To the Editor:
We read with interest the article by Drzymalski et al.1 published in a recent issue of Anesthesiology. The authors assessed the effect of a cognitive aid on reducing the use of sugammadex and its associated costs using an interrupted time series analysis.1
We are fortunate to work in a department that provides quantitative neuromuscular blockade monitoring in every anesthesia workstation. In fact, we have been faced with cases of prolonged neuromuscular blockade and reversal with rocuronium and sugammadex that would have been overlooked without monitoring.2 We prize the use of quantitative monitoring as the body of evidence that demonstrates the importance of train-of-four ratio of 0.9 or greater has long been present.3 Furthermore, recent evidence is building towards an adequate level of reversal with a train-of-four ratio of 0.95 or greater.4
We appreciate the value of these measures in a setting where only qualitative neuromuscular blockade monitoring is available and applaud the authors for accomplishing their main objective. The authors state that new peripheral nerve stimulators were purchased and placed in every anesthetizing locations.1 We would like to understand why quantitative monitors were not selected for acquisition if you had a budget and operational peripheral nerve stimulators were available in every station before the month of intervention. Our concern is that the reduction in use of sugammadex, derived from the intervention, was aided by better monitoring equipment, not previously available. In fact, the authors found that the decrease in costs was due to a decreased use of sugammadex but also from neuromuscular blocking drugs and reversal agents.1 Could this finding be due to an increase in monitoring or simply because fewer general anesthetics with neuromuscular blockade were performed? According to the authors’ cognitive aid, every patient should receive a reversal agent (from 4 mg/kg sugammadex with 0 to 1 twitches to 20 mcg/kg neostigmine with 4 twitches without fade).1 The article does not present the number of neostigmine administrations pre- or postcognitive aid, but one should expect an increase in use and costs postintervention. Regarding sugammadex administrations, the article states that the postintervention monthly rate of sugammadex administration was 4 per 1,000 general anesthetics with a nonsignificant P.1 We do not understand the meaning of this statement as that information contradicts the information presented in the figures. Concerning the adverse respiratory events, the authors cautiously state that significant changes were not observed.1 Although that can be a statistically sound statement, the regression of the interrupted time series analysis seems to be less fitted when evaluating the adverse respiratory events. One can notice that the highest value of adverse respiratory events was, in fact, recorded in the postintervention period.
Despite all of our considerations, we find the published article of very high quality. We congratulate the authors for accomplishing their goals, reducing costs without having a negative impact on patients’ outcomes, and urge the use of such measures in places where qualitative measurement of neuromuscular blockade is not available.
Dr. Esteves has received lecture and consultant fees from Merck Sharp & Dohme Portugal (Lisboa, Portugal). The other authors declare no competing interests.