Oxygen Affinity of Hemoglobin and Red Cell 2,3-Diphosphoglycerate in Hepatic Cirrhosis

The level of 2,3-diphosphoglycerate (2,3-DPG) in erythrocytes was found to be increased in patients with cirrhosis of the liver, and as a consequence the oxygen affinity of hemoglobin was decreased. Part of the 2,3-DPG increase in the patients with cirrhosis was caused by a concomitant anemia. At all hemoglobin levels, however, patients with cirrhosis showed an additional 2,3-DPG increase in comparison with patients without cirrhosis. Red cell 2,3-DPG was positively correlated to pH in plasma and in erythrolysate. It is likely that pH changes contribute to the regulation of the red cell 2,3-DPG concentration in cirrhotic patients. In a group of these patients (n=48), the arterial pH and pCO2 did not differ significantly from normal values. Other, as yet unknown, factors must presumably contribute to the increase in red cell 2,3-DPG. No direct effect of NH4+ on red cell 2,3-DPG could be demonstrated in vitro. The plasma concentration of NH4+ in vivo correlated positively to plasma pH. The lowered oxygen affinity does not contribute significantly to the decrease in oxygen saturation of arterial blood often found in patients with hepatic cirrhosis.