Hemodynamic changes in normovolemic and hypovolemic canines during epidural block]

Hemodynamic changes were studied in normovolemic and hypovolemic canines during epidural block. In normovolemic canines after epidural block, stroke volume (SV) increased, heart rate (HR) slowed down and total peripheral resistance (TPR) and mean arterial pressure (MAP) decreased. In addition, hepatic vascular resistance (HVR) and renal vascular resistance (RVR) decreased but quantity of hepatic artery per beat (QHR/HR), quantity of hepatic artery per beat (QPV/HR) and quantity of renal artery per beat (QRA/HR) increased significantly. In hypovolemic canines, the hemodynamic changes after epidural block were similar in normovolemic ones but more abrupt. The increase of QHA/HR, QPV/HR and QRA/HR was not statistically significant, but minute hepatic blood volume quantity of hepatic artery (QHA), quantity of portal vein (QPV) and hepatic blood flow (HBF) decreased significantly. In hypovolemic canines during epidural block, ischemic injury of the liver should be alerted and abrupt hemodynamic changes should be well controlled.