The dose of sugammadex recommended by the manufacturer for reversal of rocuronium is 2 mg/kg when the train-of-four count is 2 or more and 4 mg/kg when it is less than 2 but there is a post-tetanic count of at least 1. The purpose of this dose-finding study was to titrate sugammadex to produce a train-of-four ratio ≥0.9 at the conclusion of cardiac surgery, and to continue monitoring neuromuscular blockade in the ICU to identify recurrent paralysis. The hypothesis was that many patients would require less than the recommended dose of sugammadex, but that some would require more, and that recurrent paralysis would not occur.
Neuromuscular blockade was monitored using electromyography during cardiac surgery. Administration of rocuronium was at the discretion of the anesthesia care team. During sternal closure, sugammadex was titrated in 50 mg increments every 5 minutes until a train-of-four ratio ≥0.9 was obtained. Neuromuscular blockade was monitored with electromyography in the ICU until sedation was discontinued prior to extubation or for a maximum of 7 hours.
Ninety-seven patients were evaluated. The dose of sugammadex required to achieve a train-of-four ratio of ≥0.9 varied from 0.43 to 5.6 mg/kg. There was a statistically significant relationship between the depth of neuromuscular blockade and the sugammadex dose required for reversal, but there was a large variation in dose required at any depth of neuromuscular blockade. Eighty-four of 97 patients (87%) required less than the recommended dose, and 13 (13%) required more. Two patients required additional sugammadex administration for recurrent paralysis.
When sugammadex was titrated to effect, the dose was usually less than the recommended dose, but it was more in some patients. Therefore, quantitative twitch monitoring is essential for ascertaining that adequate reversal has taken place following sugammadex administration. Recurrent paralysis was observed in 2 patients.