The Effect of Intraoperative Labetalol on Time to Discharge

Following induction and intubation, any increase in heart rate (HR) or mean arterial pressure (MAP) \>20% of baseline will be treated with an initial intravenous bolus of esmolol 30 mg IV (30 mg in 5 ml of normal saline). An intravenous esmolol infusion will be initiated at 5mcg/kg/min after the first intravenous bolus dose and will be titrated up by 5mcg/kg/min each time HR or MAP \>20% of baseline. An intravenous bolus of placebo (normal saline 1 ml) will be administered whenever a change to the infusion rate is made.

Following induction and intubation, any increase in heart rate (HR) or mean arterial pressure (MAP) \>20% of baseline will be treated with an initial intravenous bolus of labetalol 10 mg IV (10 mg in 5 ml of normal saline). Any further increases in HR or MAP \>20% of baseline will be treated with intravenous boluses of labetalol 5 mg in 1 ml every 5 minutes as needed. An intravenous placebo infusion (normal saline) will be initiated at 5 mcg/kg/min after the first intravenous bolus dose and will be titrated up by 5 mcg/kg/min each time an additional intravenous bolus is given.

Following induction and intubation, any increase in heart rate (HR) or mean arterial pressure (MAP) \>20% of baseline will be treated with an initial intravenous bolus of fentanyl 50 mcg IV (50 mcg in 5 ml of normal saline). Any further increases in HR or MAP \>20% of baseline will be treated with intravenous boluses of fentanyl 25 mcg in 1 ml every 5 minutes as needed. An intravenous placebo infusion (normal saline) will be initiated at 5 mcg/kg/min after the first intravenous bolus dose and will be titrated up by 5 mcg/kg/min each time an additional intravenous bolus is given.

An intravenous placebo infusion (normal saline) will be initiated at 5 mcg/kg/min after the first intravenous bolus drug dose (fentanyl or labetalol depending upon randomization) and will be titrated up by 5 mcg/kg/min each time an additional intravenous bolus is given.

Every time the infusion rate of esmolol is changed, 1 ml of normal saline will be infused.