Effects of dexmedetomidine on the onset and duration of action in non-depolarizing neuromuscular relaxant rocuronium

Abstract

To determine the impact of two varying doses of dexmedetomidine (DEX) on the onset and duration of neuromuscular blockade of rocuronium (ROC) under the condition of sevoflurane anesthesia. Eighty-one patients, American Society of Anesthesiologists Class I–II, were stochastically allocated to control group (group C) and two DEX groups (group D1 and group D2). In group D1 and group D2, DEX (0.5 and 1.0 µg/kg, respectively) was administrated 10 min before induction of general anesthesia. In group C, equivalent saline was infused by the same way. We monitored heart rate (HR), blood pressure, and train-of-four (TOF) values of all subjects in the period of anesthesia. We recorded times to reach TOF value 0 (T0, from injection of ROC to disappearance of all four twitches) as the onset time and TOF value 25% (T25, ratio of fourth twitch to first twitch,) as clinical duration of neuromuscular blockade. A total of 81 patients were randomized, 75 of whom accepted treatment, including group D1 ( n = 25), D2 ( n = 25), and C ( n = 25). T0 time of three groups was found to be similar. The duration of action for ROC in group D2 was 62.76 ± 6.33 min, which was much longer than that in group D1 and group C, which were 42.64 ± 3.92 and 42.56 ± 4.04 min ( p < 0.05), respectively. At T2 (after DEX administration) and T4 time point (10 min after trachea intubation), compared with group C, the changes of heart rate (HR) and blood pressure in DEX groups (group D1 and group D2) show greatly differences. Otherwise, there were no obvious differences among different groups at the other monitoring point-in-time. DEX infusion in general anesthesia has no obvious effect on the onset of ROC, but it is capable of prolonging its clinical effect time, which can provide reference for rational application of DEX and ROC in general anesthesia.