Pulmonary diffusing capacity in chronic renal failure.

Reduced carbon monoxide diffusing capacity (DLCO) is a frequent and often isolated pulmonary physiological abnormality in patients with chronic renal failure. In 20 patients with chronic renal failure who had normal spirometry (FEV1 and FVC greater than 80% of predicted) and near normal chest roentgenograms (three had mild cardiomegaly), the DLCO was significantly reduced compared to values obtained from 25 healthy laboratory staff and renal transplant donors. DLCO and diffusing capacity standardized for alveolar volume (KCO) remained reduced after correction for anaemia. No relationship between anaemia and severity of reduction of DLCO was demonstrated. These observations suggest that in addition to anaemia and ventilatory abnormalities, there may be other factors causing a reduced DLCO in chronic renal failure.