In this episode, I’ll discuss neostigmine plus anticholinergics vs sugammadex and the incidence of postoperative delirium.
When the cholinesterase inhibitor neostigmine is administered to reverse neuromuscular blockade after surgery, an anticholinergic such as glycopyrrolate or atropine must also be given to attenuate the cholinergic side effects from neostigmine. However there is a concern that administration of these anticholinergics may lead to an increased incidence of postoperative delirium. As sugammadex does not require an anticholinergic to be given with it, this presents a possible advantage in decreasing the exposure to a medication that could cause delirium.
To test this hypothesis, a group of authors performed and published in Anesthesia and Analgesia a single-center retrospective cohort study of nearly 50,000 patients who received either sugammadex or neostigmine plus glycopyrrolate or atropine for reversal of neuromuscular blockade. The primary outcome was presence of delirium within the first 4 days after surgery, defined as at least 1 positive brief Confusion Assessment Method (bCAM) screening. A secondary outcome was early delirium within the first 24 hours.
About 14% of the patients in the cohort received sugammadex with 86% receiving neostigmine. To adjust for potential biases between groups, the authors applied propensity weighting and found that the incidence of delirium was 1.09% in the sugammadex group and 0.82% in the neostigmine group. This difference did not reach statistical significance.
As for the secondary outcome, sugammadex was significantly associated with an increased incidence of early postoperative delirium, with an estimated odds ratio of 1.71 and a 95% confidence interval of 1.07-2.72.
The authors concluded:
Compared to neostigmine, use of sugammadex for reversal of neuromuscular block was not associated with an increased risk of postoperative delirium in this retrospective single-center study. Though sugammadex was associated with a statistically significant increased risk of postoperative early delirium, the difference was small and not clinically relevant, and may reflect the presence of unknown confounders.
What stuck out to me right away was how differently I think the abstract for this article would have been written if the findings were exactly reversed. If the Brand Name medication had a lower but non-significant incidence of the primary outcome, I bet it would have been described as “a trend in favor of sugammadex”. Or, if sugammadex had the lower rate of early postoperative delirium, I bet it would have been described as a potentially positive finding that should be confirmed in a randomized trial. Am I too cynical or do you agree? Let me know in the comments.
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