Objectives: Evaluating effect of oral labetalol pre-medication followed by low-dose intraoperative (IO) labetalol infusion on IO heart rate (HR) and mean arterial pressure (MAP), blood loss and need for transfusion and urine output (UOP) of patients undergoing open abdominal myomectomy.Patient & methods: Eighty-eight patients were randomly divided into: Study patients received 200 mg oral labetalol 2-hr before surgery and IO labetalol infusion (0.2mg/kg/hr) till completion of myomectomy. Control patients received placebo infusion and all patients received the same anesthetic protocol.Results: Operative blood loss and transfusion needs were significantly lower, but UOP was significantly higher in study than control patients. Oral labetalol significantly decreased preoperative HR and MAP of study patients compared to their baseline measures and to control patients. Oral labetalol significantly decreased HR and MAP elevations after induction and intubation compared to control patients. Labetolol infusion significantly decreased HR and MAP till stoppage of infusion compared to other measures and to control patients. Labetalol infusion allowed stability of HR and MAP with non-significant difference between measures till stoppage of infusion. Extubation significantly elevated HR and MAP in control patients, but non-significantly in study patients. Postoperative (PO), HR and MAP were significantly lower in study patients compared to baseline measures and to PO measures in control patients. PO hemoglobin concentration was significantly lower in all patients than preoperative concentrations, but concentration deficit was significantly lower in study than control patients.
Conclusion:The applied protocol of labetalol hypotensive anesthesia improved anesthetic and surgical outcome of myomectomy.