Prediction of pulmonary function abnormalities after adult respiratory distress syndrome (ARDS)

To determine if measures of ARDS severity during the acute illness correlate with lung function after recovery from ARDS, we regressed lowest total thoracic compliance (CTH), initial intrapulmonary shunt fraction (Qsp/Qt), initial mean pulmonary artery pressure (PAP), maximal level of positive end-expiratory pressure (PEEP), time ventilated (Tvent), and time with FlO2 greater than 0.6 (TO2) against the percent of predicted FVC, TLC, and DLCO of 16 previously healthy, nonsmoking ARDS survivors. Pulmonary function tests were performed more than 1 yr after ARDS. Percent of predicted FVC correlated with CTH (r = 0.66, p less than 0.01) and PAP (r = 0.53, p less than 0.05), and percent of predicted TLC correlated with CTH (r = 0.71, p less than 0.01), PEEP (r = -0.55, p less than 0.05), and Qsp/Qt (r = -0.53, p less than 0.05). Only TO2 correlated with percent of predicted DLCO (r = -0.53, p less than 0.05). Five of 7 ARDS survivors with an abnormal DLCO were supported at FlO2 greater than 0.6 for more than 24 h, whereas all of 9 survivors with a normal DLCO received FlO2 greater than 0.6 for less than 24 h. We conclude that physiologic markers of ARDS severity during the acute illness correlate with residual pulmonary dysfunction after recovery from ARDS. Support with FlO2 greater than 0.6 for more than 24 h appears to be a sensitive and specific predictor of an abnormally reduced DLCO more than 1 yr after ARDS.