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Paucis Verbis card: Interpretation of intraosseous blood

IO needles intraosseous labs

There is a growing number of normal volunteers who agree to get an intraosseous (IO) needle placed. Just search Intraosseous Needle on Youtube. Often you can draw blood out of the needle. How do you interpret the lab values? Are they the same as your peripheral blood draw? Should we even send the blood to the lab?

In a 2010 article in Archives of Pathology and Laboratory Medicine, peripheral IV blood from 10 volunteers was compared to blood drawn twice from a single IO line in the humerus. After discarding the first 2 mL of IO blood, the first IO sample was drawn (4 mL). Then a second IO sample was drawn (4 mL), which is equivalent to a sample with the first 6 mL discarded.

Interesting, not all IO labs correlated with IV labs. The good news is that a few critical ones do show correlation: creatitine, glucose, and hematocrit.

PV Card: Interpreting Labs from the IO Line


Adapted from [1]
Go to ALiEM (PV) Cards for more resources.

Thanks to Dr. Michael McGonigal at Trauma Professional’s Blog for posting about this.

Reference

  1. Miller L, Philbeck T, Montez D, Spadaccini C. A new study of intraosseous blood for laboratory analysis. Arch Pathol Lab Med. 2010;134(9):1253-1260. [PubMed]
By |2021-10-11T15:23:29-07:00Jan 13, 2012|ALiEM Cards, Heme-Oncology|
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Paucis Verbis: Serotonin syndrome

Synapses serotonin syndrome

Background

Serotonin syndrome is caused by the excess of serotonin and presents classically as:

  • Altered mental status
  • Autonomic instability
  • Neuromuscular hyperactivity

Fortunately, there’s a nice algorithm (Hunter’s decision rule) which helps you decide whether it is serotonin syndrome or not. I also include a table, which I adapted from a New England Journal of Medicine review article, which helps you to differentiate it from its mimickers, such as anticholinergic syndrome, neuroleptic malignant syndrome, and malignant hyperthermia.

PV Card: Serotonin Syndrome


Adapted from [1, 2]
Go to ALiEM (PV) Cards for more resources.

A video to remind you what clonus looks like:

Thanks to Dr. Steve MacDade (Univ of Florida, Jacksonville EM resident) for the idea!

References

  1. Boyer E, Shannon M. The serotonin syndrome. N Engl J Med. 2005;352(11):1112-1120. [PubMed]
  2. Ables A, Nagubilli R. Prevention, recognition, and management of serotonin syndrome. Am Fam Physician. 2010;81(9):1139-1142. [PubMed]
By |2021-10-11T15:32:25-07:00Jan 6, 2012|ALiEM Cards, Tox & Medications|
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Paucis Verbis: Acute vestibular syndrome and HINTS exam

Dizziness HINTS exam acute vestibular examWhat is your diagnostic approach to the acutely vertiginous patient?

The bottom-line question is: Is the cause peripheral or central in etiology?

In this great 2011 systematic review article in CMAJ on Acute Vestibular Syndrome (AVS), the authors review how (un)predictive elements of the history and physical exam are. By definition of AVS, symptoms must be continuous for at least 24 hours and have no focal neurologic deficits.

Frighteningly, the authors report many of the signs and symptoms (type of dizziness, hearing loss, patterns of nystagmus, Hallpike-Dix) are not as predictive as we classically are taught!

The take home point is to learn and incorporate the 3-part HINTS exam into your diagnostic approach (see bottom box on card). It is reported to be as good as a diffusion-weighted MRI for diagnosing a posterior stroke. The steps are:

  1. Do the horizontal head impulse test. (Normal = central cause)
  2. Check for directionally-alternating nystagmus movement on left and right gaze.
  3. Do the alternate cover test.

PV Card: Acute Vestibular Syndrome vs Stroke | The HINTS Exam


Adapted from [1]
Go to ALiEM Cards for more resources.

There is a helpful 10-minute video showing normal and abnormal HINT findings:

  • Head impulse testing
  • Nystagmus testing
  • Testing of skew

VIDEO LINK: http://emcrit.org/misc/posterior-stroke-video/

Thanks to Dr. Brian Resler (UCSF-SFGH EM resident) for giving me the heads up about this at Followup Conference!

Reference

  1. Tarnutzer A, Berkowitz A, Robinson K, Hsieh Y, Newman-Toker D. Does my dizzy patient have a stroke? A systematic review of bedside diagnosis in acute vestibular syndrome. CMAJ. 2011;183(9):E571-92. [PubMed]
By |2026-06-16T16:02:58-07:00Dec 2, 2011|ALiEM Cards, Neurology|
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Paucis Verbis: aVR Lead on ECG

ECG leads aVR lead

What lead is the most overlooked on the ECG?

 Answer: aVR Lead

This lead can provide some unique insight into 5 different conditions:

  1. Acute MI
  2. Pericarditis
  3. Tricyclic antidepressant (TCA) and TCA-like overdose
  4. AVRT in narrow complex tachycardias
  5. Differentiating VT from SVT with aberrancy in wide complex tachycardias by using the Vereckei criteria (possibly better than Brugada criteria)

PV Card: The aVR Lead on ECG


Adapted from [1-4]
Go to ALiEM (PV) Cards for more resources.

See also:

References

  1. Williamson K, Mattu A, Plautz C, Binder A, Brady W. Electrocardiographic applications of lead aVR. Am J Emerg Med. 2006;24(7):864-874. [PubMed]
  2. Vereckei A, Duray G, Szénási G, Altemose G, Miller J. New algorithm using only lead aVR for differential diagnosis of wide QRS complex tachycardia. Heart Rhythm. 2008;5(1):89-98. [PubMed]
  3. Kireyev D, Arkhipov M, Zador S, Paris J, Boden W. Clinical utility of aVR-The neglected electrocardiographic lead. Ann Noninvasive Electrocardiol. 2010;15(2):175-180. [PubMed]
  4. Riera A, Ferreira C, Ferreira F, et al. Clinical value of lead aVR. Ann Noninvasive Electrocardiol. 2011;16(3):295-302. [PubMed]
By |2021-10-11T15:47:33-07:00Nov 18, 2011|ALiEM Cards, Cardiovascular, ECG|
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