Local effect of lung contusion on lung surfactant composition in multiple trauma patients

Objective: The aim of this study was to investigate the direct influence of lung contusion on pulmonary surfactant in multiple trauma patients. Design: Prospective, nonrandomized study. Setting. University hospital, trauma intensive care unit. Patients: Eighteen multiple trauma patients with unilateral lung contusions and Injury Severity Scores >19 were studied prospectively. Interventions: Bronchoalveolar 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 Results: Total phospholipids were significantly increased on the side of lung contusion (contusion side, 40 +/- 7 mu g/mL; contralateral side, 21 +/- 3 mu 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, 29% +/- 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), Conclusions Direct 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.