The prolonged duration of rocuronium in Chinese patients

We compared the potency and duration of action of rocuronium in Chinese and Caucasian patients during general anesthesia. Thirty-six women (18 Caucasian and 18 Chinese) and 36 children (18 Caucasian and 18 Chinese) were evaluated during the administration of propofol/fentanyl anesthesia. Patients in each age group were randomized into three subgroups to receive single doses of 0.06, 0. 12, or 0.18 mg/kg rocuronium (adults) or 0.12, 0.18, or 0.24 mg/kg rocuronium (children). Neuromuscular blockade was assessed by electromyography of the adductor pollicis after train-of-four (TOF) stimulation of the ulnar nerve. Dose response curves were constructed when maximum neuromuscular depression of the first twitch of the train (T(1)) was obtained. A second bolus dose of rocuronium was then administered to a total dose of 0.6 mg/kg. The times of spontaneous recovery to T(1) 10%, 25%, and 90% of control and to TOF 0.25, 0.50, and 0.70 were recorded. For both adults and children, recovery occurred later in Chinese than in Caucasian patients (P<0.05 for T(1) of 10%, 25%, 75%, and 90% and TOF to 0.7). The 50% effective dose was smaller in Chinese adults (125+/-63 vs. 159+/-66 microg/kg) and Chinese children (171+/-43 vs. 191+/-46 microg/kg) than in Caucasian adults and children, but the difference was not statistically significant. In adults, time to 25% T(1) recovery was 43+/-13 min in Chinese patients and 33+/-10 min in Caucasian patients (P<0.05). The corresponding values were more rapid for children: 30+/-10 and 24+/-6 min (P<0.05). We conclude that the recovery from rocuronium neuromuscular blockade was longer in Chinese compared with Caucasian patients and in adults compared with children.