SOURCES OF VENOARTERIAL ADMIXTURE IN PORTAL HYPERTENSION*

Abstract

In 18 patients with cirrhosis of the liver and two patients with extrahepatic portal hypertension, the total venoarterial admixture was determined from the alveolar-arterial oxygen tension gradient during oxygen respiration, and the right-to-left shunt was estimated with intravenous injections of tritium. Ten of the patients received intrasplenic injections of tritium for determination of portopulmonary shunt. The 2 patients with extrahepatic portal hypertension showed normal venoarterial admixture, whereas in 8 patients with cirrhosis of the liver, the venoarterial admixture exceeded 6% of the cardiac output. Results of the tritium studies indicate that intrapulmonary shunts as well as portopulmonary shunts may be operative in patients with cirrhosis of the liver. Abnormal right-to-left shunts were demonstrated in a number of such patients, and results confirm the occasional existence of considerable portopulmonary shunts in cirrhosis of the liver.