Effects of dexmedetomidine on the onset time and clinical duration of rocuronium

Objective To investigate effects of dexmedetomidine on the onset time and clinical duration of rocuronium. MethodsA total of 40 ASA Ⅰ-Ⅱ patients aging 25-55 who scheduled for laparoscopic surgery under combined anesthesia were divided into a dexmedetomidine group and a control group (n=20). Anesthesia induction was conducted through intravenous injection of 0.4 μg/kg sufentanil, 2 mg/kg propofol and 0.6 mg/kg rocuronium. Before anesthesia induction, the dexmedetomidine group was intravenously injected with 0.5 μg/kg dexmedetomidine within 10 min, followed by intravenous infusion of 0.5 μg·kg-1·h-1 dexmedetomidine during anesthesia. The control group was injected with the same volume of normal saline. The onset time and clinical duration of rocuronium were recorded. The blood pressure and heart rate (HR) were recorded before treatment (T0), after dexmedetomidine injection (T1), before intubation (T2), immediately after intubation (T3), 5 min after intubation (T4),10 min after intubation (T5), and 30 min after intubation (T6). The onset time and non-response time of rocuronium were recorded using the four-train stimulation (TOF). ResultsThere were no significant difference in terms of the onset time and non-response time of rocuronium, systolic and diastolic pressures between the two groups (all P>0.05). The control group showed remarkable decreases in HR on T2 and T6 compared with those on T0 (all P<0.05). The dexmedetomidine group presented significantly reduced HR on T1, T2, T4, T5 and T6, while the control group showed markedly reduced HR on T5 (all P<0.05). ConclusionsA small dose of dexmedetomidine does not affect the onset time and clinical duration of rocuronium but may present stronger effects on HR.　
Key words: dexmedetomidine; neuromuscular blockade; rocuronium