Studies on morphine disposition: influence of general anaesthesia on plasma concentrations of morphine and its metabolites.
A study of 88 patients showed a reduction in the estimated hepatic blood flow (EHBF), as measured by a colloidal gold technique, to 88% and 84% of its initial value during ether and halothane anesthesia, respectively. During the operative procedure itself, there was a further fall in the EHBF. In patients undergoing herniorrhaphy or excision of a breast tumor, the EHBF decreased to 82% and 76%, while in patients undergoing partial gastrectomy or cholecystectomy, the EHBF fell to 48% and 42% of its initial value during operations under ether and halothane anesthesia, respectively. The surgical trauma itself would appear to be the main determinant of the alteration in the liver circulation during the operation.