Pulmonary function in chronic renal failure patients managed by continuous ambulatory peritoneal dialysis.

The influence of intraperitoneal fluid on pulmonary function was studied in 20 unselected continuous ambulatory peritoneal dialysis (CAPD) patients, all but one of whom had at least one cardiorespiratory disorder. Measurements of pulmonary function were made with the abdomen empty and following the instillation of 2 1 of dialysis fluid (full). Functional residual capacity fell with the peritoneal cavity full, due to decreases in residual volume, and expiratory reserve volume, but there was a corresponding increase in inspiratory capacity. The vital capacity remained unchanged and the total lung capacity fell only slightly. The FEV1, diffusing capacity, and distribution of ventilation were unaltered. These findings can be attributed to an increase in intra-abdominal pressure resulting in elevation of the diaphragm and increased diaphragmatic contractility. We conclude that the instillation of 21 of dialysis fluid in CAPD patients with cardiorespiratory disease does not result in a clinically significant deterioration in these aspects of pulmonary function.