Recovery from lung injury in survivors of acute respiratory distress syndrome: difference between pulmonary and extrapulmonary subtypes

Objective: To determine whether long-term outcome differs between acute respiratory distress syndrome ( ARDS) resulting from pulmonary (ARDSp) and extrapulmonary (ARDSexp) causes. Design: Observational study. Setting: Medical intensive care unit of a university hospital. Patients: Twenty-nine ARDS patients ( 16 ARDSp and 13 ARDSexp) who survived over 6 months after diagnosis. Measurements and results: The two groups did not differ according to demographic data and severity indices on admission. The duration of ICU stay ( median 21 days [interquartile range, 12 - 43 days] vs 12 [6.5 - 20] days, p = 0.097) tended to be longer and total ventilation time ( 360 [ 96 - 700] h vs 144 [42.5 - 216] h, p = 0.045) were longer in the patients with ARDSp. The ARDSp patients showed more severe abnormalities on thin-section computed tomography (CT), including ground-glass opacity (GGO; 6 [ 3 - 16] vs 0 [ 0 - 2.5], p = 0.002), reticular density ( 12 [ 8 - 14] vs 5 [ 2 - 9], p = 0.033) and the sum of all four patterns of lesion ( 20 [ 11 - 27] vs 5 [ 2 - 12], p = 0.006). There were no between-group differences in Spitzer's Quality of Life index and the Chronic Respiratory Questionnaire. Conclusions: These results suggest that ARDSp would leave more severe lung sequelae than ARDSexp, but the clinical relevance of their difference is questionable.