Oxygen affinity of erythrocytes and pulmonary gas exchange in patients on continuous ambulatory peritoneal dialysis.

In 11 patients on continuous ambulatory peritoneal dialysis 2,3-diphosphoglycerate, oxygen (O2) affinity of red cells (P50), blood gases, ventilation, and O2 consumption were studied. Contrary to patients on maintenance hemodialysis, 2,3-diphosphoglycerate and P50 were normal in patients on continuous ambulatory peritoneal dialysis; they were correlated with each other. Arterial O2 pressure was normal; under the conditions of dialysis with 35 mmol lactate per liter dialysis fluid a slight metabolic acidosis persisted; it was combined with a moderate respiratory alkalosis. Position had no influence upon pulmonary gas exchange with the exception of the alveolo-arterial gradient which was elevated when the abdominal cavity was filled with dialysis fluid and the patients assumed the supine position. Ventilation was in the normal range, whereas O2 consumption was low, possibly due to a reduction in muscle mass in some of the patients. It is concluded that pulmonary gas exchange and erythrocyte O2 transport were normal and that O2 requirements tended to be low in this group of patients on continuous ambulatory peritoneal dialysis.