Use of labetalol during halothane anaesthesia.

The drugs that are available to attain controlled hypotension during anaesthesia are not entirely satisfactory. Problems in controlling hypotension are encountered in the young, the anxious, patients with a tachycardia, and in those for whom halothane is contra-indicated. Labetalol has been investigated as an adjunct to controlled hypotension in 150 major surgical procedures. Anaesthetic technique, labetalol dosage and results are discussed. Labetalol in patients under halothane anaesthesia resulted in a rapid attainment of hypotension which was easily controlled, and quickly and permanently reversed by the intravenous administration of atropine sulphate. It was especially useful in patients in whom problems with other techniques can be anticipated. Controlled hypotension with labetalol was also used in patients with ischaemic heart disease with good cardiovascular control and without any untoward effects.