascular bundle. Cleanse a large area of the chest and upper abdomen with the chlorhexidine swab.

3) Insert and advance the spinal needle.

Insert the spinal needle into skin. Once the bevel is in the skin, remove the stylet, attach a three-way stopcock with a large volume syringe attached and maintain negative pressure as you advance the needle. Avoid sliding the needle laterally to prevent lacerating tissues. If a different trajectory is required, retract the needle, keeping the bevel in the skin and drive the needle at the desired angle maintaining negative pressure on the syringe. Momentary resistance may be met as the needle approaches the pericardium, but with continued advancement, a “pop” may be felt followed by aspirate in the syringe and improving patient hemodynamics. See below for more detailed instructions for each approach.

Subxiphoid

Insertion: 1 cm inferior to the left xiphocostal angle, 30 degrees with the patient’s chest

Direction: Towards left mid-clavicle. If unsuccessful, retract the spinal needle and redirect 10 degrees towards the patient’s right

Parasternal

Insertion: Fifth intercostal space at the left parasternal border no more than 1 cm lateral, cephalad to the inferior rib and perpendicular to the patient’s chest

Direction: Posterior

Apical

Insertion: Fifth, sixth, or seventh left intercostal space approximately 6 cm from the parasternal border, cephalad to the inferior rib

Direction: Patient’s right shoulder

4) Draining the pericardial effusion.

Steady the needle with a surgical clamp at the needle shaft closest to the surface of the skin effectively preventing further needle advancement. Attach the plastic tubing to the stopcock allowing emptying of the syringe contents into a collecting vestibule without exchanging syringes. If planning to place a more permanent line (see “Establishing Continuous Access to the Pericardial Space”), consider aspirating just enough fluid to stabilize the patient’s hemodynamics and leave the remaining pericardial fluid to provide space for placing a line.

Tips for Pericardiocentesis with Ultrasound Guidance

Additional materials:

• Bedside ultrasound

• Sterile ultrasound probe cover

• Skin marker

The safety and success of the steps above can be enhanced with bedside ultrasound. Bedside ultrasound can help prior to the procedure by finding the largest effusion nearest the skin and during the procedure by visualizing the needle trajectory in order to avoid important organs and other structures.  There are several methods of ultrasound use in pericardiocentesis.

In static guidance, ultrasound is only used for procedure planning. The subxiphoid, parasternal, and apical views can be explored to find the largest effusion and determine the optimal entry. Often, the needle entry point is marked with a skin marker and another mark is made for the planned trajectory. Distance and angle from the skin to the effusion is also noted.

In dynamic guidance, the needle is passed through the skin parallel to the 2D plane created by the ultrasound probe after finding an effusion pocket. The needle can be visualized as it is advanced towards the pericardial effusion and enters the pericardial space.

No ultrasound? Hook up an EKG!

Additional materials:

• Continuous EKG monitor

• Wire with alligator clips

A continuous EKG can be used to prevent inadvertent traversing of the myocardium with the needle without an ultrasound. Attach one alligator clip to the needle and the other to an anterior lead on a continuous EKG. ST-elevations will be apparent on the EKG if the myocardium is touched. If ST-elevations are noted, simply retract the needle.

Confirmation of Pericardial Access with Ultrasound Guidance

Additional materials:

• Bedside ultrasound

• Two 10 mL syringes (one with 4 mL of saline, one with 0.5 mL of air)

Confirming success in accessing the pericardial space can also be made injecting agitated saline and visualizing bubble artifact on ultrasound. To do so, attach the two saline syringes to the three-way stopcock. Turn off access towards the patient and rapidly push the contents from one syringe to the other until the fluid appears opacified. When all the saline is in one syringe, close off the access to the empty syringe and push the fluid towards the patient, visualizing it on the ultrasound. Confirmation is especially important when blood is aspirated and helps distinguish between pericardial versus ventricular placement.

Establishing Continuous Access to the Pericardial Space

Additional materials:

• Flexible or curved-tip (J) guidewire

• 6-8 Fr drainage catheter (pigtail, sheath, or central venous catheter)

• 7 cm or longer 18-gauge introducer needle (as opposed to spinal needle)

• Dilator

• 11 blade scalpel

• Suture

• Needle driver

Many of the materials above may be found in a central venous kit. Using the Seldinger technique, a line can be placed for continuous access to the pericardial space. Ensure that an introducer needle is used when initially accessing the pericardial space. Keeping the surgical clamp and needle in place, remove the stopcock and syringe, and gently advance the guidewire just beyond the bevel of the needle. Remove the introducer needle, ensuring the guidewire does not move, and use the scalpel to make a short incision at the guidewire’s entry into the skin. Advance the dilator over the guidewire to loosen the tissue. Remove the dilator leaving the guidewire in place and advance the drainage catheter just 1 cm beyond the guidewire into the pericardial space. Retract the guidewire while maintaining the position of the catheter, aspirate fluid to confirm placement, and secure the drain’s position with sutures and placement of a sterile dressing. Further confirmation of proper placement can be made using the agitated bubble study as described in “Confirmation of Pericardial Access with Ultrasound” above.

Conclusion

There are very few contraindications for an emergent pericardiocentesis in a patient with pericardial effusion and hemodynamic instability. While ultrasound-guided pericardiocentesis have lower morbidity and mortality rates, clinical context and emergent patient decompensation may make an image-guided procedure infeasible. Apical and parasternal access with a blind procedure have fewer complications than a subxiphoid approach. A pericardiocentesis may be a life-saving intervention as even a small amount of fluid aspirated may dramatically improve a patient’s hemodynamics.

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Expert Commentary

Thank you Dr. Feiger for this excellent summary of pericardiocentesis.  From center to center there can be variability in the expertise and mechanism through which pericardiocentesis is performed.  Some institutions may have an echo focused pericardiocentesis service, while some institutions may perform the bulk of their pericardiocentesis in an interventional suite with the assistance of fluoroscopic imaging.  However, there are times when pericardiocentesis must be performed as an emergency procedure with landmark guidance.  Luckily, point of care ultrasound has been very commonplace in the emergency department and intensive care units facilitating visualization of fluid pockets that can be identified for safer access and to demonstrate successful drainage at the end of the procedure.  

The relevant anatomy and associated complications from tissue injury during needle advancement for pericardiocentesis changes depending on the planned access route.

Subcostal

• Liver laceration or puncture

• Pneumothorax

• Right atrial or ventricular laceration

Apical

• Pneumothorax

• Left or right ventricular laceration

Parasternal

• Pneumothorax

• Right ventricular laceration

In each location, careful use of ultrasound can avoid potential life-threatening complications.  How the ultrasound is used also varies depending on location.  Generally the ultrasound can be used to identify a path and I will have trainees hold the ultrasound the exact same way as they would hold their needle to mimic the path they will use when advancing into the pericardial space.  

Common errors that I have seen are listed below.

1. Moving the needle side to side while it is in the body to try and find the appropriate space.  I am impressed at the body’s ability to tolerate a straight in and out movement of a needle.  But moving a needle tip back and forth creates lacerations that are difficult to heal and may result in tissue damage and uncontrollable bleeding requiring surgical intervention.

2. Moving the needle to find it under ultrasound, rather than moving the probe to find the needle can be dangerous.  If the needle is in the wrong location, it should be moved.  Otherwise, do not bounce the needle within the body to try and identify it on ultrasound.

3. A common subcostal error is needle path facing towards the spine through the torso.  The subcostal position can be more successful with the patient upright at 30 degrees so that the fluid layers to the bottom portion of the heart, increasing the pocket size for needle entry.  However, this position then requires the physician to aim slightly up, almost moving parallel to the ribs, to avoid needle entry being too low and passing underneath the effusion.

4. Also from the subcostal position, the initial position angle for subcostal pericardiocentesis should be to the left middle cervical bone as Dr. Feiger mentioned.  However, many performing subcostal pericardiocentesis overcompensate initially and head too laterally to capture fluid. 

5. From the apical position, the fluid is likely best obtained with the patient in the left lateral decubitus position.  A drop door that is often present on an sonographer’s bed for performing echocardiograms is nice but not necessary.

As mentioned, the cardiac probe is not generally used to watch needle entry but to identify the most optimal path.  However, if also equipped with a vascular probe, in the parasternal location, the vascular probe can easily watch the needle enter into the pericardial space while avoiding delicate structures like the internal thoracic artery.

Using fluoroscopic guidance, needle location can be identified in relation to the movement of the cardiac border and wire advancement can be used to identify a course consistent with the pericardial space and not limited by other cardiac structures.  A small amount of contrast can be injected into the space and seen to highlight the cardiac borders allowing confirmation of the pericardial space.   

But in the absence of fluoroscopy, and a more specific confirmation, an echo with agitated bubbles injected can verify presence of the needle, or a microcatheter, in the pericardial space.  If after injection, bubbles are seen within the cardiac chambers, the needle should be withdrawn.  If possible to obtain a pressure measurement during the procedure, this is one other guide to inform the operator of the needles location.  If a right ventricular waveform Is present, the needle has entered the ventricular space.  It may be possible to withdraw the needle until the high pressures of the ventricle reduce and if the needle aspirates, another agitated bubble injection can be performed.

An urgent pericardiocentesis with a large effusion can be easily performed at the bedside, particularly with the aid of an ultrasound and knowing the anatomy with immediate improvement in hemodynamics.  Send the fluid for analysis and exchange the needle for a drain to ensure patient stability until the evaluation is complete.

Daniel Schimmel, MD, MS

Interventional Cardiologist

Northwestern Memorial Hospital

Associate Professor

Feinberg School of Medicine

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How To Cite This Post:

[Peer-Reviewed, Web Publication] Feiger, D. Ibiebele, A. (2021, Feb 8). Pericardiocentesis. [NUEM Blog. Expert Commentary by Schimmel, D]. Retrieved from http://www.nuemblog.com/blog/pericardiocentesis.

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References

1. Gueria, Rajesh. “Ultrasound Guided Procedures in Emergency Medicine Practice - Pericardiocentesis.” Sonoguide, 2008, www.acep.org/sonoguide/pericardiocentesis.html.

2. Heffner, Alan C. “Emergency Pericardiocentesis.” Edited by Allan B Wolfson et al., UpToDate, 29 May 2019, www.uptodate.com/contents/emergency-pericardiocentesis?search=pericardiocentesis&source=search_result&selectedTitle=1~65&usage_type=default&display_rank=1.

3. Konnoff-Phillips, Kelly and Janis Provinse, directors. Agitated Saline Bubble Study. Highland Hospital Emergency Department, 2015.

4. Maisch, Bernhard, and Sabine Pankuweit. Interventional Pericardiology: Pericardiocentesis, Pericardioscopy, Pericardial Biopsy, Balloon Pericardiotomy, and Intrapericardial Therapy. Springer, 2011.

5. Nicks, Bret A, et al. Emergency Pericardiocentesis. New England Journal of Medicine, 22 Mar. 2012, www.nejm.org/doi/full/10.1056/NEJMvcm0907841.

Kawasaki Disease

Written by: Richmond Castillo, MD (NUEM ‘23) Edited by: Andra Farcas (NUEM ‘21) Expert Commentary by: Wee-Jhong Chua, MD

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Expert Commentary

A great summary of a rare, but important illness to consider in children with prolonged fevers. Kawasaki disease is a vasculitis to small and medium vessels, often occurring in childhood. While most children recover, there are important cardiac complications that need to be considered. Treatment with IVIG within the first 10 days of illness has been shown to reduce the prevalence of coronary artery aneurysms. In fact, untreated disease has been associated with an incidence of coronary artery aneurysm as high as 25%. [1]

The diagnosis of this disease process is challenging as there are no definitive testing methodologies and even the etiology of the systemic inflammatory process remains unknown. While most guidelines include 5 days of fever, the 2017 American Heart Association Scientific Statement indicates that 4 days of fever with the corresponding clinical features can be diagnostic. Moreover, in rare instances experienced clinicians have been able to make the diagnosis as early as 3 days. [1] In clinical practice, the clinical pathways at leading children’s hospitals use 4 days as a threshold for evaluation with the presence of 4 or 5 principal clinical features are present. [2,3] However, the standard practice continues to be 5 days for the classic diagnosis.

With high clinical suspicion for Kawasaki Disease, transfer to a pediatric hospital should be considered with consultations with Infectious Disease, Cardiology, and Rheumatology. It is important to have a high clinical suspicion for Kawasaki disease in children with prolonged fevers.

References

1. McCrindle BW, Rowley AH, Newburger JW, et al. Diagnosis, treatment, and long-term management of Kawasaki disease: A scientific statement for health professionals from the American Heart Association. Circulation. 2017;135(17):e927-e999. doi:10.1161/CIR.0000000000000484

2. D. Whitney, MD; K. Dorland, BSN; J. Beus, MD; J. Brothers, MD; L. Buckley, MD; S. Burnham MD; D. Campeggio, MSN; K. DiPasquale, MD; H. Ghanem MD; J. Hart MD; J. Lavelle, MD; C. Law PharmD; S. Natarajan, MD; J. Ronan, MD; V. Scheid, MD; S. Swami, MD; H. Ba C. Kawasaki Disease or Incomplete Kawasaki Disease Clinical Pathway — Emergency Department and Inpatient | Children’s Hospital of Philadelphia. Accessed October 20, 2020. https://www.chop.edu/clinical-pathway/kawasaki-disease-incomplete-kawasaki-disease-clinical-pathway

3. Seattle Children’s Hospital, M Portman, M Basiaga, E Beardsley, R Engberg, K Hayward, K Kazmier, M Leu, R Migita, J Rasiah, R Sadeghian, S Sundermann, S Vora, S Zaman, 2018 February. Kawasaki Disease Pathway. Available from: http://www.seattlechildrens.org/pdf/Kawasaki-Disease-Pathway.pdf

Wee-Jhong Chua, MD

Attending Physician, Pediatric Emergency Medicine

Ann & Robert H. Lurie Children's Hospital of Chicago

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How To Cite This Post:

[Peer-Reviewed, Web Publication] Castillo, R. Farcas, A. (2021, Feb 1). Kawasaki Disease. [NUEM Blog. Expert Commentary by Chua, W]. Retrieved from http://www.nuemblog.com/blog/kawasaki-disease.

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Apple Heart Study

Written by: Em Wessling, MD (NUEM ‘22) Edited by: Dana Loke, MD (NUEM ‘19) Expert Commentary by: Rod Passman, MD

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Chief Complaint: My watch thinks I have Atrial Fibrillation!

 As technology advances, medicine must continue to advance in pace. Wearable technology has been evolving for decades. The information gathered from a wide range of these devices may someday help to provide healthcare workers with valuable information about a patient’s condition. However, for now, there is limited research on their utility within the healthcare field.

 Thus far, both Apple Watch and Fitbit have been shown to correctly identify tachycardia during atrial tachyarrhythmias, but their accuracy to the heart rate varied with the type of arrhythmia (1,2). Apple Watch has been shown to be more accurate than Fitbit (1,2). The WATCH AF trial demonstrated it was possible with reasonable sensitivity (93.7%) and specificity (98.2) to use smart watches to diagnose Atrial Fibrillation (3). 

How Apple Watch is tracking atrial fibrillation:

-        Photoplethysmography: the use of light to determine volume within a structure at a given time

-        Pulse is estimated by time between peak volume seen by photoplethysmography.

-        When the pulse is highly variable between consecutive beats, irregular heart beat is suspected.

Apple Heart Study: The plan and the preliminary data (4, 5)

Study Design: Prospective, single arm pragmatic study

-        Enrolled 419,093 participant  

-        Inclusion Criteria: appropriate Apple technology, Age≥22 years, US resident, proficient in English, valid phone number and email.

-        Exclusion criteria: self-reported atrial fibrillation , atrial flutter, or anticoagulation

-        Methods:  “Irregular Pulse Notification” (indication of possible atrial fibrillation) sent to participants  if 5/6 irregular pulses within  48 hour period, at which point participant was instructed to wear EKG patch for up to 7 days.

-        Primary Outcome: Proportion of patients alerted with “Irregular Pulse Notification” who were found to have atrial fibrillation or atrial flutter on EKG patch, in the 65+ population as well as in all-comers.

-        Secondary Outcomes: Positive predictive value (PPV) of irregular heart rhythm notification; percentage of those with irregular notification who contacted a health care professional within 3 months.

Preliminary Data presented at ACC:

-        Participants who received “Irregular Pulse Notification”:  2,161 (0.52% all comers)

-        Participants age >65 who received “Irregular Pulse Notification”: >3%

-        EKG Patches sent to 658 participants; 450 returned.

• 34% of those returned showed atrial fibrillation

• PPV for Tachogram: 71%

• PPV for “Irregular Pulse Notification”: 84%

-        Notification to doctor - approx. 50%

Limitations:

• Small sample size for EKG patches, despite high enrollment

• Self-reported data

• Self-selecting group, i.e.may not be able to extrapolate prevalence data to those who do not wear smart watches

Potential Impact on Emergency Departments:

As more and more studies validate the accuracy of wearable technology to measure and recognize health conditions, the implications must be analyzed as well.

Prior to 2017, researchers began to predict that there would be an expansive increase in the rates of atrial fibrillation due to “worldwide aging” (6). While this review acknowledged there were “potential applications” for smart phone technology in the diagnosis, their predictions of the expanse of the epidemic of atrial fibrillation preceded definitive research showing increased diagnosis rates with wearable technology, which will likely only further expedite this growing patient population.  The mSToPS Trial showed that immediate in-home monitoring with an EKG patch had 3% greater rates of atrial fibrillation diagnosis compared to delayed EKG monitoring at 4 months. This led to increased use of anticoagulants and increased health care utilization (7). If this increase was seen with EKG patches, consider the influx of patients to primary care and cardiology clinics in addition to emergency departments that can be projected based on the rise of smart watch detection of atrial fibrillation. Researchers in Australia had begun studying this prior to the commencement of the Apple Heart Study (8). When cardiac patients were asked if they trusted smart watches to predict arrhythmia and measure their heart rate only 53% agreed; however, that did not stop 91% from reporting they would seek care if their watch alerted them about an abnormality (8). While the preliminary data from the Apple Heart study shows that a much smaller percentage of those who were not previously cardiac patients sought medical care when alerted by their Apple Watch, further study is needed to see the extent to which advances in smart watch health technology will lead to an influx in patients to the Emergency Department due to concerns of arrhythmia found by a smartwatch (5).

 While the accuracy of these methods of arrhythmia detection are still being studied, the potential for ED presentation with this chief complaint will continue to rise. In the fourth quarter of 2017 financial year, Apple alone sold greater than 8 million smart watches worldwide, making it the largest watch vender in the world (9).  With these increased sales, comes the potential for increased recognition of arrythmia by smartwatch. Healthcare organizations throughout the country must strive to develop effective and efficient clinical pathways in order to evaluate, potentially diagnose, and treat this patient population. Upon presentation to the Emergency Department, each patient should receive an EKG, telemetry monitoring while in the Emergency Department and screaming lab work: often including CBC, BMP + Mg, and troponin.  From there, the pathway may vary. Many would agree, if the patient is and has always been asymptomatic, work up is unremarkable, with normal sinus rhythm on their EKG, discharge home with an EKG patch and follow up with cardiology is reasonable. Conversely, an EKG showing atrial fibrillation would constitute a new diagnosis and further work up would proceed as with any other new diagnosis of Atrial Fibrillation. However, for those who fall in-between, the disposition is not as clear. What would you do?

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Expert Commentary

More than 800 years ago, Maimonides described an irregular pulse that likely represented atrial fibrillation (AF). The development of the electrocardiogram by Einthoven 700 years later allowed surface recordings of human AF for the first time.1 With the recognition that AF is often asymptomatic and paroxysmal, the development of inexpensive, non-invasive, passive monitors for irregular rhythm identification has long been recognized as a potentially important tool for arrhythmia detection and management.

At its core (pun intended), the purpose of the Apple Heart Study was to assess the feasibility of AF screening in large populations by monitoring participants with a wrist-worn photoplethysmography (PPG) monitor.2 The PPG algorithm in the Apple Watch samples the pulse several times daily during periods of physical inactivity and increases the sampling rate if an irregular tachogram is detected. If 5 out of 6 tachograms are consistent with AF (requiring > 60 minutes of AF), the wearer receives an irregular rhythm notification. Since the version of the Apple Watch used in the study did not have the 30-second ECG feature (available in Series 4 watches and later), the Apple Heart Study protocol asked those who received the irregular rhythm notification to wear an ECG patch at a later date. 

Several important facts can be gleaned from the Apple Heart Study.  First, the study virtually enrolled 419,297 individuals in less than a year, a testament to the interest in the subject matter, the ease of remote enrollment when appropriate, and the enormous potential of digital health studies. Second, the fear that the healthcare system would be inundated with false positive AF notifications appears unfounded as 99.8% of participants under age 40 did not receive an irregular rhythm notification.  Third, the positive predictive value for the irregular rhythm notification was surprisingly high (84%) despite that fact that the patch was applied a mean of 13 days following the notification and was worn for less than 7 days on average. This last point is worth emphasizing since with paroxysmal AF, a negative monitor placed two weeks after an irregular rhythm notification may simply mean that AF was not present during both time periods.

The study also has some important caveats.  The Apple Heart Study did not report the sensitivity and specificity of the PPG algorithm for AF detection, a critical piece of missing data needed for clinical care and future research. Furthermore, only a minority of patients who received an irregular rhythm notification actually wore and returned the ECG monitor, showing that virtual enrollment doesn’t always translate into virtual protocol compliance. From a research perspective, wearable AF monitors have allowed for large-scale screening studies such as the Huawei  Heart and Heartline Studies aimed at understanding the true prevalence of AF and the risks and benefits of early detection and treatment.3,4 From a clinical perspective, a patient who says “my watch says I have AF” still requires ECG confirmation, but that too has been made easier with the new generation of wearables.

References

1. Prystowsky EN. The history of atrial fibrillation: the last 100 years. J Cardiovasc Electrophysiol. 2008;19(6):575-582. doi:10.1111/j.1540-8167.2008.01184.

2. Perez MV, Mahaffey KW, Hedlin H, et al. Large-Scale Assessment of a Smartwatch to Identify Atrial Fibrillation. N Engl J Med. 2019;381(20):1909-1917. doi:10.1056/NEJMoa1901183

3. Guo Y, Wang H, Zhang H, et al. Mobile Photoplethysmographic Technology to Detect Atrial Fibrillation. J Am Coll Cardiol. 2019;74(19):2365-2375. doi:10.1016/j.jacc.2019.08.019

4. www.heartline.com

Rod Passman, MD

Professor, Feinberg School of Medicine

Cardiac Electrophysiology

Northwestern Memorial Hospital

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How To Cite This Post:

[Peer-Reviewed, Web Publication] Wessling, E. Loke, D. (2021, Jan 25). Apple Heart Study. [NUEM Blog. Expert Commentary by Passman, R]. Retrieved from http://www.nuemblog.com/apple-heart.

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References

1. Koshy, Anoop N., et al. "Smart watches for heart rate assessment in atrial arrhythmias." International journal of cardiology 266 (2018): 124-127.

2. Koshy, A., et al. "Heart Rate Assessment by Smart Watch: Utility or Futility?." Heart, Lung and Circulation 26 (2017): S280-S281.

3. Dörr, Marcus, et al. "The WATCH AF trial: SmartWATCHes for detection of atrial fibrillation." JACC: Clinical Electrophysiology5.2 (2019): 199-208.

4. Turakhia, Mintu P., et al. "Rationale and design of a large-scale, app-based study to identify cardiac arrhythmias using a smartwatch: The Apple Heart Study." American heart journal207 (2019): 66-75.

5. ACC News Story. “Apple Heart Study Identifies AFib in Small Group of Apple Watch Wearers.” American College of Cardiology: Latest in Cardiology, American College of Cardiology, 16 Mar. 2019, www.acc.org/latest-in-cardiology/articles/2019/03/08/15/32/sat-9am-apple-heart-study-acc-2019.

6. Morillo CA, Banerjee A, Perel P, Wood D, Jouven X. Atrial fibrillation: the current epidemic. J Geriatr Cardiol. 2017;14(3):195–203. doi:10.11909/j.issn.1671-5411.2017.03.011

7. Steinhubl SR, Waalen J, Edwards AM, et al. Effect of a Home-Based Wearable Continuous ECG Monitoring Patch on Detection of Undiagnosed Atrial Fibrillation: The mSToPS Randomized Clinical Trial. JAMA.2018;320(2):146–155.

8. Koshy, A., et al. "Cardiac Patients Likely to Seek Medical Assistance Based on Abnormal Heart Rate Readings on Smart Watches or Smartphone ECG Monitors." Heart, Lung and Circulation 26 (2017): S280.

9. Canalys Press Team. “18 Million Apple Watches Ship in 2017, up 54% on 2016.” Canalys Newsroom, Canalys, 6 Feb. 2018, www.canalys.com/newsroom/18-million-apple-watches-ship-2017-54-2016.

Intubating the Pregnant Patient in the ED

Written by: Priyanka Sista, MD (NUEM ‘20) Edited by: Steve Chukwulebe, MD (NUEM ‘19) Expert Commentary by: Samir Patel, MD

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Expert Commentary

Tip for #1 - While 3-5 minutes of 100% oxygen is ideal to achieve denitrogenation, in an emergency 8 vital capacity breaths (maximal inhalation and exhalation) with a high FiO2 source is sufficient in a cooperative patient.

Tip for #2 - Airway edema is even worse in preeclamptic patients, and Mallampati scores acutely worsen DURING labor. Don’t bother with direct laryngoscopy and go straight to the video laryngoscope if it’s available.

Tip for #3 - In this scenario, the ideal LMA or supraglottic airway is one that includes a port for passage of an OG tube. Your pregnant patient in the ER with increased aspiration risk is not likely to be NPO for 8 hours like they are for anesthesiologists before surgery.

Tip for #4 - The rapid sequence dose of rocuronium is 1.2 mg/kg. You can immediately reverse rocuronium with sugammadex 16 mg/kg if necessary. For cost purposes, succinylcholine is still the best choice unless medically contraindicated.

Tip for #5 - According to ACOG, if cardiac arrest occurs in a woman greater than 23 weeks gestation, and there is no return of spontaneous circulation after 4 minutes of correctly performed CPR, a perimortem c-section should be performed with the goal of delivering the fetus by the fifth minute.

Samir K. Patel, MD

Assistant Professor

Northwestern University Feinberg School of Medicine

Department of Anesthesiology

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How To Cite This Post:

[Peer-Reviewed, Web Publication] Sista, P. Chukwulebe, S. (2021, Jan 18). Intubating the pregnant patient in the ED. [NUEM Blog. Expert Commentary by Patel, S]. Retrieved from http://www.nuemblog.com/blog/intubating-the-pregnant-patient.

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Imaging in PTAs

Written by: Cameron Jones, MD (NUEM ‘23) Edited by: Vidya Eswaran, MD (NUEM ‘20) Expert Commentary by: Josh Zimmerman, MD

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The Use of Imaging for Diagnosis and Management of Peritonsillar Abscesses

Among the many causes of sore throat that the EM physician may encounter, peritonsillar abscesses (PTAs) can be one of the more satisfying to diagnose and treat. A straightforward clinical diagnosis followed by a simple procedure resulting in a patient who feels much better than when they arrived...right? But what about that patient with the large, short neck and some drooling? Or the one with severe trismus giving you only the barest of glimpses at the back of their throat? Or, most feared of all, the crying child who develops lockjaw at the first glimpse of a tongue depressor? Maybe we should just get the neck CT to be on the safe side? And didn’t I hear about using ultrasound for this in some lecture? 

What is a peritonsillar abscess (PTA)?

A PTA is a discrete collection of pus between the palatine tonsil capsule and the pharyngeal muscles. It should be distinguished from peritonsillar cellulitis, which is an inflammatory reaction of the same area without a definitive collection. PTAs are often preceded by tonsillitis or pharyngitis with subsequent progression of the infection. However, they may also occur due to salivary gland obstruction without preceding tonsillitis or pharyngitis. Peritonsillar abscess is often considered a clinical diagnosis based on classic symptoms and exam findings:

• Throat pain (sometimes worse on the side of the abscess, but not always)

• “Hot potato” or muffled voice

• Unilateral swollen and erythematous tonsil +/- appreciable fluctuance

• Uvula deviation

What are signs or symptoms suggestive of a more dangerous diagnosis?

Though sometimes mistakenly considered features of more concerning deep space neck infections, all of the following can also be seen with PTA: 

• Neck swelling

• Trismus

• Pooling of saliva (though this should be minor, with minimal drooling)

Other findings or symptoms of more serious deep space infections, such as retropharyngeal abscess:

• Toxic appearance

• Respiratory distress

• Anxious appearance or leaning forward into “sniffing position”

• Significant drooling

• Neck pain or limited ROM out of proportion to presumed diagnosis

When should imaging be considered in the patient with suspected PTAs?

Routine imaging is not indicated for stable patients with a presumptive diagnosis based on exam. Sensitivity and specificity figures in the EM and ENT literature based on clinical exam alone are actually not very high (sensitivity <80% and specificity approximately 50%). However, these oft-cited figures are based on a comparatively small cohort of patients with presumed PTA, and in the large majority of missed diagnoses among this data, the true diagnosis is tonsillitis or peritonsillar cellulitis. CT scans, particularly contrast studies and those involving radiation of the head and neck, are not without risk, and should not be considered a screening study in well-appearing patients.  Therefore, the use of imaging by ED physicians in evaluation of PTAs should really be reserved for 3 purposes:

1. Ruling out serious deep space neck infections, such as retropharyngeal abscesses, in a patient with signs of peritonsillar swelling but some other concerning sign or symptom, as discussed above.

   - CT of the neck with contrast is best used for this purpose

2. Differentiating PTA from peritonsillar cellulitis or tonsillitis by identifying a discrete fluid collection

3. Guiding drainage in order to improve first-attempt success

   - Intraoral or submandibular/transcervical ultrasounds are most appropriate for these purposes

 There are few prospective studies examining the use of CT in uncomplicated PTAs, and those patients with red flags or signs of airway compromise are typically excluded. CT of the neck with IV contrast is nearly 100% sensitive and 75% specific for PTA and similarly accurate for the diagnosis of more dangerous conditions such as retropharyngeal abscesses. Increasingly, ultrasound has also become a useful option for better characterizing the location of abscesses in PTAs. 

Ultrasound offers the added utility of bedside confirmation of a drainable fluid collection and, depending on provider comfort and patient tolerance, may provide real-time guidance for needle drainage. As with other applications of ultrasound, the provider must be comfortable with the technique and relevant anatomy. Prospective data indicates EM providers can become comfortable with tonsillar ultrasound technique in as few as 3-4 patients.  In its use in the ED setting, ultrasound has demonstrated nearly 100% sensitivity in differentiating abscess from non-drainable inflammation or cellulitis. Thus, using ultrasound to confirm abscess in those suspected to have PTA may allow patients without drainable fluid collections to avoid unnecessary aspiration attempts.

Peritonsillar abscess seen on submandibular ultrasound. Adapted from Huang et al. 

Arrows indicating edges of the abscess

T : Tonsil

*  :  Submandibular gland

Peritonsillar abscess on CT. Adapted from Kew et al. 

Arrowheads indicating edges of the abscess.

Is imaging useful for guiding drainage of PTAs?

• Ultrasound has also been studied for its utility in guiding drainage and increasing success rate of aspiration attempts. Some studies have reported low patient tolerance or mechanical challenges when using real-time intraoral ultrasound to guide drainage. However, ultrasound has also been shown to improve success-rate of aspiration attempts even when it is used for preceding visualization of the abscess and not for guided drainage.

• More recently, extraoral ultrasound approaches, such as transcervical/ submandibular, have also been studied as an alternative to intraoral techniques, which can be challenging due to mechanical challenges, severe trismus, or patient discomfort. Very limited data suggests submandibular ultrasound may have lower sensitivity compared to intraoral ultrasound when evaluating PTAs, so caution is also warranted when utilizing this technique. 

Intraoral ultrasound approach

(adapted from Secko, Sivitz, et al.)

Submandibular ultrasound approach

(adapted from Secko, Sivitz et al.)

What about imaging in kids?

CT scans are often ordered in pediatric patients, who may have challenging exams due to patient intolerance, and these imaging studies are particularly common in community settings where ENT expertise is not readily available. Clinical accuracy for diagnosing PTA in children appears even lower than in adults, though, as with adults, in most children incorrectly diagnosed with PTAs, the true diagnosis is tonsillitis without a drainable abscess. Many providers would also prefer to avoid the added radiation exposure of CT scans amongst this population. Thus, extraoral ultrasound approaches may be particularly helpful in pediatric patients, many of whom are unlikely to cooperate with intraoral ultrasound. Transcervical ultrasound has also been shown to reduce length of stay, CT radiation exposure, and procedures performed amongst pediatric patients with suspected PTAs, with no change in readmission rates or treatment failures. Although the extraoral ultrasound approach appears to be more technically feasible in children, use of ultrasound may also be more logistically challenging and staffing-dependent. Scans in these studies were performed and read by radiology technicians and radiologists.  

So what is a reasonable approach to incorporating imaging in suspected PTAs?

The growing body of evidence described above has led to several expert recommendations that ultrasound be the first-line imaging for suspected PTAs. While there is variability in different departments regarding the ED provider’s comfort with bedside tonsillar ultrasound or, alternately, the availability of technicians and radiologists for interpreting formal ultrasounds. However, the use of ultrasound  in non-toxic patients with suspected PTA has been shown to be highly effective in differentiating PTAs from peritonsillar cellulitis or tonsillitis and may save patients the discomfort and time of an unnecessary procedure. CT imaging still has its place in those patients with less certain diagnoses or concerning symptoms, but should be reserved for specific scenarios rather than being ordered routinely. The following is an evidence-based algorithm for incorporating ultrasound and CT imaging into the emergency department evaluation of these patients

* : toxic appearance, substantial drooling, respiratory distress, severe neck pain or swelling, inability to fully range neck

+ : Most patients can be safely discharged with oral antibiotics, return precautions, and ENT follow-up. Exceptions include those patients  who are unable to tolerate oral medications, those with signs or symptoms of severe sepsis, patients with severe dehydration, or patient with severe comorbidities or immunocompromised state

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Expert Commentary

Thank you for an excellent review of a common ED diagnosis.  Sore throats are ubiquitous presenting complaints in any major ED.  The final diagnosis is often uncomplicated pharyngitis, however, recognizing the early and often subtle signs of more serious conditions before a true life threat develops is a critical role for the emergency physician.  While peritonsillar abscesses (PTA) in and of themselves are not typically life threatening, many of the signs and symptoms can overlap with those of more critical diagnoses such as retropharyngeal abscesses and epiglottitis.  

So, that said, when should you consider imaging a patient with a suspected PTA or acute sore throat in general?

The discussion above does a thorough review evidenced based imaging practices and offers a reasonable flowsheet to guide this decision.  In clinical practice imaging should help answer one of two questions: 

• Is a discrete fluid collection present that is amenable to drainage? 

• Are there findings of retropharyngeal or other deep space infection rather than a simple PTA?

I have made it my practice to consider imaging before any attempt at I&D or further care in the following circumstances: 

• Any patient toxic in appearance or with unstable vital signs

• Any patient demonstrating signs of airway compromise 

• Meningismus on exam

• Patients in which at PTA cannot be clearly visualized or lacking the typical secondary findings on exam 

With that list in mind, let us delve into the topic a bit more in detail.  Peritonsillar abscesses represent accumulation of purulent fluid which are unlikely to resolve spontaneously.  Some studies have shown that drainage alone results in >90% cure rate even without antimicrobial therapy. Classically, a PTA will present with trismus, severe pharyngitis, and on pharyngeal exam a displaced tonsil, typically inferiorly and medially, as well as uvular deviation contralateral to the abscess.  PTA can sometimes be confused with peritonsillar cellulitis on examination solely and is often one of the reasons clinicians opt for imaging. Peritonsillar cellulitis does not require drainage as there is no discrete fluid collection.  When there is a more subtle exam, this is one scenario in which imaging may be helpful.   

A practical approach that many ED physicians utilize is to consider a trial of drainage when the diagnosis is readily evident on exam.  As mentioned above, when the classic findings of a displaced tonsil and uvula are present one can have a high probability of successful drainage.  

Adjunct therapy – abx and steroids 

The scope of this segment is meant to focus on imaging and diagnostics but it is worth a brief moment to discuss antimicrobials and adjunct therapy.  While procedural drainage alone results in significant cure rates, it remains common practice to treat PTA’s with antimicrobial therapy as well.  A common misconception is that PTAs are a result of Streptococcal infections.  While Group A Strep is isolated from cultures, these typically tend to be polymicrobic infections with Fusobacterium additionally being a frequent culprit organism.  As such, antibiotic therapy tends to be more broad spectrum with coverage of anaerobic organisms included.  First line therapy remains a penicillin based antibiotic regimen.  Intravenously this can be ampicillin-sulbactam (Unasyn), Piperacillin-Tazobactam (Zosyn) or Ceftriaxone Plus Metronidazole.  In the penicillin allergic patient Clindamycin is a reasonable alternative.  When transitioning to oral therapies, Amoxicillin-Clavulanate (Augmentin) is typically first line therapy with Clindamycin providing a reasonable alternative in penicillin allergic patients.  Therapy typically is for a full 10 days.  

A brief note should be made regarding steroid therapy as well.  Steroids have been shown to provide significant symptomatic relief including decreasing length of symptoms and overall severity.  I typically will give patients a single dose or oral or IV Dexamethasone 10 mg as part of their treatment. 

Joshua Zimmerman, MD

Emergency Medicine Physician

Northwestern Lake Forest Hospital

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How To Cite This Post:

[Peer-Reviewed, Web Publication] Jones, C. Eswaran, V. (2021, Jan 11). Imaging in PTAs. [NUEM Blog. Expert Commentary by Zimmerman, J]. Retrieved from http://www.nuemblog.com/blog/imaging-in-PTAs.

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References

1. Carratola, M. C., Frisenda, G., Gastanaduy, M., & Lindhe Guarisco, J. (2019). Association of Computed Tomography With Treatment and Timing of Care in Adult Patients With Peritonsillar Abscess. Ochsner Journal, 19, 309–313. https://doi.org/10.31486/toj.18.0168

2. Costantino, T. G., Satz, W. A., Dehnkamp, W., & Goett, H. (2012). Randomized Trial Comparing Intraoral Ultrasound to Landmark-based Needle Aspiration in Patients with Suspected Peritonsillar Abscess. Academic Emergency Medicine, 19(6), 626–631. https://doi.org/10.1111/j.1553-2712.2012.01380.x

3. Cunha, B., Filho, A., Sakae, F. A., Sennes, L. U., Imamura, R., & De Menezes, M. R. (n.d.). Intraoral and transcutaneous cervical ultrasound in the differential diagnosis of peritonsillar cellulitis and abscesses Summary. Brazilian Journal of Otorhinolaryngology, 72(3), 377-81. http://www.rborl.org.br/

4. Fordham, M. T., Rock, A. N., Bandarkar, A., Preciado, D., Levy, M., Cohen, J., … Reilly, B. K. (2015). Transcervical ultrasonography in the diagnosis of pediatric peritonsillar abscess. The Laryngoscope, 125(12), 2799–2804. https://doi-org/10.1002/lary.25354

5. Froehlich, M. H., Huang, Z., & Reilly, B. K. (2017, April 1). Utilization of ultrasound for diagnostic evaluation and management of peritonsillar abscesses. Current Opinion in Otolaryngology and Head and Neck Surgery. Lippincott Williams and Wilkins. https://doi.org/10.1097/MOO.0000000000000338

6. Herzon, F. S., & Martin, A. D. (2006). Medical and Surgical Treatment of Peritonsillar, Retropharyngeal, and Parapharyngeal Abscesses. Current Infectious Disease Reports, 8:196–202. https://doi.org/10.1007/s11908-006-0059-8

7. Huang, Z., Vintzileos, W., Gordish-Dressman, H., Bandarkar, A., & Reilly, B. K. (2017). Pediatric peritonsillar abscess: Outcomes and cost savings from using transcervical ultrasound. The Laryngoscope, 127(8), 1924–1929. https://doi.org/10.1002/lary.26470

8. J Scott, P. M., Loftus, W. K., Kew, J., Ahum, A., Yue, V., & Van Hasselt, C. A. (2020). Diagnosis of peritonsillar infections: a prospective study of ultrasound, computerized tomography and clinical diagnosis. The Journal of Laryngology and Otology, 113, 229–232. https://doi.org/10.1017/S0022215100143634

9. Kew, J., Ahuja, A., Loftus, W. K., Scott, P. M. J., & Metreweli, C. (1998). Peritonsillar Abscess Appearance on Intra-oral Ultrasonography. Clinical Radiology (Vol. 53).

10. Lyon, M., & Blaivas, M. (2005). Intraoral Ultrasound in the Diagnosis and Treatment of Suspected Peritonsillar Abscess in the Emergency Department. Academic Emergency Medicine, 12(1), 85–88. https://doi.org/10.1111/j.1553-2712.2005.tb01485.x

11. Nogan, S., Jandali, D., Cipolla, M., & DeSilva, B. (2015). The use of ultrasound imaging in evaluation of peritonsillar infections. The Laryngoscope, 125(11), 2604–2607. https://doi.org/10.1002/lary.25313

12. Patel, K. S., Ahmad, S., O’leary, G., & Michel, M. (1992). The role of computed tomography in the management of peritonsillar abscess. Otolaryngology--Head and Neck Surgery, 107(6), 727-732.  https://doi.org/10.1177/019459988910700603.1 

13. Powell, J., & Wilson, J. A. (2012). An evidence-based review of peritonsillar abscess. Clinical Otolaryngology, 37(2), 136–145. http://doi.wiley.com/10.1111/j.1749-4486.2012.02452.x

14. Salihoglu, M., Eroglu, M., Osman Yildirim, A., Cakmak, A., Hardal, U., & Kara, K. (2013). Transoral ultrasonography in the diagnosis and treatment of peritonsillar abscess. https://doi.org/10.1016/j.clinimag.2012.09.023

15. Valdez, T. and Vallejo, J., 2016. Infectious Diseases In Pediatric Otolaryngology. Springer International Publishing.

Mobile Integrated Health

Written by: Ezekiel Richardson, MD (NUEM ‘23) Edited by: Alex Herndon, MD (NUEM ‘21) Expert Commentary by: Hashim Zaidi, MD

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Introduction

Community Paramedicine, also known as Mobile Integrated Health (MIH), is a developing field in which paramedics and emergency medical technicians assist under-resourced areas in the provision of public health, primary healthcare, and preventive services. The express goal of these services is to “improve access to care and avoid duplicating existing services.” [1] While community paramedicine was pioneered in rural settings in which distance significantly limited the patients’ access to primary care and public health, it has continued to expand from rural areas that are underserved into underserved suburban and urban centers.

Across the nation, community paramedicine has taken on may roles, from providing primary prevention and onsite triage in Minneapolis, targeting emergency medicine “hot spots” for prevention of 911 calls in Ontario, to leveraging telemedicine to allow a physician to triage 911 dispatches, paramedic assessment, and diverting patients to primary care in Houston. [2,3,4]

In the United States we have seen a slow and steady migration of low-income individuals out of cities. Nearly 60% of all low-income individuals live outside the city limits of the nearest metropolitan area. [5] Suburban poverty has increased by half in most major metropolitan cities including Chicago. [6] Notably, a significant amount of literature suggests that wealthy and middle class suburbs (whose health infrastructure was built to support individuals with income and agency) are now facing a massive migration of low-income citizens. [7, 8] Accordingly, new healthcare solutions like MIH will be of paramount importance as trends in American migration continue as they have over the last 50 years.

In places like Houston, Minneapolis, and Ohio City where a single healthcare system captures a large share of the patient population and sees a significant amount of the costs from ambulance runs, those healthcare systems have funded community paramedics to assess high-volume patients and if medically appropriate, divert them triggering an ambulance run to the Emergency Department. [2, 4, 9]

In Minneapolis, this was done by staffing a community paramedic at a homeless shelter and community shelter that saw frequent ambulance calls and transports after clients left for the night and may have forgotten medications, developed asthma exacerbations, or minor injuries. [2]

In Houston, telemedicine equipment and a part time emergency medicine physician allowed remote evaluation in a patient’s home with a walk around tour a referral for certain home care services, medication refills, and primary care appointments.4 Houston’s program showed significant improvement in efficiency. Of the 5,570 patients participated, 18% received ambulance transport as opposed to 74% and EMS crews returned to service 44 minutes faster than prior. [10]

In Ohio City, frequent fliers who have called and been transported to the emergency department more than 10 times in 24 months will be given the option to have community paramedics perform a home assessment and ensure that they have the equipment and primary care to avoid emergency department visits. [7]

In Ontario, a community paramedic was stationed in a random apartment building selected for high volume and proportion of elderly individuals and a high frequency of EMS calls. There the paramedic was able to assess the health of residents, answer questions, and provide basic health education, as well as had the ability to activate emergency transport and provide basic primary care. The intervention showed evidence of an increase in the amount of Quality Adjusted Life Years, a decrease in blood pressure among study participants, as well as a significant decrease in EMS calls, thus making a difference in both patient health outcomes and proper utilization of emergency health systems. [11]

Conclusions

While community paramedicine is a promising new intervention as populations age and migrate out from urban centers, there is still sparse data on its success. Even the data that does exist raises serious questions about reproducibility from both a clinical results standpoint and an intervention oversight. However, community paramedicine’s strength may be in its flexibility and the freedom of enterprising EMS directors, public health, and city safety officials to tailor a program to a city’s needs and available budget.

Limitations

In Minneapolis, the community paramedicine program was not renewed because of difficulty quantifying cost savings and proving financial feasibility. Ohio City’s program is too early to yield results. Houston’s program and Ontario’s program have produced literature supports the notion that paramedicine can reduce EMS calls and costs spent on transportation and emergency evaluation.

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Expert Commentary

Thank you to the authors for touching on a critical subject that has only become even more important during a global pandemic. Mobile Integrated Healthcare (MIH) – also known as Community Paramedicine – shows significant promise in providing resources to those disenfranchised from healthcare.

The 1996 EMS Agenda for the Future calls for EMS to one day serve as “community-based health management that is fully integrated with the overall health care system…integrated with other health care providers and public health and public safety agencies. It will improve community health and result in more appropriate use of acute health care resources. EMS will remain the public’s emergency medical safety net.” Nearly a quarter of a century later we are getting the necessary footholds to move this vision from fantasy to reality while still recognizing the need for EMS as the public’s emergency medical safety net. The Center for Medicare & Medicaid Services (CMS) has recognized the value of leveraging existing EMS resources to further the mission of community-based health management.

The ET3 model unveiled earlier this year by CMS describes a 5-year payment model that will pay participating EMS services for 1) transport an individual to a hospital emergency department (ED) or other destination covered under the regulations, 2) transport to an alternative destination partner (such as a primary care doctor’s office or an urgent care clinic), or 3) provide treatment in place with a qualified health care partner, either on the scene or connected using telehealth. This shows the promise of incentives to reduce unnecessary transports but also to reimburse for services rendered by EMS. This applies in novel interventions such as mobile integrated healthcare but also in more common scenarios. Imagine what a model such as this could do with those who are quarantined at home or in shelters with COVID but require regular telehealth check ups for chronic disease management. Or even more simply, community members who need someone to help ensure they have food and running water.

MIH is a promising field that builds on the foundation of EMS being a community-based healthcare entity as opposed to a patient transportation service. MIH, particularly for the most vulnerable populations frequently served by EMS and the ED, stand to benefit the most with models such as this. EMS has come a long way from “you call, we haul” and initiatives such as MIH should be supported and financially fostered in communities by local and state agencies.

Hashim Zaidi, MD

McGovern Medical School

Assistant Professor

Harris Health System

Medical Director

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How To Cite This Post:

[Peer-Reviewed, Web Publication] Richardson, Ezekiel. (2021, Jan 4). Mobile Integrated Health [NUEM Blog. Expert Commentary by Zaidi, H]. Retrieved from http://www.nuemblog.com/blog/mobile-integrated-health

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Other Posts You May Enjoy

References

1. https://www.cdc.gov/dhdsp/pubs/docs/SIB_Feb2019-508.pdf. (2020) Retrieved January 7, 2020

2. “Community Paramedicine: A Simple Approach To Increasing Access To Care, With Tangible Results, " Health Affairs Blog, October 31, 2017. DOI: 10.1377/hblog20171027.424417

3. Dainty, K. N., Seaton, M. B., Drennan, I. R., & Morrison, L. J. (2018). Home visit‐based community paramedicine and its potential role in improving patient‐centered primary care: a grounded theory study and framework. Health services research, 53(5), 3455-3470.

4. Langabeer, J. R., II, M. G., Alqusairi, D., Champagne-Langabeer, T., Jackson, A., Mikhail, J., & Persse, D. (2016). Telehealth-enabled emergency medical services program reduces ambulance transport to urban emergency departments. Western journal of emergency medicine, 17(6), 713.

5. Kneebone, Elizabeth, and Garr, Emily. 2010. “The Suburbanization of Poverty: Trends in Metropolitan America, 2000 to 2008.” Metropolitan Opportunity Series. Brookings Institution, Metropolitan Policy Program. http://www.brookings.edu/~/media/research/files/papers/2010/1/20-poverty-kneebone/0120_poverty_paper.pdf.

6. Kneebone, Elizabeth, and Holmes, Natalie. 2015. “The Growing Distance Between People and Jobs in Metropolitan America.” Brookings Institution, Metropolitan Policy Program. http://www.brookings.edu/~/media/research/files/reports/2015/03/24-job-proximity/srvy_jobsproximity.pdf.

7. Allard, Scott W., and Sarah Charnes Paisner. "The rise of suburban poverty." (2016).

8. Kneebone, E. (2014). The growth and spread of concentrated poverty, 2000 to 2008-2012. The Brookings.

9. Frolik, C., & Tribune News Service. (2019, December 30). Ohio City to Launch MIH-CP Program to Cut Down on Frequent Flyers. Retrieved from https://www.emsworld.com/news/1223715/ohio-city-launch-mih-cp-program-cut-down-frequent-flyers.

10. JEMS. (2020). The Impact of Telehealth-Enabled EMS on Ambulance Transports - JEMS. [online] Available at: https://www.jems.com/2017/08/01/the-impact-of-telehealth-enabled-ems-on-ambulance-transports/ [Accessed 11 Jan. 2020].

11. Agarwal, G., Angeles, R., Pirrie, M., McLeod, B., Marzanek, F., Parascandalo, J., & Thabane, L. (2019). Reducing 9-1-1 emergency medical service calls by implementing a community paramedicine program for vulnerable older adults in public housing in Canada: a multi-site cluster randomized controlled trial. Prehospital Emergency Care, 1-12.

Top Blogs of 2020

Congratulations to all of the authors with the most popular posts of 2020! Here is the 2020 rundown:

1. Oral Nerve Blocks (5,904 views)  

The most popular post of 2020 is this useful review of oral nerve blocks by Vytas Karalius, 2019 grad Andrew Cunningham, and Cincinnati faculty Jeff Hill - a great tool that can help make some of the most frustrating ED cases much better for everyone involved. Special note that this is part III in the Nerve Blocks of the Head & Neck series - all of which are in the top 10.

Take home point:

For oral nerve blocks, use bupivacaine with epinephrine when available. Oral/dental pain can be immensely painful and compromise a patient’s quality of life. The longer you can provide pain relief until they receive definitive care, the better off they will be.

 2. Clinical Question: are we impeding our patients’ fracture healing by giving them NSAIDs? (3,851 views)  

No clear answer but a strong discussion of the available evidence in this physiology vs outcomes-based data question by Andra Farcas, 2019 grad Jessica Bode, and local EM trauma guru Matthew Levine. 

Take home point:

The evidence isn’t slam-dunk in either direction on whether using NSAIDs impedes the fracture healing process. My takeaway: if my patients have no other contraindications to using NSAIDs and if their pain is well-controlled with said medication, then I’m going to advise they can use it for a short term and advise them to seek medical attention if they’re still needing to use NSADs regularly a few weeks out.

3. Little Lungs, Little Differences: Initiating Emergency Department Mechanical Ventilation in the Pediatric Patient (2,573 views)  

Kids aren’t little adults but their lungs are little; Matt McCauley, 2019 grad and current NorthShore attending Jacob Stelter, and Lurie PICU attending Katie Wolfe review on mechanically ventilating kids.

Take home point:

In choosing initial ventilator settings, the key is decision and reassessment. Most modes of ventilation will work in most children. However, careful attention to what support you’re providing your patient with and what the results of that support are, is vital.

4. Facial Nerve Blocks (1,380 views)

The first entry in the Nerve Blocks of the Head & Neck series by Vytas Karalius, 2019 grad & current faculty Aaron Quarles, and Boston Children’s attending Ashley Foster. In this post we review anesthetizing the face - a great tool for some terrible situations.

Take home point:

 Viscous lidocaine should be used prior to oral nerve blocks – this will greatly increase the patients’ comfort, their ability to remain still, and ultimately, your success.

5. Occipital Nerve Block (1,210 views)

Andrew Rogers, 2019 grad and current faculty Aaron Quarles, and Montefiore EM headache expert Ben Friedman (COI: his brother was in my residency class) review one of my favorite nerve blocks, which I offer to any headache that could possibly be occipital neuralgia and am constantly impressed by how well it works.

Take home point:

Occipital nerve blocks using local anesthetics are particularly useful for occipital neuralgia or migraines. Remember to aspirate before injecting to ensure no blood or CSF is seen. Fanning while injecting will help to improve success with this procedure. 

6. A Practical Approach to Abdominal Imaging (899 views)  

Zach Schmitz, 2020 grad David Kaltman, and NU radiologist Samir Abboud review key questions in ED abdominal imaging.

Take home point:

When both appendicitis and kidney stone are reasonably high on the differential, CT with IV contrast is warranted as stones >3mm can often still be seen and missing an appendicitis could have worse repercussions for a patient than a small stone. When considering biliary pathology, right upper quandrant ultrasound should be the first line imaging and is much more sensitive than CT for seeing gallstones, though sensitivity for cholecystitis is somewhat limited for both forms of imaging. Finally, pelvic ultrasound is considered first line imaging for female pelvic pain, but when intra-abdominal and ovarian pathology are of equal concern, a CT with contrast may be appropriate.

 7. The Timing of Antibiotics in Sepsis (526 views)

Jordan Maivelett, 2019 grad and current faculty Andrew Berg, and faculty/Lake Forest Hospital med director Tim Loftus dig into the data on time-to-antibiotics in sepsis, finding much less clarity than I expected.

Take home point

Early antibiotic initiating appears to improve mortality in sepsis and particularly in septic shock. However, not all patients meeting SIRS criteria are septic and some are sick from viral illness making it challenging to discern exactly when to start antibiotics. More data is needed to determine the right balance between early broad antibiotics and antibiotic stewardship.

 8. ED Boarding (491 views)

Julian Richardson, 2020 grad and admin fellow Luke Neill, and Tim Loftus review the intractable issue of ED boarding. It’s a big problem with a lot of issues, and more than anything, it is not an ED problem but rather a systemic problem that creates symptoms in the ED.

Take home point:

This is a complex medical issue. The most important factor leading to ED boarding is a lack of access to inpatient beds and there are multiple strategies we implement to try to solve this problem (fast tracks, observation units, etc.). Simply expanding an emergency department capacity is not effective. Boarding leads to adverse patient outcomes. Fixing this will involve collaboration among ED physicians, other specialties, hospital leadership and executives.

9. Marathon: the Collapsed Athlete (409 views)

Zach Schmitz, Andrew Berg, and sports fellowship-trained Jake Stelter summarize how to approach the collapsed distance runner.

Take home point:

While a relatively healthy cohort, endurance events can lead to a variety of life threatening scenarios. For a pulseless collapsed patient, ACLS should be initiated. Remember that a patient collapsing during exercise is typically more serious than after. For altered or syncopal patients, checking an EKG, sodium, glucose, and temperature are important first steps to rule out deadly pathology.

10. D-dimer How To (385 views)

Pete Serina, Laurie Aluce, and Timothy Loftus review the lab everyone loves to hate.

Take home point:

There are multiple different d-dimer assays, know which one your institution uses! You can use the PERC rule in low risk patients to rule out PE, but remember this test has its own pitfalls. If the patient is not PERC negative, Well’s criteria or other clinical scores can next be utilized to risk stratify. A d-dimer is appropriate for moderate risk patients. Remember that other etiologies can result in an elevated d-dimer other than PE and d-dimer can be adjusted based on a patient’s age.

Inhaled TXA

Written by: Jim O’Brien, MD (NUEM ‘23) Edited by: Kevin Dyer (NUEM ‘20) Expert Commentary by: Dion Tyler, PharmD

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Expert Commentary

Great job to the authors on providing a thorough description of TXA use in patients with hemoptysis. Another benefit of iTXA is that the IV TXA solution used for hemoptysis management is relatively inexpensive, ranging from $8.70-$86.80 per 100mg/mL (10 mL) vial [1]. 

An important consideration to note from the study conducted by Wand and colleagues is the exclusion of patients with massive hemoptysis defined as >200 mL of expectorated blood in 24 hours. As patients with massive hemoptysis may require additional emergent procedures to secure hemostasis such as bronchial artery embolization (BAE) or surgical intervention, a gap in knowledge exists whether TXA would be as effective in these patients as monotherapy or as an adjunct to the interventional therapies mentioned above [2,3]. 

An additional observational study has been recently published evaluating the use of iTXA for pulmonary hemorrhage in 19 critically ill pediatric patients. Pulmonary hemorrhage was caused by a variety of etiologies, with the most common etiology being diffuse alveolar hemorrhage. TXA was administered via inhalation or direct endotracheal instillation using the 100 mg/mL intravenous solution over 15-20 minutes. The dosing ranged from 250-500mg every 6-24 hours, with the most common regimen utilizing 250mg/dose every 8 hours. The study found that 18/19 (95%) of the patients demonstrated improvements in hemoptysis after the first dose of TXA and achieved cessation of pulmonary hemorrhage within 48 hours of iTXA administration. The only patient who did not have cessation of pulmonary hemorrhage was a patient on ECMO receiving systemic anticoagulation with unfractionated heparin. The median days of bleeding after TXA was initiated, days of TXA therapy received, total doses of TXA received, and cumulative dose of TXA received were 1 day, 3 days, 7 doses, and 2,500mg, respectively. Patients also received significantly less blood product transfusions after receiving iTXA (480 vs. 29.5 mL/kg; p=0.034). The study compared survivors with nonsurvivors but did not note any significant differences in the above outcomes between the two groups. There were no major adverse effects of iTXA or instances of bronchospasm reported in this study, and iTXA did not affect ventilatory settings for mechanically-ventilated patients. This study was limited by its retrospective design and lack of control group [4]. 

iTXA appears to be a safe, effective, and inexpensive intervention for management of hemoptysis. Additional research is required to determine optimal dosing and delivery approaches, as well as evaluate its safety and efficacy in patients with massive hemoptysis who may require additional emergent interventions and individuals receiving systemic anticoagulation or antiplatelet therapies.

References

1. Tranexamic acid. Lexi-Drugs. Hudson, OH: Lexicomp, 2020. http://online.lexi.com/. Accessed July 26, 2020.

2. Wand O, Guber E, Guber A, et al. Inhaled tranexamic acid for hemoptysis treatment: A randomized controlled trial. Chest. 2018; 154:1379–1384.

3. Davidson K, Shojaee S. Managing massive hemoptysis. Chest. 2020;157(1):77-88.

4. O’Neil ER, Schmees LR, Resendiz K, et al. Inhaled tranexamic acid as a novel treatment for pulmonary hemorrhage in critically ill pediatric patients: an observational study. Critical Care Explorations. 2020;2(1):e0075.

Dion Tyler, PharmD

Emergency Medicine Pharmacy Specialist

Sinai Health System

Chicago, IL

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How To Cite This Post:

[Peer-Reviewed, Web Publication] O’Brien, J. Dyer, K. (2020, Dec 21). Inhaled TXA. [NUEM Blog. Expert Commentary by Tyler, D]. Retrieved from http://www.nuemblog.com/blog/iTXA.

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Other Posts You May Enjoy

Antiemetics/Gastroparesis

Written by: Nery Porras, MD (NUEM ‘21) Edited by: Terese Wipple (NUEM ‘20) Expert Commentary by: Howard Kim, MD, MS

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The rise of Haloperidol as an antiemetic and analgesic in Gastroparesis

Nausea and vomiting is one the most common reasons for Emergency Department visits with estimated 2.5 million ED visits a year. Treatment of nausea and vomiting can be difficult because of its numerous causes. This is illustrated by the various sources of input that feed into the central emesis center in the brainstem, including the chemoreceptor trigger zone, vagus nerve, vestibular apparatus, and splanchnic afferent nerves, among others. Within these communication networks, various neurotransmitters such as dopamine, acetylcholine, histamine and serotonin are used, leading to the numerous drugs created to treat nausea and vomiting. Among these neurotransmitters, dopamine is becoming a more effective treatment target for nausea and vomiting among certain patient populations, in particular those with gastroparesis.

Gastro-pa-what?

Gastroparesis was something I did not recall learning much about in medical school, but is a diagnosis Emergency Medicine physicians will inevitably encounter and can be frustrating to treat. By definition, gastroparesis is a syndrome of delayed gastric emptying without evidence of mechanical obstruction leading to primary symptoms of nausea, vomiting, bloating, and abdominal pain. These patients have high rates of ED utilization and are difficult to treat, often leading to hospital admission. Traditional antiemetics often do not effectively work for these patients and narcotics only worsen the pseudo-obstruction causing their symptoms. This is where the dopamine receptor pathway can be an effective target for treatment in these patients.

Antipsychotics? You must be crazy?

As a junior resident I was surprised the first time one of my senior residents mentioned haloperidol as an effective antiemetic and analgesic in patients, particularly those with functional abdominal pain and gastroparesis. Indeed, a similar medication, Droperidol had been effectively used for many years for treatment of headache, agitation, and nausea. This was until a black box warning by the FDA in 2001 for concern for QT prolongation and cardiac dysrhythmias led to its decline in use and the halt of its manufacturing in the US. However, in 2015 the American Academy of Emergency Physicians published a position statement regarding the safety of droperidol in the Emergency Department stating “droperidol is an effective and safe medication in the treatment of nausea, headache and agitation.” Haloperidol, a butyrophenone similar to Droperidol, has been used to treat nausea and vomiting in palliative care and post-operative settings. It also has some analgesic effects due to its isometric similarity to meperidine. For this reason, it has been used off-label and anecdotally for nausea, vomiting and abdominal pain in the Emergency Department. Recently there have been two articles published showing Haloperidol efficacy in the treatment of Gastroparesis [1,4]:

“Haloperidol Undermining Gastroparesis (HUGS) in the Emergency Department”

This was a retrospective case matched observational study of patients with known gastroparesis secondary to diabetes. Patients receiving 5mg IM Haloperidol were compared to themselves from a prior ED visit for the same symptoms in which they did not receive haldol. The study found statistically significant reduction in hospital admissions (5/52 [10%] vs 14/52 [27%] p-value 0.02) and reduction morphine-equivalents used (6.75 vs 10.75 p-value 0.009) with the use of Haloperidol. They also found a non-statistically significant, but likely clinically significant, reduction in ED length of stay (median 9.2 hours vs 25.4 hours p-value 0.128). There were no reported extrapyramidal side effects or cardiovascular complications, though this was a small study [2,5].

“Randomized Controlled Double-blind Trial Comparing Haloperidol Combined With Conventional Therapy to Conventional Therapy Alone in Patients With Symptomatic Gastroparesis”

This randomized controlled study ultimately enrolled 33 patients with previously diagnosed gastroparesis presenting with nausea, vomiting, and abdominal pain. Patients were randomized into receiving 5mg IV haloperidol vs placebo in addition to conventional therapy (traditional antiemetics and narcotics). The primary outcome was to look at pain and nausea reduction at 1 hour based on a visual analog scale. The haloperidol group had an average reduction in pain intensity of 5.37 points (p < 0.001) compared to 1.11 points in the placebo group (p = 0.11). The Haldol group also had an average reduction in mean nausea score of 2.70 points (p < 0.001) compared to 0.72 in the placebo group(p = 0.05). They also did a subgroup analysis of patients who did not receive opiates before intervention and still found similar reduction in pain and nausea. This study also found a decrease in rate of admission (26.7% vs 72% p = 0.009) and ED length of stay (4.8 and 9 hours p = 0.77).  There were no adverse events, but the sample size was again quite small [3,6]. 

To use or not to use?

Gastroparesis and other similar cyclic vomiting syndromes present a therapeutic challenge to Emergency Physicians. Droperidol had been an effective tool in the treatment of nausea and vomiting but fell out of favor due to a black box warning. Literature review, as demonstrated in the AAEM position statement, has shown that perhaps this warning is not applicable to the doses used in the Emergency Department. This perhaps has led to the increase use of the antipsychotic Haloperidol in similar situations. These two studies now provide evidence for what many emergency physicians were already noticing; Haloperidol is an effective and safe treatment for nausea, vomiting and abdominal pain in gastroparesis. Perhaps this evidence may be extrapolated to other cyclic vomiting syndromes and treatment of other functional abdominal pain in the future.

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Expert Commentary

This is a great review on the use of butyrophenones in the treatment of gastroparesis and other causes of cyclical vomiting, such as cannabinoid hyperemesis syndrome. Haloperidol is an excellent tool to keep in your back pocket for the occasional patient with intractable nausea/vomiting; providing effective symptom relief can be both satisfying for patients and gratifying for clinicians.

 “Droperidol” seems to be one of those magical words in emergency medicine that inevitably draws out a number of opinions on the Black Box warning and old war stories from the more seasoned physicians. The most recent generation of U.S. ED physicians were trained in the absence of droperidol, however U.S. manufacturing resumed in 2019 and some hospitals now have access to this mythical medication. In the end, I don’t think it is worthwhile to debate the relative merits of droperidol vs haloperidol because many ED physicians will only have access to one or the other on their hospital formulary, and we have had good success with haloperidol over the last decade or so.

Interestingly, both of the studies you cited used a 5mg IM or IV dose of haloperidol. In my anecdotal experience, smaller doses of haloperidol (e.g., 2mg IV) are also effective for the relief of intractable nausea/vomiting, in addition to migraine headaches and functional abdominal pain. To my knowledge, there is not a great comparative effectiveness study of various haloperidol dosing regimens.

One additional point that I would advise readers about is that ED patients are increasingly tech-savvy and tend to Google medicines that they are about to receive. Thus, I always first give the patient a disclaimer that if they look up the word “haloperidol” they will see that it is typically used as a psychiatric medicine for conditions such as schizophrenia. I mention that this is not the indication for which we are using the medication today, but rather that haloperidol happens to have very effective anti-nausea properties due to is effect on dopamine receptors in the part of the brain that regulates nausea. I give a similar disclaimer when prescribing tamsulosin to female patients with significant ureteral stone burden – reassuring them that we do not, in fact, think they have an enlarged prostate.    

In summary, I agree with you that haloperidol is an effective and often under-utilized treatment for intractable nausea/vomiting. As with everything in emergency medicine, it’s best to know multiple treatment modalities for common conditions so that we can adapt our response to specific situations or challenges as needed. Butyrophenones are a good treatment option for patients that do not respond to traditional anti-emetics, as are benzodiazepines and anti-histamines. 

Howard Kim, MD, MS

Assistant Professor

Department of Emergency Medicine
Center for Health Services & Outcomes Research

Northwestern University Feinberg School of Medicine

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How To Cite This Post:

[Peer-Reviewed, Web Publication] Porras, N. Whipple, T. (2020, Dec 14). Anti-emetics/Gastroparesis. [NUEM Blog. Expert Commentary by Kim, H]. Retrieved from http://www.nuemblog.com/blog/antiemetics-gastroparesis

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Other Posts You May Enjoy

References

1. Perkins, Jack, et al. “American Academy of Emergency Medicine Position Statement: Safety of Droperidol Use in the Emergency Department.” The Journal of Emergency Medicine, vol. 49, no. 1, 2015, pp. 91–97.

2. Ramirez, Rene, et al. “Haloperidol Undermining Gastroparesis Symptoms (HUGS) in the Emergency Department.” The American Journal of Emergency Medicine, vol. 35, no. 8, 2017, pp. 1118–1120.

3. Roldan, Carlos J., et al. “Randomized Controlled Double-Blind Trial Comparing Haloperidol Combined With Conventional Therapy to Conventional Therapy Alone in Patients With Symptomatic Gastroparesis.” Academic Emergency Medicine, vol. 24, no. 11, 2017, pp. 1307–1314.

4. Weant, Kyle A. et al. “Antiemetic Use in the Emergency Department.” Advanced Emergency Nursing Journal, vol. 39, no. 2, 2017.

5. “Diabetic Gastroparesis Needs HUGS.” R.E.B.E.L. EM - Emergency Medicine Blog, 29 Nov. 2017, rebelem.com/diabetic-gastroparesis-needs-hugs/.

6. “SGEM#196: Gastroparesis – I Feel Like Throwing Up.” The Skeptics Guide to Emergency Medicine, 11 Dec. 2018, thesgem.com/2017/11/sgem196-gastroparesis-i-feel-like-throwing-up/.

Ultrasound Guidance for Lumbar Puncture

Written by: Maurey Hajjar, MD, MPH (NUEM ‘22) Edited by: Justin Seltzer, MD (NUEM ‘21) Expert Commentary by: Alex Ireland, MD (NUEM '20)

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Expert Commentary

Thank you to Dr. Hajjar and Dr. Seltzer for their excellent review of an underutilized ultrasound procedure. 

After several challenging lumbar punctures during my residency training, I began to adopt this technique as a supplemental tool to improve first-pass success. When beginning, the patient can be placed in either the lateral decubitus or the upright position. However, I have found that in the patients for whom you are looking for ultrasound guidance, the anatomy due to body habitus is already challenging, and upright positioning offers the best advantage of maintaining midline.

There are several approaches to identifying your target with ultrasound, and my preferred strategy is different than the one mentioned in this post. After palpating the bilateral anterior superior iliac spines and drawing lines inward towards the midline, I start with my probe in the transverse view to identify the spinous processes at L3, L4, and L5. I mark above and below my probe at each process to identify the midline.

I then rotate the probe 90 degrees into a longitudinal view, but I keep my probe in the midline to identify contiguous vertebral spinous processes and the intervertebral or interspinous spaces between them. I place a mark on both sides of my probe with it aligned in the middle of this intervertebral space, which will be the exact insertion point of my needle.

Another key advantage of ultrasound is the ability to measure the anticipated depth of needle insertion. After identifying the spinous processes and intervertebral space in longitudinal view, I increase the depth and the gain to view the mixed echogenicity soft tissue and ligaments, and then see the hypoechoic subarachnoid space underneath the dura mater. I measure the depth of this space and then have an estimate of how far to insert the needle before obtaining cerebrospinal fluid.

Lastly, I would highly recommend attempting this technique on several “easy” patients where you can also readily palpate the anatomy. Similar to using a bougie during difficult intubations, we need to be skilled with our rescue techniques through diligent preparation and repeated practice.

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References

Ultrasound Guided Lumbar Puncture. MGH Ultrasound. 

https://www.youtube.com/watch?v=DbqETxLurS0

 http://www.emdocs.net/ultrasound-lumbar-puncture-maximize-first-pass-success-patients-large-body-habitus/

Alex Ireland, MD

Emergency Medicine Physician

Vituity Group

Chicago, IL

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How To Cite This Post:

[Peer-Reviewed, Web Publication] Hajjar, M. Seltzer, J. (2020, Dec 7). Ultrasound Guidance for Lumbar Puncture. [NUEM Blog. Expert Commentary by Ireland, A]. Retrieved from http://www.nuemblog.com/blog/ultrasound-imaging-for-lumbar-puncture

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Other Posts You May Enjoy

Drug Interactions

Written by: Trish O’Connell, MD (NUEM ‘22) Edited by: Will Ford (NUEM ‘19) Expert Commentary by: Dion Tyler, PharmD and Bayan Al-Namnakani, PharmD

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Expert Commentary

IM olanzapine + IM/IV benzodiazepines: The FDA-approved package insert for olanzapine currently recommends general avoidance of intramuscular olanzapine and parenteral benzodiazepines [1]. The European Medicines Agency (EMA) recommends waiting > 1 hour following IM olanzapine administration to administer benzodiazepines with careful monitoring for excessive sedation and cardiorespiratory depression, likely taking into account the 15-45 minute time to reach peak concentrations for IM olanzapine [2]. 

The warning against coadministration of intramuscular olanzapine and benzodiazepines (BZDs) arose from postmarketing data of adverse events in patients receiving intramuscular olanzapine for acute agitation [3]. This study reported that BZD use was associated with 51.7% (15/29) of fatal cases and 85.7% (24/28) of serious adverse drug reactions, defined as those that were life-threatening, extended the hospital stay, or resulted in a permanent disability. The authors thus recommended that the combination of IM olanzapine and benzodiazepines be avoided in the absence of further prospective data. However, it is important to note that many of these patients in this cohort had severe comorbidities, and BZD association included all instances (oral, IV, or IM) of BZD administration throughout their hospital stay. Some patients expired several days or weeks following their last olanzapine dose, making a causal association difficult to determine. Subsequent, smaller cohorts have found that oxygen desaturations are greatest in individuals who receive olanzapine and BZD therapy and have consumed ethanol, yet desaturation rates were similar with this combination in patients without ethanol intoxication when compared to olanzapine and haloperidol monotherapy as well as haloperidol and BZD combination therapy [4,5]. A retrospective, medication use evaluation (MUE) of IM olanzapine and lorazepam also demonstrated no incidences of hypotension or oxygen desaturation when the combination was administered within 1-hour or 24-hours of each other [6].  Lastly, a prospective cohort of individuals receiving IV olanzapine or IV droperidol followed immediately by IV midazolam compared with IV midazolam alone also demonstrated similar rates of oxygen desaturations and adverse events among all three groups [7]. However, IV olanzapine is not approved for use in acute agitation, and may display different pharmacokinetics compared to IM administration. 

While evidence supporting the safe use of this combination is growing, it may be prudent to use caution while coadministering IM olanzapine and BZDs in the absence of further controlled studies and in patients at greatest risk for adverse events, including the elderly and those who’ve consumed ethanol. 

References:

1. Olanzapine [package insert]. Indianapolis, IN: Eli Lilly and Company, 2010.

2. Zyprexa. European Medicines Agency. https://www.ema.europa.eu/en/medicines/human/EPAR/zyprexa. Accessed June 28, 2020.

3. Marder SR, Sorsaburu S, Dunayevich E, et a.l. Case reports of postmarketing adverse event experiences with olanzapine intramuscular treatment in patients with agitation. J Clin Psychiatry. 2010;71(4):433-41.

4. Wilson MP, MacDonald K, Vilke GM, et al. Potential complications of combining intramuscular olaznapine with benzodiazepines in emergency department patients. J Emerg Med. 2012;43(5):889-96.

5. Wilson MP, MacDonald K, Vilke GM, et al. A comparison of the safety of olanzapine and haloperidol in combination with benzodiazepines in emergency department patients with acute agitation.  J Emerg Med. 2012;43(5):790-97.

6. Williams AM. Coadministration of intramuscular olanzapine and benzodiazepines in agitated patients with mental illness. Ment Health Clin. 2018;8(5):208-13.

7. Chan EW, Taylor DM, Knott JC, et al. Intravenous droperidol or olanzapine as an adjunct to midazolam for the acutely agitated patient: a multicenter, randomized, double-blind, placebo-controlled clinical trial. Ann Emerg Med. 2013;61:72-81. 

Myasthenia gravis and medications in the emergency department: Myasthenia gravis (MG) is an autoimmune disorder resulting in destruction of acetylcholine receptors at the neuromuscular junction (NMJ) and resultant muscular weakness. While not included in the original blog post, this is a drug-disease interaction where pharmacy services are frequently recruited for assistance in choosing medications that will not cause or exacerbate a myasthenic crisis. Although not all-inclusive, common agents that may be frequently encountered in the ED are listed below [1-3]:

• Neuromuscular blocking agents (paralytics): Succinylcholine exerts its therapeutic effects through depolarization of the acetylcholine receptor at the NMJ causing sustained paralysis. In the setting of MG and reduced acetylcholine receptors, succinylcholine requirements may be increased, necessitating a higher dose of 1.5-2 mg/kg. Conversely, MG patients are more sensitive to nondepolarizing neuromuscular blockers,such as rocuronium and vecuronium, requiring a lower dose than normal. For rocuronium, a dose of 0.3-0.6 mg/kg may be considered for these patients.

• Antibiotics: Several classes of antibiotics have been shown to prevent transmission of acetylcholine to the acetylcholine receptor at varying levels of risk listed below:

  • High risk: aminoglycosides, fluoroquinolones

  • Medium risk: Macrolides, polymixin B

  • Low risk: Penicillins, cephalosporins, carbapenems, nitrofurantoin, clindamycin, sulfonamides, doxycycline

• Magnesium: Magnesium interferes with release of acetylcholine to the NMJ and may exacerbate a myasthenic crisis. A  higher threshold for repletion may be necessary in MG patients as well as avoidance of use for migraines, tachyarrhythmias, and as a component of laxatives.

• Beta blockers: Beta blockers also appear to have an effect at the NMJ in preventing acetylcholine transmission, and have been found to exacerbate MG symptoms in patients with a variety of different agents in the class and routes of administration, such as ophthalmic timolol. 

• Corticosteroids: While frequently used as treatment for a MG crisis, these agents may paradoxically worsen muscle strength through acetylcholine receptor blocking and effects on muscle contractility. 

References:

1. Roper J, Fleming ME, Long B, et al. Myasthenia gravis and crisis: evaluation and management in the emergency department. J of Emerg Med. 2017;53:843-53.

2. Ahmed A, Simmons Z. Drugs which may exacerbate of induce myasthenia gravis: a clinician’s guide. The Internet Journal of Neurology. 2008;10:e1-8.

3. Singh P, Idowu O, Malik I, et al. Acute respiratory failure induced by magnesium replacement in a 62-year-old woman with myasthenia gravis. Tex Heart Inst J. 2015;42(5):495-97.

Lithium + ibuprofen (NSAIDs): Treatment with lithium could be quite challenging due to its extremely narrow-therapeutic index (0.5–1.2 mEq/L). Therefore, minor changes affect serum levels. The most common lithium poisoning occurs unintentionally (with chronic use) when the lithium intake exceeds its elimination such as in impaired kidney function or due to drug-drug interaction.1

Lithium is a water-soluble monovalent cation widely distributed in the body and it goes complete glomerulus filtration, 75 % of the ion is reabsorbed mainly in the proximal tubule. The exact mechanism is not fully understood. It appears that NSAIDs decrease the eGFR resulting in decreased lithium renal excretion. Some experts hypothesized that this is a result of the prostaglandin synthesis inhibition by NSAIDs which may lead to low renal blood flow and facilitate the reabsorption of sodium and lithium (theoretically). However, this hasn’t been proven [1].

This interaction is well known in clinical practice and most providers will be cautious when it comes to NSAIDs. Small prospective studies have shown large interindividual differences in lithium clearance associated with different NSAIDs. Those effects are highly variable and less predictable. It can occur with any NSAID and studies haven’t concluded a strong relationship with a specific agent. They have reported a reduction in lithium level by 10-25% in healthy volunteers [1-2], and up to 60% in another study [3]. A small retrospective study quantified the relative risk of lithium toxicity secondary to a medication new start in elderly patients who are on lithium. The relative risk was dramatically higher with ACEIs (RR=7.6, 95% CI=2.6–22.0) and loop diuretics (RR=5.5, 95% CI=1.9–16.1). Interestingly, NSAIDs and thiazides were not independently associated with increased risk of lithium toxicity [5].

Lithium levels and toxic effects should be monitored with concomitant NSAIDs initiation. Consider lithium dose reduction especially with NSAIDs new start or dose increase.

References: 

1. Finley, P.R. Drug Interactions with Lithium: An Update. Clin Pharmacokinet 55, 925–941 (2016).

2. Reimann IW, Diener U, Frölich JC. Indomethacin but not aspirin increases plasma lithium ion levels. Arch Gen Psychiatry. 1983;40(3):283–6.

3. Ragheb MA. Aspirin does not significantly affect patients’ serum lithium levels. J Clin Psychiatry. 1987;48(10):425.

4. Ragheb M. Ibuprofen can increase serum lithium level in lithium-treated patients. J Clin Psychiatry. 1987;48(4):161–3.

5. Juurlink, D.N., Mamdani, M.M., Kopp, A., Rochon, P.A., Shulman, K.I. and Redelmeier, D.A. (2004), Drug‐Induced Lithium Toxicity in the Elderly: A Population‐Based Study. Journal of the American Geriatrics Society, 52: 794-798. doi:10.1111/j.1532-5415.2004.52221.x.

Nitroglycerin (NTG) and inferior MI: Great job to the authors on describing an interaction that comes up quite frequently in the emergency department. The ACC/AHA guidelines on acute STEMI recommend avoidance of NTG in patients with RV dysfunction, pre-existing hypotension, marked bradycardia or tachycardia, and use of phosphodiesterase-5 inhibitor (PDE5) use in the previous 24-48 hours [1]. Specifically, 24 hours should elapse following sildenafil use, and 48 hours following tadalafil use, due to the difference in pharmacokinetics between these PDE5s [2,3]. 

It appears that this recommendation has been challenged by a retrospective analysis conducted by Robichaud and colleagues assessing the incidence of hypotension in prehospital patients with inferior STEMI and acute chest pain receiving NTG compared with those who did not receive NTG [4]. The determination of STEMI was made by a computer-interpreted electrocardiogram (ECG) utilized by EMS while in the prehospital setting. The researchers found similar rates of hypotension between the two groups, but stated that a computer-interpreted ECG cannot be used as the sole predictor for patients who may be predisposed to hypotension following NTG administration. In the absence of controlled data, it may be necessary to exercise caution when considering NTG in STEMI patients with known RV involvement and avoid use in hypotensive patients. 

References:

1. O'Gara PT, Kushner FG., Ascheim DD, et al. 2013 ACCF/AHA guideline for the management of ST-elevation myocardial infarction: A report of the American College of Cardiology Foundation/American Heart Association Task Force on practice guidelines. Circ. 2013;127:e362-e425.

2. Sildenafil [package insert]. New York, NY: Pfizer Labs, 2014.

3. Tadalafil [package insert]. Indianapolis, IN: Eli Lilly and Company, 2018.

4. Robichaud L, Ross D, Proulx M, et al. Prehospital nitroglycerin safety in inferior ST elevation myocardial infarction, Prehosp Emerg Care. 2016;20(1):76-81.

Dion Tyler, PharmD

Emergency Medicine Pharmacy Specialist

Sinai Health System

Chicago, IL

Bayan Al-Namnakani, PharmD

PGY-2 Emergency Medicine Clinical Fellow

Northwestern Memorial Hospital Pharmacy

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How To Cite This Post:

[Peer-Reviewed, Web Publication] O’Connell, T. Ford, W. (2020, Nov 29). Drug Interactions. [NUEM Blog. Expert Commentary by Tyler, D. Al-Namnakani, B]. Retrieved from http://www.nuemblog.com/blog/drug-interactions.

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Other Posts You May Enjoy

Elderly Fallers

Written by: Nick Wleklinski, MD (NUEM ‘22) Edited by: Kumar Gandhi, MD, MPH (NUEM '20) Expert Commentary by: Scott Dresden, MD, MS

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Oh How the Older Adults Fall

Introduction:

Older adults (>65yrs old) fall. In 2006, older adult patients who fell made up approximately 2.1 million of ED visits totaling $6.1 billion in health care dollars [1]. Falls are the most common cause of unintentional injury for older folks, accounting for 13% of all ED visits from 2008-2010 [2]. These numbers are only increasing as our population ages and it is predicted to double by 2030 [3]. The injuries incurred wildly vary, but these patients tend to fall into two buckets: Major injury/organic etiology à admit vs. simple mechanical fall à Discharge.

Common injuries requiring hospitalization:

Falls resulting in major injury carry significant morbidity and mortality. Hip fractures lead to deterioration in function and carry ~27% mortality at 1 year [4]. Head injuries account for a significant amount of fall-related deaths, making CT brain imagining imperative in most fall patients. Add a CT C-spine as these injuries are more common in the older adults, the Canadian and Nexus C-spine rules don’t work well for these patients [5]. Additionally, rib fractures are common and require significant analgesia to prevent splinting and subsequent complications. Be sure to consider blunt cardiac injury and pulmonary contusion! Given that falls are a frequent cause of trauma in older adult patients, it is important to keep the effects of aging in mind when running the ABC’s (Table 1) [6].

Table 1: Further considerations for ABC’s in older adult trauma patients.

The tougher scenario: Those without any injuries:

Patients without any major injuries deserve more thought than simply ruling out organic etiologies (i.e. CVA, ACS, arrythmia, etc.) and major trauma. These patients are at high risk for subsequent falls and may even have underlying physiologic injuries. Using the term “mechanical fall” is risky as it can anchor providers into comfort. Therefore, having a more regimented approach can help better risk stratify these patients.

The fall itself:

• Where did it happen?

  • Those in nursing homes/institutional setting fall more frequently than those in the community (60% vs ~33%, respectively) [7]

  • Falls at home should trigger need for home safety evaluation

• Have you fallen before?

  • History tends to repeat itself, with nearly 50% of fallers falling again within 1 year [8]

• Witnessed vs Unwitnessed?

  • Collateral information can provide key details if a patient is a fall risk and requires further evaluation by physical therapy

• How long where you on the ground? [9, 10]

Figure 1: Increased time on the ground leads to worsening fall anxiety and increased risk of rhabdomyolysis and subsequent kidney injury

Evaluating the patient:

• Outside of the obvious (CVA, ACS, etc.), it is important to also consider other common etiologies:

  • Hypotension

  • Arrythmias

  • Infection (PNA, UTI, pressure ulcers)

  • Vestibular dysfunction (i.e. BPPV)

  • Anemia

    • Ask about melena as this is a commonly not investigated [11]

  • Delirium

  • Malignancy

•  Medications: Polypharmacy is a known issue in older adults, but there are certain medications to take note of. Antidepressants and antipsychotics are associated with the highest risk of falls while diuretics and narcotics didn’t have as much of a risk (Table 2) [12]. Additionally, who manages the meds and how are they organized at home?

Table 2: Common medications associated with falls

• What is their baseline? This is the meat and potatoes of the evaluation and where future risk factors can be identified and addressed.

  • How steady do they feel on their feet?

  • Decreased cognition (Dementia, Alzheimer’s, etc.) incurs increase fall risk [13]

  • Do they have arthritis/chronic pain?

    • Can result in unsteady gait from favoring certain part of body, increasing risk

  • Timed Up and Go Test:

    • A great way to evaluate lower extremity strength and balance (figure 2)

  • Visual and auditory impairment: Visual acuity should be addressed. Look at their eyewear as multifocal lenses increase fall risk [14].

  • Feet: check for neuropathy and ask about footwear.

  • Assist devices used for ambulation? Do they use these devices regularly and correctly?

  • Delirium screening

    • The Confusion Assessment Method is used in triage [15]

Figure 2: The Timed Up and Go Test.

Things we can do:

Although continuity is not generally part of the EM specialty, we can help address future fall risk for these patients who we discharge after their fall evaluation. Recommending supplements such as vitamin D and calcium are helpful for reducing risk for fall-related injuries [7]. Balance training through outpatient physical therapy referrals can further help reduce fall risk. Follow up is imperative and these patients should see their PMD or a geriatrician soon after their discharge from the ER to continue their fall evaluation.  

Conclusion:

While major trauma from falls is exciting and straight forward, it is important to give more thought to those older adult patients deemed to have a “mechanical fall”. Gathering information about the fall and determining the patient’s baseline can help stratify future risk. The incidence of falls is only going to increase as our population ages, so having a regimented approach to these patients is imperative.

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Expert Commentary

As was expertly described, falls in older adults lead to significant morbidity and mortality.  Unfortunately, in the ED they are often dismissed as “mechanical,” the injuries are treated, but the causes are never identified. The term mechanical fall is ambiguous and unhelpful and should not be used in the ED. Some mean that the fall was not a result of seizure or syncope, but it is not a clear term.  Additionally, it does not help with prognosis. There are no differences in adverse events at 6 months between “mechanical” and non-mechanical faller. For a great discussion of the Myth of the Mechanical Fall see Shan Liu’s presentation at IGNITE presentation at SAEM18 (https://saem-ondemand.echo360.org/media-player.aspx/5/13/431/1608).

Even if injuries are minor, patients often do poorly. Between 36% and 50% of patients have an adverse event such as a recurrent fall, emergency department revisit, or death within 1 year after a fall, including 25% who die within 1 year. As the CDC likes to remind us, every 20 minutes someone dies from a fall (https://www.cdc.gov/steadi/index.html).

So what do we do with this medical problem that has a 25% 1-year mortality? As with many problems in geriatrics, falls are a sentinel event, and deserve a sentinel response. It is our job to prevent the next fall. The Geriatric Emergency Department Guidelines provide a framework for a risk assessment after a fall. One might think that the cause of the fall is obvious (e.g. tripped over a crack in the sidewalk). However a thoughtful assessment begins by asking “if this patient was a health 20-year-old, would he or she have fallen? “ If the answer is no, then the assessment of the underlying cause of the fall should be more comprehensive and should include a thorough history of the fall and risk factors such as ability to perform Activities of Daily Living (ADLs), appropriate footwear, and medications. Physical exam should include orthostatic blood pressure, a head to toe exam even for patients with seemingly isolated injuries, a neurologic exam with special attention to neuropathy and proximal motor strength, and a safety assessment. Patients should be able to rise from the bed or chair, turn, and steadily ambulate in the ED before considering discharge (not while the nurse is handing the patient his or her discharge paperwork). For patients who are unable to safely ambulate, consideration of an assist device such as a cane or walker should be given, physical therapy (PT) and occupational therapy (OT) consultation, and possibly hospital admission.  All patients who are admitted after a fall should be admitted by PT and OT. Additionally, patients who fell should have home safety assessments which may be arranged through occupational therapy.

In addition to the GED guidelines, the CDC has developed the Stopping Elderly Accidents, Deaths & Injuries (STEADI) program. This program includes an algorithm for fall risk screening, assessment and intervention. For screening they recommend patients answer the Stay Independent screening (a 12 question tool), however if the patient is in the ED for a fall, this step can be omitted because the patient has already declared themselves as high risk for falls.  To evaluate gait, strength, and balance, the Timed Up & Go, 30-Second Chair Stand, or 4-Stage Balance Test are recommended. In addition, to the assessments mentioned previously (medications, orthostatics), asking about potential hazards such as throw rugs or slippery floors, and a visual acuity check are advised. Once risk factors are identified they should be addressed through physical therapy, exercise of fall prevention programs, medication optimization, home safety evaluation, discussion with outpatient clinicians regarding orthostatic hypotension, referral to a podiatrist for proper footwear, recommending a vitamin D supplement. Finally, ensuring close and enduring followup is important. Consider a referral to a geriatrician if the patient doesn’t already see one.

Scott Dresden, MD, MS

Associated Professor of Emergency Medicine

Director of Geriatric Emergency Department Innovations (GEDI)

Northwestern Memorial Hospital

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How To Cite This Post:

[Peer-Reviewed, Web Publication] Wleklinski, N. Gandhi, G. (2020, Nov 23). Elderly Fallers. [NUEM Blog. Expert Commentary by Dresden, D]. Retrieved from http://www.nuemblog.com/blog/elderly-falls.

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References

1. Owens, P.L., et al., Emergency Department Visits for Injurious Falls among the Elderly, 2006: Statistical Brief #80, in Healthcare Cost and Utilization Project (HCUP) Statistical Briefs. 2006, Agency for Healthcare Research and Quality (US): Rockville (MD).

2. Sapiro, A.L., et al., Rapid recombination mapping for high-throughput genetic screens in Drosophila. G3 (Bethesda), 2013. 3(12): p. 2313-9.

3. Foundation, C.f.D.C.a.P.a.T.M.C. The State of Aging and Health in America 2007. 2007  [cited 2019.

4. Cenzer, I.S., et al., One-Year Mortality After Hip Fracture: Development and Validation of a Prognostic Index. J Am Geriatr Soc, 2016. 64(9): p. 1863-8.

5. Goode, T., et al., Evaluation of cervical spine fracture in the elderly: can we trust our physical examination? Am Surg, 2014. 80(2): p. 182-4.

6. Carpenter, C.R., et al., Major trauma in the older patient: Evolving trauma care beyond management of bumps and bruises. Emerg Med Australas, 2017. 29(4): p. 450-455.

7. Nagaraj, G., et al., Avoiding anchoring bias by moving beyond 'mechanical falls' in geriatric emergency medicine. Emerg Med Australas, 2018. 30(6): p. 843-850.

8. Liu, S.W., et al., Frequency of ED revisits and death among older adults after a fall. Am J Emerg Med, 2015. 33(8): p. 1012-8.

9. Austin, N., et al., Fear of falling in older women: a longitudinal study of incidence, persistence, and predictors. J Am Geriatr Soc, 2007. 55(10): p. 1598-603.

10. Deshpande, N., et al., Activity restriction induced by fear of falling and objective and subjective measures of physical function: a prospective cohort study. J Am Geriatr Soc, 2008. 56(4): p. 615-20.

11. Tirrell, G., et al., Evaluation of older adult patients with falls in the emergency department: discordance with national guidelines. Acad Emerg Med, 2015. 22(4): p. 461-7.

12. Woolcott, J.C., et al., Meta-analysis of the impact of 9 medication classes on falls in elderly persons. Arch Intern Med, 2009. 169(21): p. 1952-60.

13. Muir, S.W., K. Gopaul, and M.M. Montero Odasso, The role of cognitive impairment in fall risk among older adults: a systematic review and meta-analysis. Age Ageing, 2012. 41(3): p. 299-308.

14. Lord, S.R., J. Dayhew, and A. Howland, Multifocal glasses impair edge-contrast sensitivity and depth perception and increase the risk of falls in older people. J Am Geriatr Soc, 2002. 50(11): p. 1760-6.

15. Han, J.H., et al., Diagnosing delirium in older emergency department patients: validity and reliability of the delirium triage screen and the brief confusion assessment method. Ann Emerg Med, 2013. 62(5): p. 457-465.

The BICAR-ICU Trial and Practical Use of Bicarb in Metabolic Acidosis

Written by: Philip Jackson, MD (NUEM ‘20) Edited by: Katie Colton, MD (NUEM ‘19) Expert Commentary by: Benjamin Singer, MD

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Introduction

 Until recently, there has been a paucity of high-quality data to inform the use of intravenous sodium bicarbonate in severe metabolic acidosis.  This has resulted in a lack of universal practice guidelines to inform clinicians in emergency medicine and other specialties when caring for some of their sickest patients.

 Historically there have been two camps of thought when approaching the use of sodium bicarbonate in the sick, acidotic patient.  Severe acidemia results in protein dysfunction, potentially leading to arrhythmia, cardiovascular collapse, multi-organ failure and eventual death. [1-6] Thus, correcting acidemia with alkalotic bicarbonate solutions could prevent these compounding complications.  However, growing evidence suggests that the deleterious effects associated with profound acidemia may be more strongly associated with the underlying physiological insult than the acidosis itself.  Therefore, treating the acidemia without addressing the underlying pathology may expose the patient to side effects including hypernatremia, hypocalcemia, and exacerbation of CNS cellular acidosis (due to increased levels of carbon dioxide) without resulting in a net benefit. [1,2]

The BICAR-ICU Trial

 A recent randomized, prospective, multi-center trial by Jaber et al. evaluated the effects of bicarbonate administration to ICU patients with metabolic acidemia. The study randomized 389 ICU patients with severe metabolic acidemia (pH ≤7⋅20, PaCO ≤45 mm Hg, and sodium bicarbonate concentration ≤20 mmol/L), a total Sequential Organ Failure Assessment score of 4 or more or an arterial lactate concentration of 2 mmol/L or more into a treatment group receiving 4.2% sodium bicarbonate (<1L per day) or a control group receiving an equivalent volume of standard crystalloid solution.

 There was no significant difference between the two groups in the primary outcome, a composite of all-cause mortality at day 28 and the presence of organ failure at day 7.  Interestingly, bicarbonate administration decreased the need for renal replacement therapy (RRT) and in a sub-group of patients with acute kidney injury bicarbonate infusion improved mortality and decreased vasopressor requirements.

 It is important to note that the study excluded patients with significant urinary or digestive tract losses of bicarbonate (two important causes of non-anion gap metabolic acidosis) and patients that had already been treated with bicarbonate or RRT. Furthermore, a significant proportion of patients in the control group (24%) received bicarbonate at some point during the study and only 60% of the treatment group actually maintained the goal pH of >7.30. These factors skew the study towards a negative outcome, as they presumably blunt the effects of administration of bicarbonate. Thus, it is possible that more of a benefit may have been observed without these disruptions.

 The study did not differentiate between etiologies of metabolic acidemia, though ketoacidosis was also excluded, and thus it is difficult to draw conclusions on the value of bicarbonate in various pathologic conditions. There was no specific protocol regarding timing of administration or concentration, making the study difficult to replicate in the emergency setting. Nevertheless, it was essentially the first large, multi-center RCT evaluating this topic and so some practical conclusions can be drawn; these should be interpreted in the context of each individual patient.

Practice recommendations in special situations

• Anion Gap Metabolic Acidosis: The human body maintains an essentially neutral net electrical charge through the retention and excretion of ions (notably H+) and anions (notably Cl- and HCO3-). Addition or retention of other anions will increase the anion gap and cause a net negative charge, causing retention of  H+ ions and leading to a metabolic acidosis. In general, administration of bicarbonate to this scenario will balance the pH but will not remove the additional anions that are the root cause of the pathologic acidosis and would presumably provide little benefit to patient outcomes.

• Lactic Acidosis: Previous to the BICAR-ICU trial, most available data suggests no benefit of bicarbonate. Notably two small prospective physiological studies of 14 and 10 patients, respectively, demonstrated no hemodynamic response or difference in response to catecholamines. [7,8]  Additional retrospective and observational studies did not result in clear conclusions. [9,10] The BICAR-ICU trial did not specifically evaluate this population and thus current guidelines recommend against bicarbonate administration unless pH falls below 7.15 or bicarbonate falls below 5 mEq/L (at which point small changes in bicarbonate concentration can lead to potentially fatal changes in pH). [11]

  • In general, DON’T GIVE IT

• Diabetic and Alcoholic Ketoacidosis: A prospective RCT of 21 patients in severe DKA showed no benefit of bicarbonate therapy. [12] Limited data in pediatric DKA and adult AKA populations show similar findings. [13,14] There is evidence that bicarb administration is associated with worse outcome in pediatric patients. It is feasible to give bicarbonate to patients in extremis (pH<6.9) in the adult population to theoretically prevent cardiovascular collapse.

  • In general, DON’T GIVE IT except when pH<6.9 and with extreme caution in the pediatric patient

•  Toxic Ingestions (methanol, ethylene glycol, toluene, salicylates, etc.): In general, along with specific therapies, bicarbonate infusion is a mainstay of therapy as systemic and urinary alkalinization removes these anions through ion trapping of metabolites. [15]

  • GIVE IT, along with specific antidotes and possible dialysis

•  Uremic Acidosis:  Uremic acidosis results from the inability of the injured kidney to excrete anions such as phosphates, sulfates, and nitrates and so removal of these substances is the mainstay of therapy. Administration of bicarbonate does not directly impact this end, and data supporting its use is limited. [16] However, it is the current practice of many nephrologists to treat uremic acidosis with bicarbonate infusion to prevent the need for RRT.  It is intuitive that bicarbonate can prevent RRT as bicarbonate therapy both corrects pH and also temporarily improves hyperkalemia (depending on the concentration of the solution). This was again demonstrated in the BICAR-ICU trial with a reduced need for RRT in the treatment group, as well as a mortality benefit in a subgroup with AKI. Though further investigation is needed, it is reasonable to give bicarbonate in this population in consultation with nephrology.

  • GIVE IT, judiciously in severe acidemia and in consultation with a nephrologist

• Non-Anion Gap Metabolic Acidosis: In general, this results from loss of total body bicarbonate or retention of additional chloride. It is thus, theoretically reasonable to treat this population with bicarbonate because you are directly addressing the underlying pathophysiology. [1,2]

•  Renal Losses, including Renal Tubular Acidosis (RTA): Several types exist, but the pathophysiology lies in the inability of the kidneys to re-absorb bicarbonate resulting in increased urinary losses. The mainstay of therapy is bicarbonate, both oral and IV if severe. [17]

  • GIVE IT

•  Gastrointestinal Losses (pancreatic fistula, diarrhea, uretal diversion, etc.): Excessive loss of bicarbonate through the GI tract causes a systemic acidosis. Removing the offending pathology (repairing the fistula) is the mainstay of therapy with bicarbonate replacement as a temporizing measure. [18,19]

  • GIVE IT, in severe cases

• Hyperchloremic Metabolic Acidosis: Usually, as the result of iatrogenic over-administration of chloride rich fluids (normal saline). Therapy involves stopping administration of high chloride content fluids and/or switching to a more pH neutral solution such as Lactated Ringer’s or sodium bicarbonate in dextrose. [20,21]

  • GIVE IT, in severe cases

Conclusions

•   Administration of sodium bicarbonate is recommended along with therapies targeting specific etiologies of acidemia in severe cases of non-anion gap metabolic acidosis and anion gap metabolic acidosis secondary to most toxic ingestions.

•   Bicarbonate administration is reasonable in severe metabolic acidemia secondary to uremic acidosis and in patients with both AKI and acidemia.  Further research is needed to elucidate protocols and to clearly demonstrate benefits.

•   Bicarbonate administration is rarely recommended in both ketoacidosis and lactic acidosis unless the patient is in extremis as it has shown no clear benefit and may cause harm.

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Expert Commentary

In this trial there was no attempt to differentiate the cause of acidosis a priori, but the type of metabolic acidosis matters when considering bicarb administration. Why?

a) Metabolic acidosis without elevation in the anion gap is more likely to respond to bicarb administration than acidosis with an elevated anion gap. You can think of non-gap acidosis as bicarb deficiency; by administering bicarb, you are repleting bicarb.

b) The trial supports the use of bicarb for uremic acidosis, which tends to be a mix of non-gap- and gap-associated phenomena (renal tubular acidosis combined with an increase in unmeasured anions). Note that the number-needed-to-treat was six patients to prevent one of them from going on dialysis in the AKI subgroup.

c) Lactic acidosis is a misnomer in that the process that creates an elevation in blood lactate anions is physiologically separate from the process generating protons. [1,2] Lactate elevation occurs because of shunting of glycolysis-generated pyruvate away from oxidative metabolism and toward lactate production. This shunting can occur in states of hypoxia (oxidative metabolism shut down, usually Type A) or normoxia (so-called aerobic glycolysis, usually Type B). Lactate is a weak base, so why is there often an associated acidosis? The proton comes from hydrolysis of ATP, which cannot be rapidly replenished under conditions that also favor lactate production (e.g., hypoxia).

So, why does bicarb administration not work well for lactic acidosis? Because even if you titrate off those extra protons using huge amounts of bicarb, you will not rebalance hydrolysis and re-generation of ATP until you fix the underlying problem (ischemia, sepsis, etc.). The rationale for avoiding bicarb in ketoacidosis is similar. Hence, I agree with the recommendation to use bicarb in patients with severe non-uremic anion-gap-associated acidemia only as a temporizing measure while working to reverse the underlying cause.

References

1. Mizock BA. Controversies in lactic acidosis. Implications in critically ill patients. JAMA. 1987;258:497-501.

2. Andersen LW, Mackenhauer J, Roberts JC, Berg KM, Cocchi MN, Donnino MW. Etiology and therapeutic approach to elevated lactate levels. Mayo Clin Proc. 2013;88:1127-1140. PMCID: PMC3975915.

Benjamin Singer, MD

Assistant Professor of Medicine

Pulmonary and Critical Care

Biochemistry and Molecular Genetics

Northwestern University

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How To Cite This Post:

[Peer-Reviewed, Web Publication] Jackson, P. Colton, K. (2020, Nov 16). The BICAR-ICU Trial and Practical Use of Bicarb in Metabolic Acidosis. [NUEM Blog. Expert Commentary by Singer, B]. Retrieved from http://www.nuemblog.com/blog/BICAR-ICU-trial.

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