Portal and systemic haemodynamic action of N-acetylcysteine in patients with stable cirrhosis.

The effects of intravenous N-acetylcysteine on hepatic and systemic haemodynamics were investigated in 11 patients with stable cirrhosis (eight alcohol; two primary biliary cirrhosis; one cryptogenic). N-acetylcysteine administration had no effect on the mean heart rate or mean arterial blood pressure despite a significant fall in systemic and pulmonary vascular resistance. Cardiac index increased but estimated liver blood flow and portal venous pressure did not change significantly. Administration of N-acetylcysteine resulted in increased oxygen delivery to the tissues because of the increased cardiac index but this was not accompanied by a rise in either arteriovenous oxygen extraction ratio or mean tissue oxygen consumption. Therefore N-acetylcysteine administration seems to confer no haemodynamic benefit to patients with cirrhosis.