Quiz 167, November 11, 2022

Welcome to the 167th FOAMed Quiz.


Question 1

Source image: www.radiopaedia.org

Acute decompensated heart failure is the cause of dyspnea in up to 40% of the older adults in the ED. Accurate and timely diagnosis is important.

When comparing POCUS to plain radiography, which has the highest sensitivity for acute decompensated heart failure?

A: Plain radiography


C: The sensitivity of plain radiography and ultrasound is equal

The correct answer is B

POCUS versus plain radiography for acute decompensated heart failure was covered on CanadiEM last week.

The sensitivity of POCUS for acute decompensated heart failure is about 90 percent, compared to a sensitivity of about 70 percent of plain radiography. The specificity of both modalities is more or less equal.

Clinical Question: How does the sensitivity/specificity of lung ultrasound compare to plain films in diagnosing acute decompensated heart failure?

Question 2

Source image: www.mountsinai.org

Manual pulse checks during CPR tend to be quite inaccurate.

In this recently published paper, 54 patients and 213 pulse checks were analysed during CPR. All patients had an arterial line in place. During a pulse check, manual pulse detection, femoral artery doppler ultrasound clips, and systolic blood pressure were recorded simultaneously.

The primary outcome was detection of any pulse which correlated with an arterial line signal.

What did the authors find?

A: Manual pulse check was more accurate than doppler ultrasound

B: Doppler ultrasound was more accurate than manual pulse check

C: Manual pulse check and doppler ultrasound were equally accurate

The correct answer is B

Taming the SRU covered the paper last week.

The accuracy of doppler ultrasound of the femoral artery was higher than manual palpation (95.3% vs. 54.0%; p < 0.001) for detection of any pulse during the pulse checks.

Question 3

Source image: www.nejm.org

Which of the following recommendations concerning irrigation in laceration wound care is supported by evidence?

A: Irrigation leads to fewer wound infections

B: High pressure irrigation leads to fewer wound infections

C: 50 to 100 mL of irrigation for every centimetre of the laceration leads to fewer wound infections

D: Irrigation with povidone-iodine leads to delayed wound healing

E: Irrigation with normal saline leads to fewer wound infections compared to tap water

F: None of the recommendations above are supported by evidence

The correct answer is F

Justin Morgenstern covered the literature behind irrigation of lacerations on First10EM last week.

Apparently there is not a lot of data on this subject and the available data isn’t very conclusive.However, that doesn’t mean you should change your practice.

How should we irrigate lacerations? Does it even matter?

Question 4

Source image: http://hqmeded-ecg.blogspot.com/

Your patient’s ECG shows bizarre T-waves and you suspect a ‘’pulse tapping artefact’’.

What causes a pulse tapping artefact?

A: The patient taps his of her finger on an electrode, synchronous to the heartbeat

B: An electrode is placed on top of an artery

C: The ECG lead junction box is connected in a wrong way

D: The patient has a Parkinsonian tremor

The correct answer is B

A case of pulse tapping artefact was covered on dr. Smiths ECG blog.

A pulse tapping artefact or arterial pulse tapping artefact can be found when an electrode is placed on top of an artery. It is generated by the movement of the electrode with each pulsatile motion of blood flow.

Question 5

The role of dual sequential defibrillation (using 2 defibrillators more or less simultaneously) in refractory shockable rhythms remains uncertain.

In the recently published DOSE VF study, 450 adult patients with out-of-hospital cardiac arrest and refractory ventricular fibrillation (at least 3 attempts at defibrillation had been unsuccessful) were randomised to either:

– Standard defibrillation

– Vector Change defibrillation: pads were changed to an anterior-posterior position

– Double Sequential defibrillation

Source image: www.nejm.org

The primary outcome was survival to hospital discharge.

What did the authors find?

A: Patients in the Double Sequential defibrillation group and patients in the Vector Change defibrillation group had a statistically significant higher survival to hospital discharge rate compared to standard defibrillation

B: Patients in the Double Sequential defibrillation group had a statistically significant higher survival to hospital discharge rate compared to standard defibrillation. Patients in the Vector Change defibrillation group did not

C: Survival to hospital discharge was not statistically significantly different between the 3 groups

The correct answer is A

The paper was covered on First10EM and UMEM last week.

Both treatment groups were statistically superior to standard defibrillation. Survival was 30.4% with Double Sequential defibrillation, 21.7% with Vector Change defibrillation, and 13.3% with standard care.

However, keep in mind this trial is unblinded and stopped early without a pre-specified endpoint. Justin Morgenstern sums up the methodological issues nicely on First10EM.

One other issue to consider is the possibility of damaging a defibrillator by using Dual Sequential defibrillation.

Dose VF: A double sequential defibrillation game changer?

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This quiz was written by Sophie Nieuwendijk, Denise van Vossen, Gijs de Zeeuw, Nicole van Groningen, Jeroen van Brakel, Noortje Geerts and Renée Deckers

Reviewed and edited by Rick Thissen