Effects of esmolol on time-to-action of rocuronium and hemodynamics in patients during anesthesia induction

Objective To study the effects of esmolol on time- to- action of rocuronium and hemodynamics in patients during perioperative period. Methods Sixty patients scheduled for elective noncardiac surgery in our hospital between February and September 2005 were randomly divided into group E and group C (n=30 each). After anesthesia induction, 0.5 mg/kg esmolol was intravenously injected in group E, and 10 ml normal saline in group C. 0.6 mg/kg rocuronium was given intravenously after 1 min, and tracheal intubation was then performed at 6 min after injection of esmolol or saline. The hemodynamic changes and time- to- action of rocuronium in two groups were recorded at different time spots: before anesthesia induction (Tb), before injection of esmolol or normal saline (T0), at 1 min (T1), 2 min (T2), 3 min (T3), 4 min (T4) and 5 min (T5) after injection. Results Between T2 and T5 time spots, both heart rate (HR) and cardiac output (CO) of group E were significantly lower than those of group C (all P＜0.05). The HR, CO and mean arterial blood pressure (MABP) of group E were remarkably declined after esmolol injection from T1 to T5 time spots compared with T0 (all P＜0.05). In addition, the time-to-action of rocuronium in group E was obviously prolonged in comparison with that in group C [( 120±6)s vs (88±4)s,P＜0.001]. Conclusion Along with the decline in MABP, HR and CO, esmolol may prolong the time-toaction of rocuronium significantly. Key words: Esmolol;  Rocuronium;  Drug interactions;  Neuromuscular blocking agents; Hemodynamics