Effects of Doxapram HCI on the Hemodynamics after Isoflurane and Nitroglycerin Induced Hypotensive Anesthesia in Dogs

Han, Jong In; Kim, Chi Hyo; Lee, Choon Hi

Abstract

Isoflurane causes little myocardial depression, rapid onset and recovery during controlled hypotensive anesthesia. Nitroglycerin, vasodilating agent, has short plasma half-life and myocardial protective effect, is easy to cantrol, and has no direct toxic effect. Doxapram hydrochloride(doxapram Hcl), respiratory stimulant, has been found to be safe and significantly potent, but also has significant pressor effect when larger doses are administered. The purpose of this study was to evaluate the effects of doxapram on the hemodynamics after isoflurane and nitroglycerin-induced hypotensive anesthesia in dogs. Hemodynamic measurement including the value of left ventricular pressure, aortic pressure, pulmonary eapillary wedge pressure, pulmonary artery pressure, heart rate, cardiac output, maximal and minimal dP/dT were determined in 8 dogs before doxapram Hcl administration, Smin, 15min and 30min after doxapram Hcl administration. 1) Left ventricular pressure and aortic pressure increased at 5min and 15min after doxapram Hcl administration but did not change significantly at 30min compared to the preadministration values. 2) Pulmonary capillary wedge pressure and pulmonary artery pressure increased significantly at Smin and 15min, but did not change significantly 30min compared to the preadministration values. 3) Heart rate increased significantly at Smin, but did not change significantly at 15min and 30min compared to the preadministration value. 4) Cardiac output and body temperature did not change significantly at 5min, 15min compared to the preadministation values. 5) Maximal dP/dT increased signifieantly at Smin and 15min, but did not change at 30min compared to the preadministration value, minimal dP/dT increased significantly at 5min, but did not change at 15min and 30min compared to the preadministration value.