Effect of varying concentration of ethanol on systemic hemodynamics and regional circulation

The effect of ethanol (0.5 g/kg, IV) at different concentrations (30%, 60%, and 90%) was studied in male cats using radioactive microspheres on systemic hemodynamics and regional circulation. Ethanol produced a significant fall in systolic, diastolic and mean blood pressure. A significant reduction in heart rate, left ventricular work, cardiac output and total peripheral resistance was also observed. No change occurred in stroke volume. A significant decrease in blood flow to left ventricle, right ventricle and interventricular septum was observed, but the vascular resistance of these regions was unaltered. Brain blood flow was not affected by various concentrations of ethanol. The vascular resistance significantly decreased in spinal cord, medulla, pons, midbrain, hypothalamus, thalamus, caudate nucleus, cerebellum and cortex. The average brain blood flow (ml/min/100 g) was 35.63 in control, 37.17 in 30%, 35.56 in 60% and 35.05 in 90% ethanol-treated cats. Spleen, liver, pancreas, gastrointestinal tract, skin, muscle and bone did not show any significant change in the blood flow, while vascular resistance following ethanol treatment. The blood passing through the arteriovenous shunts was significantly decreased by ethanol. It is concluded that ethanol produces marked cardiovascular changes which are not affected by varying the concentration of ethanol.