Effects of dihydroergotamine on haemodynamics and oxygen consumption in the dog during high epidural block with special reference to the splanchnic region.

Abstract

Dihydroergotamine (DHE) 0.02 mg X kg-1 was administered i.v. in 9 dogs with high epidural block. Mean arterial blood pressure was restored from 11.0 +/- 2.4 kPa to 18.8 +/- 2.5 kPa by DHE due to a near twofold increase in systemic vascular resistance while cardiac output was unchanged. Hepatic arterial blood flow was reduced by 50% by a marked increase in hepatic arterial resistance above the pre-epidural value, while portal venous blood flow remained unchanged. Hepatic oxygen consumption decreased following DHE in spite of an increase in total oxygen consumption, probably partly due to a reduction in hepatic arterial oxygen availability. The mechanism by which the arterial blood pressure is restored by DHE in dogs during high epidural block must be regarded as unfavourable, especially with respect to the liver.