Systemic and splanchnic hemodynamics of the chronic bile duct-ligated rat were characterized by radioactive microspheres. Conscious and pentobarbital sodium-anesthetized, bile duct-ligated and sham-operated rats had cardiac output and regional organ blood flows determined. The conscious bile duct-ligated rat compared with the sham-operated showed a hyperdynamic circulation with an increased cardiac output (153.3 +/- 9.8 vs. 112.6 +/- 6.0 ml/min, P less than 0.005) and portal tributary blood flow (21.32 +/- 1.43 vs. 12.79 +/- 1.47 ml/min, P less than 0.005). Pentobarbital sodium anesthesia induced marked hemodynamic changes in both sham-operated and bile duct-ligated rats. The latter group was especially sensitive to its effects; thus, comparison of cardiac output and portal tributary blood flow between anesthetized bile duct-ligated and sham-operated rats showed no significant differences. We conclude that the rat with cirrhosis due to chronic bile duct ligation is an excellent model for hemodynamic investigations but should be studied in the conscious state, since pentobarbital sodium anesthesia eliminates the hyperdynamic circulation.

To determine the effect of pentobarbital sodium anesthesia on the rat with portal hypertension due to portal vein stenosis, four groups of rats were studied. Cardiac output and regional blood flow were measured by radioactive microspheres in anesthetized and conscious sham-operated and portal-hypertensive rats. Anesthesia markedly decreased cardiac output in both sham-operated (109.7 +/- 4.6 vs. 77.8 +/- 1.4 ml/min, P less than 0.001) and portal-hypertensive rats (130.1 +/- 7.6 vs. 93.8 +/- 5.3 ml/min, P less than 0.01). In spite of this diminution in cardiac output, pentobarbital did not significantly change absolute blood flow values of splanchnic organs in either group. However, the fractions of cardiac output perfusing the splanchnic organs were significantly increased by pentobarbital in both groups because of the decrease in cardiac output: sham operated, anesthetized, 22.86 +/- 1.19% vs. conscious, 14.83 +/- 1.02%, P less than 0.001; and portal hypertensive, anesthetized, 26.67 +/- 0.71% vs. conscious, 19.07 +/- 1.44%, P less than 0.001. The hyperdynamic circulation of the portal vein-stenosed rat compared with the sham-operated rat continued to manifest itself with significantly increased portal pressure, cardiac output, and splanchnic blood flow, whether the animal was anesthetized or awake. We conclude that, despite marked hemodynamic changes induced by pentobarbital, the rat with portal vein stenosis remains a useful experimental model of portal hypertension.