The effect of seven vasopressors on halothane mac in dogs

Abstract

Summary: We evaluated the effects of ephedrine, mephentermine, metaraminol, phenylephrine, methoxamine, noradrenaline and adrenaline on halothane anaesthetic requirement (MAC) in dogs. MAC increased significantly only during ephedrine infusion (50%) although significance was approached with mephentermine (21%). Phenylephrine, metaraminol, methoxamine, noradrenaline and adrenaline did not change MAC. Arterial pressure was increased 50-100% with all agents. Our results support the hypothesis that anaesthetic requirement may be related, in part, to release of brain noradrenaline. © 1975 Macmillan Journals Ltd.