title: Effects of ephedrine on haemodynamics and oxygen consumption in the dog during high epidural block with special reference to the splanchnic region.
abstract: High lumbar epidural block was induced in seven dogs with 0.5% bupivacaine, causing a fall in mean arterial blood pressure (AP) from 19.2 +/- 3.2 to 10.5 +/- 3.2 kPa, owing to equal reductions in cardiac output (QT) and systemic vascular resistance (SVR). After the administration of ephedrine (a single injection of 200-300 micrograms X kg-1 b.w. followed by a continuous infusion of 10-20 micrograms X kg-1 b.w. X min-1) AP, QT and SVR rose to pre-epidural values. Furthermore, the hypokinetic circulation following the epidural block returned to normokinetic levels. Portal venous blood flow was increased from 16.5 +/- 6.2 to 25.5 +/- 4.3 ml X kg-1 b.w. X min-1 by ephedrine, while the hepatic arterial blood flow was unchanged and remained at its pre-epidural level. In spite of a slight rise in hepatic oxygen consumption from 1.2 +/- 0.4 to 1.6 +/- 0.6 ml X kg-1 b.w. X min-1, the percentages of oxygen extracted from the portal vein and the hepatic artery decreased significantly. It is concluded that ephedrine restores central and splanchnic haemodynamics in a desirable manner during high epidural anaesthesia.
mesh_terms: D000767:Anesthesia, Epidural; D000818:Animals; D001794:Blood Pressure / Q000187:drug effects; D002045:Bupivacaine; D002302:Cardiac Output / Q000187:drug effects; D004285:Dogs; D004809:Ephedrine / Q000494:pharmacology*; D005260:Female; D006439:Hemodynamics / Q000187:drug effects*; D008099:Liver / Q000378:metabolism; D008102:Liver Circulation / Q000187:drug effects; D008297:Male; D010101:Oxygen Consumption / Q000187:drug effects*; D011168:Portal System / Q000187:drug effects; D013152:Splanchnic Circulation / Q000187:drug effects*; D014655:Vascular Resistance / Q000187:drug effects
chemical_list: D004809:Ephedrine; D002045:Bupivacaine