To determine outcome in young, healthy blunt trauma patients with isolated pulmonary contusion, and to identify factors associated with poor outcome, we reviewed 6012 consecutive adult (aged 16-49) blunt trauma admissions. Ninety-four (7.9%) presented with an isolated pulmonary contusion defined by chest radiograph and Injury Severity Score < 25; they compromise the study group. Poor outcome was defined as death, prolonged hospitalization (> 7 days), or a severe complication (pneumonia, empyema, atelectasis requiring bronchoscopy, or bronchopleural fistula). None of the 94 study patients died. Admission chest radiograph demonstrated no contusion in 34 patients (36%). Fifteen patients (16%) required intubation, but 13 were extubated within 48 hours. Forty-one patients (44%) required insertion of a chest tube, and 20 patients (21%) had a PaO2/FiO2 ratio of < 250 on admission. Post-injury atelectasis (n = 17), pneumothorax (n = 17), effusion (n = 8), pneumonia (n = 2), empyema (n = 1), and Staphylococcal bacteremia (n = 1) complicated hospitalizations. The following clinical factors were identified as predisposing to poor outcome by univariate analysis: 1) Pulmonary contusion on admission chest radiograph (P = 0.035); 2) Three or more rib fractures (P = 0.002); 3) chest tube insertion (P = 0.010) and drainage (P = 0.020); and 4) hypoxia on admission (PO2 < 70 torr [P = .021], PaO2/FiO2 < 250 [P < 0.001]). Only PaO2/FiO2 < 250 on admission was an independent predictor of poor outcome in a multivariate analysis (P = 0.040). Our conclusion was that isolated pulmonary contusion in young, healthy patients is not associated with mortality.(ABSTRACT TRUNCATED AT 250 WORDS)