[Effect of esmolol on propofol dose requirement for anesthesia in thyroidectomy]

To observe the effect of esmolol application before and during operation on propofol dose required for anesthesia induction and maintenance.

Forty patients (ASA physical status I or II) undergoing general anesthesia for thyroidectomy were randomized equally into esmolol and control groups. Patients in esmolol group received a loading dose of esmolol at 0.5 mg/kg in 30 ml normal saline over a period of 5 min followed by an intravenous infusion of esmolol at 50 microg.kg(-1).min(-1) until the end of surgery, while patients in the control group were given normal saline in the same manner, in addition to anesthesia with protofol. Perioperative hemodynamic parameters and BIS were measured, and the duration of anesthesia, operation and recovery time from anesthesia were recorded.

There were significant differences between the two groups in propofol dose required for anesthesia induction and recovery time from anesthesia, but not in maintenance propofol dose. Patients in esmolol group had significantly lower HR and BIS during tracheal intubation than those in the control group , and no significant differences were found in HR, BP and BIS during operation between the two groups. The hemodynamic parameters during extubation showed less fluctuation in esmolol group.

Perioperative esmolol administration during anesthesia reduces propofol dose required for anesthesia induction and recovery time from anesthesia, and decreases HR and BIS variation during tracheal intubation and hemodynamic response during extubation without affecting the maintenance propofol dose.