ObjectiveThe aim of this study was to investigate the direct influence of lung contusion on pulmonary surfactant in multiple trauma patients.DesignProspective, nonrandomized study.SettingUniversity hospital, trauma intensive care unit.Patients19 were studied prospectively.InterventionsBronchoalveolar lavage was performed daily until either day 7 or extubation. Samples from the side of lung contusion (n = 62) and the contralateral, uninjured side (n = 62) were obtained at the same time in 14 patients. Total phospholipids, total phospholipid classes, and surfactant apoprotein A were quantified. Additionally, surfactant function was measured with a pulsating bubble surfactometer in four patients. All data are presented as mean +/- SEM. Statistical analyses were performed using programs of SPSS for Windows 6.1.3 (SPSS Inc., Chicago, IL) (Student's t-test; p < .05).Measurements and Main ResultsTotal phospholipids were significantly increased on the side of lung contusion (contusion side, 40 +/- 7 [micro sign]g/mL; contralateral side, 21 +/- 3 [micro sign]g/mL; p = .004). The percentage contents of phosphatidylcholine (contusion side, 87.1% +/- 1.0%; contralateral side, 84.3% +/- 1.0%; p = .04) and sphingomyelin (contusion side, 2.9% +/- 0.3%; contralateral side, 1.9% +/- 0.2%; p = .004) were significantly higher. In contrast, the percentage content of phosphatidylglycerol was significantly decreased (contusion side, 4.1% +/- 0.1%; contralateral side, 6.9% +/- 0.6%; p = .001). No alterations were found for the relative contents of phosphatidylethanolamine (contusion side, 2.4% +/- 0.2%; contralateral side, 2.2% +/- 0.2%; p = .47), phosphatidylinositol (contusion side, 3.5% +/- 0.4%; contralateral side, 4.6% +/- 0.5%; p = .06), and surfactant apoprotein A (contusion side, 7177 +/- 1404 ng/mL; contralateral side, 4513 +/- 787 ng/mL, p = .10). There was no statistical difference for minimal surface tension measured with the pulsating bubble surfactometer after 5 mins of oscillation (contusion side, 29.5 +/- 2.3 mN/m; contralateral side, 23.7 +/- 2.1 mN/m; p = .08).ConclusionsDirect damage of lung parenchyma by lung contusion alters the composition of surfactant. No additional changes in surfactant function were observed that would argue in favor of functional compensation. (Crit Care Med 1999; 27:1441-1446)