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Letter to the Editor

Much Ado about Nothing

doi: 10.1097/01.EEM.0000574856.00862.46
Letter to the Editor

Editor:

Richard Pescatore, DO, recently penned an article decrying the use of bilevel positive airway pressure in pulmonary edema. (“The Dumbing Down of Respiratory Support,” EMN 2019;41[6]:1; http://bit.ly/31qIQAG.)

I agree with him that an intervention that offers no benefit may offer harm. Citing forest plots from a meta-analysis from 2013 (Am J Emerg Med. 2013;31[9]:1322), he stated that there is “an undeniable pattern of CPAP outperforming BiPAP.” He ignored the fact that not one showed statistical difference, and the point estimates of effect (or harm) themselves were little removed from unity.

It appears the promotion of CPAP over BiPAP is primarily due to stylistic reasons. I agree that mechanistically BiPAP likely offers nothing over CPAP and BiPAP is more complex, but I cannot agree with what Dr. Pescatore wrote, that “IPAP/EPAP oscillations adds complexity without benefit amid recurrent signals of harm.”

The data, when reviewed dispassionately, do not support this conclusion. The harm reported in these studies is increased incidence of myocardial infarction in the BiPAP group. This stems from nonsignificant findings in a 27-patient randomized, controlled trial (Crit Care Med. 1997;25[4]:620) and a meta-analysis (Lancet. 2006;367[9517]:1155), hardly a compelling signal, especially when the largest RCT to date of more than 1000 patients showed no such signal. (N Engl J Med. 2008;359[2]:142.)

A subsequent small RCT (J Emerg Med. 2014;46[1]:130) and a massive registry study (Eur J Intern Med. 2018;53:45) have shown no discernable differences in CPAP and BiPAP in pulmonary edema with respect to benefit or harm. In short, this article is much ado about nothing because when large RCTs and registry trials show no difference, maybe there isn't one?

Michael A. Jasumback, MD

Great Falls, MT

Dr. Pescatore responds: Thank you for your letter. I've already laid out my reasoning in the original article, so I'd like to tell a story to make my point. When I was first learning how to use tools to fix things, I asked my father why I'd ever buy a wrench set—couldn't a monkey wrench meet all my needs? My dad chuckled, knowing that soon enough I'd learn the lesson that everyone learns eventually: When the task matters, using the right tool for the right job gets it done faster, cleaner, and better.

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