Hepatic blood flow and cardiac output during Fluoromar anaesthesia. An animal study

Related values of cardiac output and hepatic blood flow were measured in eight premedicated (pethidine 10 mg/kg b.w.) dogs under varying depths of fluoromar anaesthesia. The measurements were first taken under basis anaesthesia with barbiturate (mebumal natrium 25 mg/kg b.w.) gallamine (80 mg)-N2O-O-O2 (ratio 2 to 1) with controlled normoventilation, and then under increasing depths of fluoromar anaesthesia: increasing stepwise to 1 1/2-3 and 6% inspiratory concentrations. Finally the measurements were repeated after the fluoromar had been discontinued. Using the basis anaesthesia as a reference, it was found that 6% fluoromar gave a reduction in cardiac output (34%), heart rate (11%) and mean pressure in the aorta (18%). The peripheral resistance was simultaneously increased by 22%. The effect on the splanchnic blood flow was far less and without significant changes from one step in the anaesthesia to the next. Using 6% fluoromar it was found that there was a maximum reduction in blood flow of 20% of the initial value. There was unchanged splanchnic resistance during the whole of the investigation. After discontinuation of the fluoromar for 15 min and continued controlled ventilation (O2-N2O), rising heart rate and blood pressure were observed; however, cardiac output and splanchnic blood flow were unchanged. Corresponding to this, an additional increase in peripheral resistance of 10% and an insignificant increase of 5% in the splanchnic resistance were observed.