The influence of mild hypothermia on reversal of rocuronium-induced deep neuromuscular block with sugammadex

BACKGROUND Mild hypothermia may be frequently induced due to cool environments in the operating room. The study analyzed patient recovery time and response to sugammadex after a prolonged rocuronium-induced deep neuromuscular block (NMB) during mild hypothermia. METHODS Sixty patients were randomly (1:1) allocated to the mild hypothermia and normothermia groups, defined as having core temperatures between 34.5-35°C and 36.5-37°C, respectively. Patients received 0.6 mg/kg of rocuronium, followed by 7-10 μg/kg/min to maintain a deep NMB [post-tetanic count (PTC) 1-2]. After surgery, the deep NMB was reversed with sugammadex 4.0 mg/kg. The primary end-point was the time until the train-of-four (TOF) ratio was 0.9. RESULTS The appropriate neuromuscular function (TOF ratio ≥ 0.9) was restored after sugammadex was administered, even after hypothermia. The length of recovery in the hypothermia patients [mean (SD), 171.1 (62.1) seconds (s)] was significantly slower compared with the normothermia patients [124.9 (59.2) s] (p = 0.005). There were no adverse effects from sugammadex. CONCLUSIONS Sugammadex safely and securely reversed deep rocuronium-induced NMB during mild hypothermia. An additional 46 s was required for recovery from a deep NMB in hypothermia patients. Based on the results, we think this prolonged recovery time is clinically acceptable. TRIAL REGISTRATION ClinicalTrials.gov Identifier: NCT01965067.