Oxygen Affinity of Erythrocytes and Pulmonary Gas Exchange in Patients on Continuous Ambulatory Peritoneal Dialysis

Abstract

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.