Paucis Verbis: Blunt Abdominal Injury, Likelihood Ratios

This month’s issue of JAMA addresses the question “Does this patient have a blunt intra-abdominal injury?” as part of the always-popular Rational Clinical Examination series.

The systematic review of the literature summarizes the accuracy of findings for your blunt trauma patient in diagnosing intra-abdominal injuries. Specifically, likelihood ratios (LR) are summarized. These LRs can be used to plot on the Bayes nomogram below. You draw a straight line connecting your pretest probability and the LR. This yields your posttest probability.

The most predictive positive LR include: Abdominal rebound tenderness, a “seat belt sign”, ED hypotension, hematocrit < 30%, AST or ALT > 130, urine with > 25 RBCs, base deficit < -6 mEq/L, and a positive FAST ultrasound.

The trouble is that the absence of these findings aren’t as helpful in ruling-out injury, with negative LR’s very close to 1.0. The two exceptions are base deficit and FAST ultrasound with a negative LR of 0.12 and 0.26, respectively.

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

I find it interesting that there are studies on hepatic transaminase levels. Anyone else getting these in their trauma patients? I traditionally don’t. Many of our patients have a history of hepatitis C and underlying alcoholic hepatitis. If suspicious for blunt abdominal trauma, we just get the CT.

Reference

Nishijima D, Simel D, Wisner D, Holmes J. Does this adult patient have a blunt intra-abdominal injury? JAMA. 2012;307(14):1517-1527. [PubMed]

By Michelle Lin, MD|2021-10-10T19:02:16-07:00Apr 20, 2012|ALiEM Cards, Gastrointestinal, Trauma|

Trick of the Trade: Peritonsillar abscess aspiration technique using IV tubing

A few weeks ago, I gave a Tricks of the Trade talk for the Stanford-Kaiser Emergency Medicine residents and faculty. I was overwhelmed by the great, creative ideas that came up during our discussion. An always popular topic is the drainage of peritonsillar abscesses. Sometimes it can be difficult to aspirate from a syringe using only one hand, especially with the awkward angle that you might encounter.

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By Michelle Lin, MD|2024-10-22T15:42:12-07:00Apr 17, 2012|ENT, Tricks of the Trade|

Paucis Verbis: GRACE score for ACS risk stratification

Risk stratification of the undifferentiated chest pain patients in the Emergency Department continues to plague emergency physicians. It’s partly the reason why I created a TIMI risk score card for unstable angina and non-ST elevation MI in 2010.
Have you heard of the 9-variable GRACE risk stratification score? Thanks to Jeff Bray (physician assistant in a rural critical access ED), I have now. He graciously shared his personal reference card on this with me, which I only minimally reformatted to fit my Paucis Verbis card dimensions.

GRACE stands for Global Registry for Acute Coronary Events. It supposedly outperforms the TIMI scoring slightly in accurately predicting complications in the short and long term. Instead of calculating this manually, which can be a pain, now there are calculators out there:

Anyone use this scoring system?

PV Card: GRACE Risk Score for ACS

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

References

Eagle K, Lim M, Dabbous O, et al. A validated prediction model for all forms of acute coronary syndrome: estimating the risk of 6-month postdischarge death in an international registry. JAMA. 2004;291(22):2727-2733. [PubMed]
D’Ascenzo F, Biondi-Zoccai G, Moretti C, et al. TIMI, GRACE and alternative risk scores in Acute Coronary Syndromes: a meta-analysis of 40 derivation studies on 216,552 patients and of 42 validation studies on 31,625 patients. Contemp Clin Trials. 2012;33(3):507-514. [PubMed]

By Michelle Lin, MD|2021-10-10T19:05:05-07:00Apr 13, 2012|ALiEM Cards, Cardiovascular|

Trick of the Trade: Urine pregnancy test without urine

A 25 year old woman presents to the Emergency Department having syncopized in the waiting room, where she was triaged with the chief complaint of abdominal pain. Ectopic pregnancy immediately bubbles to the top of your differential diagnosis. The patient is too dizzy to walk to the bathroom to give you a urine specimen to check a urine pregnancy test. Plus, she admits that she just urinated in the waiting room bathroom a few minutes ago – so no urine now.

Trick of the Trade

Apply several drops of whole blood (instead of urine) into the pregnancy test cassette. In the photo below, the patient was pregnant with a serum beta-HCG level of 250 mIU/mL whose urine and whole blood qualitative tests were both positive.

Did you know that most urine pregnancy test kits are approved for both urine and serum samples? On a quick Google search, I found that Accutest, Cardinal Health, ICON, OSOM, and Rapid Response all are approved for both. The question is whether this will work for whole blood.

One study ¹ in the Journal of Emergency Medicine by Dr. Fromm from Maimonides Medical Center looked at exactly this issue. Whole blood pregnancy test performed extremely well, especially if positive:

Sensitivity 95.8%
Specificity 100%
Negative predictive value 97.9%
Positive predictive value 100%

In their study, very low beta-HCG values (<159 mIU/mL) occasionally yielded a false negative for whole blood pregnancy tests. The whole blood testing approach missed a total 9 of 425 pregnancies. Interestingly, the urine pregnancy test was also negative in 5 of those 9 and not performed in the other 4.

Bottom Line

Believe a positive test. Confirm all tests with a urine qualitative test or quantitative serum beta-HCG.

Tip

Be sure to wait at least 5 minutes when using whole blood in the kit. It sometimes takes a while.
Do not apply additional drops of water or saline to the whole blood sample. This causes unnecessary dilution. Just wait for the blood to osmose across the entire test strip.
This is trick is ONLY for medical professionals and not the lay public. We are discussing an actual blood draw and not a simple cut on a finger to obtain blood.

Another example courtesy of Dr. Joe Habboushe (New York Hospital–Queens of Cornell University) and Dr. Graham Walker (Stanford) ² :

S = Sample well; T = Test specific (will show bar if +HCG); C = Control (will always have a bar)

References

Fromm C, Likourezos A, Haines L, Khan A, Williams J, Berezow J. Substituting whole blood for urine in a bedside pregnancy test. J Emerg Med. 2012;43(3):478-482. [PubMed]
Habboushe J, Walker G. Novel use of a urine pregnancy test using whole blood. Am J Emerg Med. 2011;29(7):840.e3-4. [PubMed]

By Michelle Lin, MD|2020-12-04T13:15:41-08:00Apr 10, 2012|Expert Peer Reviewed (Clinical), Ob/Gyn, Tricks of the Trade|

Modern EM: Case #4 – Palpitations

Case # 4: Palpitations

A 25 year old woman presents with palpitations, sweating, and shortness of breath since this morning. 6 days ago she had syncopized, was shocked out of V-tach by EMS, and eventually had a defibrillator placed for an unknown arrhythmia. Now, she feels her heart beating in her chest, looks diaphoretic, is tachypnic, but her pulse is 58 and regular.

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By Timothy Peck, MD|2016-11-18T10:03:19-08:00Apr 9, 2012|Cardiovascular, Social Media & Tech|

Trick of the Trade: Fluorescein eyedrops

This is a guest post by Dr. Ian Brown (Stanford):

The Roberts textbook describes the procedure of corneal fluorescein staining as touching a moistened fluorescein strip to the cornea. Maybe it is an irrational fear of a paper cut to the sclera, or a fear of touching an already abraded cornea with the paper, but I try to find an alternative. I have seen physicians hold the eye open with one hand, hold the fluorescein with a second hand and then drip tetracaine on the paper and let it drip into the eye with a third hand. I, unfortunately, only have two hands.
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By Michelle Lin, MD|2019-01-28T23:36:28-08:00Mar 27, 2012|Ophthalmology, Tricks of the Trade|

Modern EM: Case 1 and 2 – Strep Throat

A sister and brother, aged 7 and 14, respectively present with pharyngitis. The 7F has sore throat, cough, fever, and post-tussive vomiting for 1 day. She has posterior pharyngeal erythema, no lymphadenopathy, no exudate, no petechiae, and looks like a viral URI.

The 14M had culture confirmed GAS pharyngitis 3 weeks ago, was treated with PCN-VK and symptoms resolved. Now, he’s in the ED with signs and symptoms of pharyngitis again, including dysphagia, fever, cough, posterior pharyngeal erythema, swollen tonsils, LAD, and petechiae on his hard palate.

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By Timothy Peck, MD|2017-03-05T14:18:48-08:00Mar 26, 2012|ENT, Social Media & Tech|