#FOAMed Digest No. 1: Total Eclipse of the Heart

Welcome to the very first edition of the WUEMR FOAMed Digest! The Social Media Committee hopes with this segment to parse out from the overwhelming FOAMed universe a few of the most high-yield pieces of highest relevance to the general EM trainee. We hope to deliver this in an easily digestible format that you can realistically work through over a week – even if you’re stuck in an ICU.

Each post will contain several sections:

1. Three Stars: Three of the best-of-the-best from the FOAMed world published in the past week or so.

2. Oldie But Goodie: The FOAMed universe has been around long enough that there’s already a good number of very well-done and highly informative blog posts and podcasts.

3. Free (For Now) Open Access Med Ed: F(FN)OAMed for short. There are some great resources out there that are not free to the vast majority of EM practitioners but, due to your EMRA membership being graciously covered via the residency and MoCEP, you have access to them. Most notably, your EMRA membership allows you subscription to the EM:RAP podcast and the EB Medicine resources – EM Practice, EM Critical Care, etc. You should take advantage of this opportunity while you can, and this section will help you do so. (Contact your friendly local Social Media Committee member if you need help setting up your access.)

4. The Gunner Files: The Social Media Committee recognizes that, with this being Wash U and all, some of you will always be overachieving. So we’ll include a few extra selections for those of you that have a more insatiable FOAMed appetite.

Without further ado, let’s kick the tires and light the fires.

This week, “Total Eclipse of the Heart,” will focus on care of various cardiac conditions.

Three Stars:

1. Ever heard of Wellens’ Syndrome? If you have any hope of passing your boards one day, you should. Not mention that whole “you shouldn’t miss a critical EKG finding that portends certain doom” thing. Never fear, Salim Reazie, author of the excellent R.E.B.E.L.-EM blog, has you covered. 

(Don’t miss the links list at the bottom that highlights posts from other top-notch FOAMed resources!)

2. Syncope is one of those presenting complaints that really must be approached in a systematic manner. The grandmaster of EM EKG interpretation, Amal Mattu, reviews the differential while highlighting the characteristic EKG findings of a can’t-miss diagnosis.

3. Okay, so DKA isn’t exactly a “cardiac” condition – but the worst-case-scenario is still hemodynamic collapse, right? It counts. The EBM gurus over at Anand Swaminathan’s blog EMLyceum give you the latest & greatest when it comes to evidence-based care of DKA.

Oldie But Goodie:

So you’ve achieved the nigh-impossible – achieved sustained ROSC in an OHCA patient. Now what? The reigning American Idol of EM Critical Care, Scott Weingart, tells you what in an excellent two-part interview with one of the lead authors of the TTM trial, Stephen Bernard.

F(FN)OAM:

Worst-case scenario #137: Running ACLS on a patient brought in with PEA arrest. As CPR continues, the staff looks to you. “Uhhhhhh…more Epi?” Like all things resus, you need a systematic approach. The smart dudes over at EM:RAP, along with EM cardiology expert Amal Mattu, review a newly published paper that will help you do just that in the August 2014 edition.

PubMed link to the paper itself here.

(Once again, contact the Social Media Committee if you need helping subscribing to EM:RAP.)

The Gunner Files:

1. Excellent review article from the journal Emergency Medicine Australasia covering that bane of the overnight Deuce shift. No, not vaginal discharge – dental pain.

2. EMLyceum deals in pearls once again when addressing ocular emergencies.

3. Ryan Radecki over at EMLitofNote looks at a very interesting paper just published in JAMA regarding the use of pulse oximetry and dispo of bronchiolitis patients. 

(And as always, be sure to read the original paper for yourself!)

4. My FOAMed man-crush, Rory Spiegel of EMNerd, tackles the C-spine injury algorithm debate.

5. The Aussies over at St. Elmyn’s get you straightened out when dealing with the breathless patient in the ED. Incredibly high-yield for new ‘terns, but useful for docs of all ages.

Now get to FOAMing! 

As always, comments/concerns/criticisms are appreciated!

C. Sam Smith, PGY-3

Emergency Department management of myasthenic crisis

A 23 year old woman with a history of myasthenia gravis presented with several days of worsening generalized weakness, shortness of breath, and difficulty speaking.  She denies infectious symptoms such as fevers, chills, cough, dysuria, vomiting, or diarrhea.  Given her presentation, there is concern for myasthenic crisis.  She has had multiple similar episodes of these symptoms in the past and is currently being treated with prednisone, cyclosporine, and pyridostigmine.  She has needed IVIG and plasma exchange in the past for myasthenia exacerbations.   Her vital signs were within normal limits, but she was in mild distress from shortness of breath. 

Clinical question: 

What should be done in the ED for patients presenting with signs and symptoms of a myasthenia gravis exacerbation?

Literature:

Myasthenia gravis (MG) is an autoimmune disorder characterized by antibodies to post-synaptic acetylcholine receptors which results in fluctuating weakness.  In severe cases where weakness results in respiratory failure or the inability to swallow, the term myasthenic crisis is used.  Facial weakness, diaphragmatic and accessory muscle weakness may mask typical symptoms of respiratory distress.  Myasthenic crisis and impending respiratory failure is heralded by a forced vital capacity (FVC) of less than 1L and negative inspiratory force (NIF) less than 20 cm of water.  Blood gas measurements are poor indicators of impending respiratory failure since hypoxia and hypercarbia are late indicators of respiratory failure.  Common precipitants of myasthenic crises include infection, certain antibiotics, iodinated contrast agents, surgery, and weaning of immunosuppressants.  

Treatment in the emergency department should focus on frequent evaluation (e.g. every 2 hours) of the patient’s respiratory status with serial FVC and NIF and intubating promptly at signs of respiratory failure.  Sitting the patient upright may help temporize the patient’s dyspnea while preparing for intubation.  Even if not intubated, patients presenting with myasthenic crises will need admission to the ICU.  First line therapies include IVIG and plasmapheresis, both of which take several days to reach full clinical effect by removing acetylcholine receptor antibodies from the circulation.  High dose glucocorticoid therapy and other immunosuppresants such as azathioprine and cyclosporine can be initiated but are intended as long-term therapies and do not provide any benefit in the emergent setting.  Anticholinesterase use, such as pyridostigmine, remains controversial because of the risk of coronary artery vasospasm (resulting in MI) and arrhythmia.  A basic infectious workup, including a chest x-ray and urinalysis, should be considered.  

Take home:

Emergency department management of a patient with myasthenic crisis should focus on frequent and repeated assessment of respiratory status (including NIF, FVC) +/- intubation as necessary and disposition to an ICU.  Medical intervention helps over the longer term, but provides little benefit in the emergency department setting.

References:

1) Chaudhuri A and Behan PO.  Myasthenic crisis.  Q J Med 2009; 102:97–107.

2) Jani-Acsadi A and Lisak RP.  Myasthenic crisis: Guidelines for prevention and treatment. J Neurological Sciences 2007; 261:127–133. 

Kindly contributed by Philip Chan, PGY-2.

Rigid Backboard for Spinal Immobilization?

You are working a busy overnight shift when you see EMS bring in a “trauma packaged” patient – a young, healthy-appearing female, on a hard backboard and with a C-collar in place. Per their report, she was the restrained driver of a vehicle struck from behind at a low rate of speed while stopped at a red light. The patient denies LOC, but is endorsing pain in her neck and all the way down her back. She is complaining that the backboard is uncomfortable and making her back pain worse.

Clinical Question: 

What are the indications for prehospital rigid spine immobilization? Could it have been deferred in this patient?

Literature:

Despite the dogmatic and traditional use of rigid backboards for extrication and transport of patients with possible blunt traumatic injury of the spine, it is not an altogether benign intervention. The discomfort associated with bumpy ambulance rides while secured to a rigid board may worsen a patient’s initial presentation to the ED providers such that unnecessary spinal imaging is ordered. Prolonged transport times on rigid boards have been associated with pressure sore formation and respiratory compromise.

The use of rigid spine immobilization by prehospital providers has become based largely on mechanism of injury and concern for possible spinal cord compromise, rather than being based on signs or symptoms of spinal injury itself. This is the opposite of how diagnosis of such injuries is handled once the patient arrives to the ED. As the validation studies of the NEXUS and Canadian C-spine rules have shown, the risk of a C-spine fracture in a patient with normal mental status and without clinical signs or symptoms of spinal cord injury or distracting injury is vanishingly small.

With this in mind, the National Association of EMS Physicians (NAEMSP) and the American College of Surgeons Committee on Trauma published a position paper in the journal Prehospital Emergency Care entitled “Indications for Prehospital Spinal Immobilization.” This paper (and the accompanying resource document) outlines who should and should not be immobilized based on best evidence.

To begin, patients must first be assessed for a mechanism of injury capable of causing spinal cord injury. This is somewhat open to interpretation by EMS providers, and can vary for different patient populations (i.e., a fall from standing would be a very low-risk mechanism for healthy young adult male but much higher risk in an elderly, frail female). The document specifically addresses penetrating wounds, based on evidence published in a paper in the Journal of Trauma in 2010. Basically, if a penetrating wound to the head, neck, or torso does not obviously affect the area of the spine and is not associated with evidence of spinal injury (including focal neurologic deficits), there is no need for rigid immobilization.

If the mechanism is determined to be a risk for spinal cord injury, the EMS provider must then perform a spinal assessment, which is largely derived from the NEXUS and Canadian rules for C-spine imaging. The spinal assessment is “positive” if there is any midline tenderness, palpable/visible midline deformity, or a new neurologic deficit. Immobilization must also be considered for those in which a spinal assessment is unreliable. This includes patients with altered mental status, who are intoxicated with alcohol or drugs, who have a painful distracting injury (by NAESMP criteria, a long bone fracture proximal to the wrists or ankles), or who are otherwise unable to fully participate in the exam due to a language barrier or due to age (i.e., pre-verbal pediatric patients).

If this assessment is negative, NAESMP recommends a C-collar should still be placed if the patient is over 65 (due to increased risk of C-spine injury in this population), but the patient does not require further spinal immobilization and can be transported in position of comfort. Obviously, a C-collar should be placed on any patient if there is midline tenderness in the C-spine.

Interestingly, a study from the Journal of Emergency Medicine published in 2013 reported data from a high-speed infrared motion analysis of healthy volunteers that showed those who extricated themselves with a C-collar in place had less spinal motion than those who were told to hold still while EMS crews attempted extrication themselves. Thus, if the patient is able to extricate themselves and able to ambulate, they should be allowed to do so. If their spinal assessment is positive, they can then be secured to the stretcher with seatbelts, which has been shown to be as effective at immobilizing the T- and L-spine as a rigid backboard. If the patient cannot self-extricate, they can be extricated using standard equipment and transported to the stretcher via a hard backboard. However, he or she should be logrolled off the backboard once reaching the stretcher to minimize time spent on the hard board. The safety of this approach is reinforced by data from other studies which have shown an extremely remote risk of significant (i.e., surgical) T- or L-spine injury in restrained persons in low-risk MVCs.

Take home: 

Remember that securing to the stretcher is an effective mode of spinal immobilization. Rigid backboards should probably be reserved for transfer of a nonambulatory patient from the scene to the stretcher, and should be removed as soon as possible.

References:

1) Prehosp Emerg Care. 2014;18(2):306-14.
2) J Trauma. 2010;68(1):115-20.
3) J Emerg Med. 2013;44(1):122-7.
4) Spine J. 2014. PMID 24486471 [EPub].
5) J Emerg Med. 2006;31(4):403-5.
6) Injury. 2006;36(4):519-25.

Kindly contributed by Sam Smith, PGY-3.