Hemodynamic changes during induction of anesthesia with eltanolone and propofol in dogs.

The purpose of this study was to examine global and regional hemodynamic changes during induction of anesthesia with eltanolone, a new short-acting steroid hypnotic, as compared to propofol, in chronically instrumented dogs. The effects on cardiac performance were assessed in six animals. Renal and hepatic blood flows were examined in a separate study including five animals. Two doses of each drug were investigated: eltanolone 2.5 and 5 mg/kg and propofol 7.5 and 15 mg/kg. Left atrial filling pressures and cardiac output were not affected by either drug. Maximum rate of increase of left ventricular pressures decreased both with eltanolone (-28% and -40% from awake control for the 2.5 and 5 mg/kg doses, respectively) and with propofol (-19% and -30% from awake controls with 7.5 and 15 mg/kg respectively). In contrast to propofol, eltanolone preserved arterial blood pressure. Propofol lowered systemic vascular resistance (-21% and -39% with the low and high dose, respectively), and only slightly decreased left ventricular wall thickening fraction (-16% and -21%). Eltanolone did not affect systemic vascular resistance but reduced the wall-thickening fraction dose-dependently (-28% and -61%). Propofol, but not eltanolone, induced moderate coronary vasodilation. Hepatic arterial blood flow velocity decreased dose-dependently (-21% and -64%) during eltanolone anesthesia whereas, in contrast, it increased after propofol (+59% and +64%). Renal and portal venous blood flows remained essentially unaltered from awake conditions.(ABSTRACT TRUNCATED AT 250 WORDS)

Global and regional haemodynamic effects of urapidil in conscious dogs with chronic coronary artery occlusion.

The haemodynamic effects of urapidil, an alpha 1-antagonist with central serotoninergic properties, were studied in an experimental canine model of chronic ischaemic heart disease. Global and regional haemodynamic recordings were made in conscious dogs with ameroid-induced single vessel coronary artery occlusion. Three intravenous bolus-infusion doses of urapidil (0.1 mg kg-1 + 0.3 mg min-1; 0.5 mg kg-1 + 1.5 mg min-1; 2.5 mg kg-1 + 7.5 mg min-1) were given on separate occasions in 12 animals. Regional blood flows were measured with radioactively labelled tracer microspheres. The effects of urapidil and dipyridamole, a powerful arteriolar vasodilator, on regional myocardial blood flow distribution to normal and collateral-dependent myocardium were compared. Urapidil caused a dose-dependent reduction of arterial blood pressure. There was moderate tachycardia and decreased left atrial filling pressures at the higher doses. Urapidil was a much weaker coronary vasodilator than dipyridamole. Dipyridamole caused maldistribution of intercoronary and transmural flows (endo-to-epicardial flow ratio in collateral-dependent regions from 1.35 +/- 0.07 to 0.7 +/- 0.13 and flow ratio between collateral-dependent and normal regions from 1.09 +/- 0.03 to 0.57 +/- 0.14). Urapidil preserved blood flow to both regions. Urapidil did not affect systolic wall thickening fraction in normal or ischaemic regions of the heart. Renal (+16%) and splanchnic perfusion (+45%) increased during urapidil infusion. Urapidil preserves myocardial function and perfusion and increases renal and intestinal blood flow in dogs with chronically ischaemic hearts.