Tiny Tip: Banning Factor Xa – How to remember NOACs

There has been an increase in novel oral anticoagulants (NOACs), which often thought of by many as the non-warfarin anticoagulants. Within this group there are two subclasses:

  • Factor IIa (thrombin) inhibitors
  • Factor Xa inhibitors

One of our @MacEmerg PGY3 residents, Laura Morrison (no relation to esteemed resuscitation Canadian researcher Laurie Morrison) recently told me about a quick and dirty tip to remember what class each of the NOACs belongs to… and thereby helping you to remember its mechanism of action (MOA).

One of these things is not like the other….

Here is the tip:

Look for the suffix -xaban in the Xa inhibitors in the GENERIC name of the med.

For example:

ApiXaban <– Xa inhibitor

RivaroXaban <– Xa inhibitor

Dabiagatran <– NO “Xa” therefore not a Xa inhibitor. (Direct thrombin inhibitor) does not, therefore, fit within this model!!

Laura says you can think of it as “banning” the Xa factor to the abyss…

Laura's Tiny Tip

(NB: This does not work for the trade name…)

Tiny Tips | SVNCOPE for Syncope

Syncope is common presenting complaint in the emergency department. Over 40% of adults will experience a syncopal episode, and syncope accounts for approximately 1% of all ED visits (1).

Because syncope can result from a variety of etiologies, both life-threatening and benign, the syncopal patient is diagnostically challenging and can be especially daunting for learners. A consistent framework helps learners avoid missing a potentially serious underlying problem. The SVNCOPE mnemonic is a useful reminder of the most common causes of syncope. Prevalence of each noted in brackets (2).

  • Situational (5%)
    • Syncope associated with a triggering event, often occurring post-micturition, post-tussive, or with GI stimulation or defecation. A thorough history of the event will yield information about situational causes.
  • Vasovagal (a.k.a. neurocardiogenic; 18%)
    • A transient stimulation of parasympathetic activity resulting in hypotension. This is generally triggered by noxious stimuli, stress, fear, or heat. Has a typical prodrome of lightheadedness, dizziness, diaphoresis, and blurred vision.
  • Neurogenic (10%)
    • Cerebrovascular events such as TIA/stroke, or a subclavian steal syndrome can cause syncope. Generally associated with abnormal neurological examination.
  • Cardiogenic (18%)
    • This type can result from structural pathology (such as aortic stenosis, cardiomyopathy, tamponade, acute MI) or from arrhythmias. Cardiogenic syncope is generally unprovoked and is more common in older patients.
  • Orthostatic (8%)
    • Sudden decrease in blood pressure on standing. Often described by the 30/20/10 rule – after standing for 2 minutes, an increase in heart rate of 30 beats per minute, decrease in systolic blood pressure by 20 mmHg, or decrease diastolic blood pressure by 10 mmHg.
  • Psychogenic (2%)
    • May occur in patients with panic disorders, somatization disorders, and anxiety. Can be difficult to identify, as examination and investigations are often unremarkable. This is a diagnosis of exclusion.
  • Endocrine
    • Always consider hypoglycemia as a possible cause.

It is important to keep in mind that approximately 34% of syncope cases have no identifiable etiology(1). The mnemonic is useful to avoid forgetting possible etiologies of syncope, but will not necessarily lead to a definitive diagnosis.

For a more in-depth review of syncope, head over to LITFL(3) or check out the EM Basic podcast(4) and associated show notes(5).

References

  1. Moya A, Sutton R, Ammirati F, et al. Guidelines for the diagnosis and management of syncope (version 2009). Eur Heart J. 2009;30(21):2631-71.
  2. Gauer RL. Evaluation of syncope. Am Fam Physician. 2011;84(6):640-50.
  3. Syncope. Life In the Fast Lane Blog. Accessed June 10, 2015. Available at: http://lifeinthefastlane.com/ccc/syncope/
  4. Syncope. EM Basic. Accessed June 10, 2015. Available at:  http://embasic.org/syncope/
  5. Syncope Show Notes. EM Basic. Accessed June 10, 2015.  Available at: http://embasic.org/wp-content/uploads/2012/01/13-syncope-show-notes1.pdf

 

Reviewing with the Staff | @TChanMD

Dr. Chan is an assistant professor at McMaster University.  She is also one of our editors here at BoringEM.org.

An approach to syncope is a key concept that any emergency medicine learner should have in his/her back pocket.  That being said, sometimes on history it might not be remarkably clear as to whether the incident was truly a syncopal event or if it might have been due to other causes (e.g. seizure, trauma, narcolepsy, etc..).  It is, therefore, important to broaden your clinical assessment to consider other causes of sudden loss of consciousness that may not classically be considered within the “syncope” differential.

A careful collateral history from bystanders or first responders may be key in revealing differences in etiology, so make sure you hop on the phone and try to see if someone else can give you information about the circumstances of the loss of consciousness.

Tiny Tip: HINTS exam to determine INFARCT

I recently wrote a post about the utility of the HINTS exam for patients who present with persistent vertigo known as acute vestibular syndrome (AVS). The available evidence suggests that this bedside exam is highly effective to help differentiate peripheral from central causes. And in one study, it may even be better than an MRI in the first 48hrs [1]! Finally, the answer to all of your vertiginous problems in the emergency department…except one.

How will you remember how to interpret each component of the HINTS exam?

Have no fear because there is a sweet mnemonic that has been developed. And the beauty of this one is that it actually relates to what you’re trying to remember! Nothing worse than not being able to remember the word that comprises the mnemonic!

Since the most common cause of central vertigo is infarct, it only makes sense that we use INFARCT to remember HINTS . So here goes…

INFARCT = Impulse Normal, Fast-phase Alternating or Refixation on Cover-Test [2].

What does this mean?

Let’s break it down. Recall we apply the HINTS exam to determine if a patient is suffering from a central cause of vertigo (refer to Boring Questions post for a more detailed overview). HINTS is comprised of 3 components:

  1. Head impulse test
  2. Nystagmus
  3. Test of skew

So consider INFARCT (or another central cause) if any of the following:

  1. head Impulse is Normal (no eye saccade with passive head turning)
  2. Fast-phase Alternating (or bidirectional) nystagmus
  3. The eye moves to Refixate during the Cover-Test

That’s it. Use HINTS to evaluate your next patient with persistent vertigo to determine if they have an INFARCT.

References

  1. Kattah, J. C., Talkad, A. V., Wang, D. Z., Hsieh, Y. H., & Newman-Toker, D. E. (2009). HINTS to diagnose stroke in the acute vestibular syndrome three-step bedside oculomotor examination more sensitive than early MRI diffusion-weighted imaging. Stroke40(11), 3504-3510. DOI:10.1161/​STROKEAHA.109.551234
  1. Newman-Toker D. Acute Vestibulary Syndrome (n.d.) Retrieved at: http://content.lib.utah.edu/utils/getfile/collection/ehsl-dent/id/7/filename/5.pdf

 

Tiny Tip | Canadian C-spine Rule Mnemonic

Clinical Decision Tool uptake

In 2007, Dr. Ian Stiell wrote a paper [1] about the uptake and real-life implementation of his four clinical decision rules (or as we prefer to call them, clinical decision tools).  The paper concludes that “Future research should identify implementation barriers and explore strategies to achieve better knowledge uptake in the ED”.

The BoringEM team hypothesizes that the ease of use may be greatly affected by the complexity of a rule itself – i.e. if the tool itself is complex and unwieldy, it may not be readily taken up.  For many people, this has lead to barriers for adoption of the Canadian C-Spine Rules.  Especially when compared to the simpler NEXUS spine rule, this CDR often has been noted by various people to be difficult to actually navigate.  Even though, NEXUS has been shown to be less sensitive than the CCR.

A new mnemonic

To alleviate this, we have previously presented a diagram to help with this, but recently a group of McMaster University medical students came up with a nifty new mnemonic to help remember each of the parts of C-spine rule.  With some editorial support by myself, we’ve added it to the diagram from our previous post for clarity.

Canadian C-spine rule mnemonic

By: Sean Robinson, Yuetming Lam, Steffen de Kok

HIGH RISK FEATURES:
Sixty Five, Fast Drive, Sense Deprive?  Image, if alive.
LOW RISK FEATURES:
Slow Wreck, Slow Neck, Sitting down, Walking ’round, C-Spine fine?  Range the spine!
And ultimately….
If you can look both ways, you can cross the road —-> Without Imaging
CCR Mnemonic
Reference:

Stiell, I. G., & Bennett, C. (2007). Implementation of clinical decision rules in the emergency department. Academic Emergency Medicine, 14(11), 955-959.

Tiny Tip: Determining capacity in an emergency – The CURVES Mnemonic

Determining capacity in a patient that needs to make an emergency medical decision can be a huge challenge for emergency physicians with substantial legal and patient-oriented consequences. As emergency medicine providers we need to be able to make this determination confidently and decisively. By preparing our approach in advance we can be more confident in our decisions.

In November 2014, EM:RAP (check it out!) had a great segment on decision making capacity and covered the article:

Chow, G. V., Czarny, M. J., Hughes, M. T., & Carrese, J. A. (2010). CURVES: a mnemonic for determining medical decision-making capacity and providing emergency treatment in the acute setting. CHEST Journal, 137(2), 421-427.

It provides a concise, applicable approach using the CURVES mnemonic

C – Choose and Communicate – Can the patient make and communicate a choice without coercion?
U – Understand – Does the patient understand the risks, benefits, alternatives, and consequences of their decision?
R – Reason – Is the patient able to reason and provide logical explanations for their decision?
V – Values – Is the decision consistent with the patient’s values?
E – Emergency – Is there a serious or imminent risk to the patient’s well-being?
S – Surrogate – Is there a surrogate decision maker available?

The first four letters (CURV) assess whether or not the patient has decision-making capacity. A patient can be considered to have capacity in a given situation if they can communicate their decision, demonstrate their understanding of their situation, and show that they have a reasonable thought process that is consistent with their values. The final two letters (ES) determine whether treatment can proceed with implied consent in a patient lacking capacity. Treating with implied consent is only appropriate when the patient does not have capacity to make the decision (CURV), it is an emergency, AND there is no surrogate decision maker available.

Notably, the articles stresses that capacity is not an all-or-none phenomenon and can change both over time and depending on the decision under consideration. For example, an inebriated trauma patient may have capacity to decide to accept or decline pain medication but not have the capacity to consent or reject a life-saving surgical intervention.

What do you think of the CURVES mnemonic? As outlined in the referenced article, there are many other ways to assess consent – how do you assess capacity in your emergency department?

Peer reviewed by Teresa Chan (@TChanMD)