Deliberate hypotension induced by labetalol with halothane, enflurane or isoflurane for middle‐ear surgery

Abstract

The feasibility of using labetalol, an alpha- and beta-adrenergic blocking agent, as a hypotensive agent in combination with inhalation anaesthetics (halothane, enflurane or isoflurane) was studied in 23 adult patients undergoing middle-ear surgery. The mean arterial pressure was decreased from 86 +/- 5 (s.e. mean) mmHg to 52 +/- 1 mmHg (11.5 +/- 0.7 to 6.9 +/- 0.1 kPa) for 98 +/- 10 min in the halothane (H) group, from 79 +/- 5 to 53 +/- 1 mmHg (10.5 +/- 0.7 to 7.1 +/- 0.1 kPa) for 129 +/- 11 min in the enflurane (E) group, and from 80 +/- 4 to 49 +/- 1 mmHg (10.7 +/- 0.5 to 6.5 +/- 0.1 kPa) for 135 +/- 15 min in the isoflurane (I) group. The mean H concentration during hypotension in the inspiratory gas was 0.7 +/- 0.1 vol%, the mean E concentration 1.6 +/- 0.2 vol%, and the mean I concentration 1.0 +/- 0.1 vol%. In addition, the patients received fentanyl and d-tubocurarine. The initial dose of labetalol for lowering blood pressure was similar, 0.52-0.59 mg/kg, in all the groups. During hypotension, the heart rate was stable without tachy- or bradycardia. The operating conditions regarding bleeding were estimated in a double-blind manner, and did not differ significantly between the groups. During hypotension, the serum creatinine concentration rose significantly in all groups from the values before hypotension and returned postoperatively to the initial level in the other groups, except the isoflurane group. After hypotension there was no rebound phenomenon in either blood pressure or heart rate. These results indicate that labetalol induces easily adjustable hypotension without compensatory tachycardia and rebound hypertension.

The Effect of the Total Intravenous Anesthesia Compared with Inhalational Anesthesia on the Surgical Field during Endoscopic Sinus Surgery

“…10 Rebound hypertension, reflex tachycardia, vasodilation, and myocardial depression are some of the commoner problems that have been encountered. 11,13,14 During the past 20 years, major advances have taken place with regard to i.v. infusion anesthesia.…”

Evaluation of the efficacy of desflurane with or without labetalol for hypotensive anesthesia in middle ear microsurgery

“…[ 7 ] Similar results have been reported by other investigators. [ 1 12 13 14 ] Saarnivaara et al . used labetalol and halothane to induce hypotension without any compensatory rise in HR.…”

“…[ 12 ] Combination of labetalol with halothane, enflurane, or isoflurane was found to result in a stable HR during induced hypotension. [ 13 ]…”

“…Both desflurane and labetalol have been successfully used to attain the desired MAP for providing hypotensive anesthesia. [ 13 15 16 17 18 ] In fact, combining labetalol with inhalational agents produces a remarkable hypotensive synergism; labetalol is less potent in this regard when combined with intravenous anesthetics. [ 19 ]…”

Effects of deliberate hypotension induced by labetalol with isoflurane on neuropsychological function

“…Labetalol, an alpha-and beta-adrenergic receptor blocking agent (1)(2)(3), has been used as an antihypertensive drug (2) and also to cause deliberate hypotension (4). Labetalol is also used with isoflurane to induce hypotension (4).…”