Cardiac output and liver blood flow in humans: effect of the volatile anesthetic halothane.

In 40 men with normal circulatory and liver function, from whom 10 were undergoing general anesthesia with halothane for minor orthopedic surgery, the relationship between hemodynamic parameters and total hepatic blood flow (HBF) was investigated. Cardiac output (CO) was measured noninvasively by means of the thoracic electrical bioimpedance method, systemic arterial blood pressure (BPsys, BPdia, mean arterial pressure) by an automated oscillometric device and HBF by indocyanine green clearance. In the subjects without halothane anesthesia no relationship was found between BP and HBF, but a significant correlation could be seen between CO and HBF, whereby the fraction of HBF decreased with increasing CO. In contrast, in the presence of halothane the systemic arterial blood pressure correlated with the HBF, indicating a loss of autoregulation of the liver circulation.