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.