Effects of Induced Hypotension with Labetalol on Blood Loss and Blood Pressure in Maxillofacial Surgical Patients

Lee, Jun Rae

Abstract

BACKGROUND: The worst problem in anesthetic management of maxillofacial surgery is bleeding from bone cutting site. Induced hypotension reduces bleeding and minimizes the need for blood transfusion. This study was performed to evaluate the effects of induced hypotension with labetalol on blood loss and blood pressure in maxillofacial surgical patients.
METHODS
Twenty-four adult patients, either sex, ASA physical status I or II, undergoing orthognathic surgery were randomly selected and divided into two groups; one group was administered 20 mg of labetalol and the other group was not. Anesthetic maintenance was consisted of O2-N2O-enflurane (2~2.5 vol%). Then 20 mg of labetalol was given intravenously at skin incision time in the labetalol group. Hemodynamic variables were recorded before induction of anesthesia, at the beginning of the labetalol infusion and at 10 min, 20 min, 30 min, 60 min and 90 min after the infusion. Blood loss determined by measuring the weight of the sponges and by measuring the volume of blood in suction-trap bottle.
RESULTS
There was no significant difference in preoperative hemoglobin and postoperative hemoglobin between two groups. The amount of blood loss in the labetalol group (408 +/- 202 ml) was less than those in the control group (450 +/- 255 ml), but statistically not significant. The blood pressure was significantly decreased in the labetalol group than those of the control group at 20 minutes after the labetalol infusion.
CONCLUSIONS
Labetalol is a useful agent for inducing hypotension. But 20 mg of labetalol was insufficient to decrease the blood loss. So I think the more amount of labetalol required to reduce the blood loss.