Pulmonary function in chronic renal failure

Pulmonary function studies both before and after dialysis were performed on a group of 32 patients with chronic renal failure (CRF) who were undergoing either hemodialysis or peritoneal dialysis. Maximum expiratory flow volume curves were obtained with subjects breathing first air (A) and then a mixture of 80 per cent helium (He) and 20 per cent oxygen. A fixed restrictive pulmonary function pattern, characterized by a reduced forced vital capacity (FVC) and 1 second forced expiratory volume (FEV₁) with normal FEV₁/FVCx100, was demonstrated in all subjects but was more marked in those undergoing peritoneal dialysis. There was no consistent improvement in pulmonary function following dialysis despite significant fluid loss, with the exception of a small increase in the maximum expiratory flow at 50 per cent of FVC while breathing air. The authors conclude that there is a fixed restrictive pulmonary abnormality in patients with CRF which is largely independent of fluid balance status.