Acute tolerance to rocuronium -A case report.

Background: A booster dose can result in a similar reaction to the initial dose. Neuromuscular blocking agents (NMBAs) can produce a comparable reaction in the absence of specific pathophysiologic alterations.

Case: An initial dose of rocuronium 40 mg was given to a male patient (50 years old, height 168 cm, weight 54 kg, body mass index 19.13 kg/m2) for anesthesia. The onset was usual, but the duration was brief. Two booster doses were administered at 20 min intervals, but recovery came quickly. So, acute tolerance was suspected. Muscle function was restored to greater than train-of-four ratio 0.75 while spontaneous aided breathing was maintained without the need of further NMBAs. Following the operation, sugammadex (1.85 mg/kg) was provided to prevent residual neuromuscular inhibition.

Conclusions: Anesthetists must be able to suspect acute tolerance to NMBAs in patients with no unique medical history and have a plan to resolve it.