The recently published article "Instant Feedback" (December JEMS) gives an excellent overview of point-of-care (POC) testing available in the field. Case #1 describes the patient as having a slow, wide, regular rhythm with a rate of 60, interpreted as V-tach. The article adds that if the decision to treat had included defibrillation or cardioversion, the patient would likely have ended up with intractable asystole. I agree that the potentially incorrect treatment might have produced a fatal outcome, but I wonder what sort of advanced provider could be that far off the mark in both diagnosis and care.
Assuming the provider didn’t have enough information to recognize the sine wave pattern or potential for hyperkalemia, interpreting a slow and wide rhythm as a V-tach indicates a lack of basic rhythm interpretation. Tachycardia is an abnormally rapid heartbeat, generally above 100 bpm in the normal adult. At best, a misdiagnosis might include an accelerated idioventricular rhythm (AIVR). Additionally, cardioversion is indicated for an unstable tachycardia; this case involves a borderline bradycardic rhythm. Although rates of 60 rarely require immediate intervention, it would seem that pacing would be a better choice than cardioversion if the provider actually believed that to be the cause of the hypotension.
I commend the authors for their coverage of relatively recent advances in field diagnostics, and I believe that POC testing would enhance the treatment of this patient, but the consideration of cardioversion for a patient with a slow rhythm represents a deviation from expected standards of care.
Lew Steinberg, MPA, NREMT-P
Palm Beach Gardens, Florida
"Instant Feedback" authors Deems Okamoto, MD, and Paul A. Berlin respond: Thanks for the feedback on our POC article. The comments regarding Case #1 in "Instant Feedback" are both appreciated and cogent. The case study was actually designed with the intent of describing a slow, wide-based rhythm with a rate less than 100 bpm and more than 40 bpm to promote just such a discussion.
This case study has been used in our ACLS for Experienced Provider courses for the past 12 years as an example of hyperkalemia due to a potassium over 10 meq/L. On presenting the initial scenario and showing an accompanying sine wave, the first question to the participants asks for a rhythm diagnosis. Without exposing the diagnosis, the next question asks for a plan of treatment according to the patient’s described condition.
Invariably, the rhythm is most commonly interpreted as "ventricular tachycardia, too slow to be ventricular tachycardia, a bradycardia, an idioventricular rhythm, hyperkalemia or unknown sinus rhythm." Each individual is then queried for their treatment modality prior to exposing the clinical diagnosis and discussing the preferred treatment regimen. Presenting the case study in this fashion has given us the opportunity to quickly gauge the expertise of the participants in interpreting the rhythm and diagnosing its malignant cause.
Unfortunately, the constraints of the published article did not give us an opportunity to expand on this educational technique, so the single most disastrous example of a rhythm misinterpretation and subsequent intervention was chosen to emphasize the utility of a POC potassium in clarifying the diagnosis.
In the March issue, the cover photo was incorrectly attributed to Chris Swabb. It was actually shot by Ray Kemp. We regret the error. JEMS