Increased neutrophil elastase, persistent intravascular coagulation, and decreased fibrinolytic activity in patients with posttraumatic acute respiratory distress syndrome

Background: To investigate the role of plasma neutrophil elastase (elastase-alpha 1-proteinase inhibitor complex), plasminogen activator inhibitor-1 (PAI-1), and disseminated intravascular coagulation (DIC) in patients with posttraumatic acute respiratory distress syndrome (ARDS) and to explore the time course of the changes of these factors after trauma, we performed a prospective case-control study. Methods: The study subjects consisted of 41 trauma patients, 5 with ARDS, 7 at risk for but not developing the syndrome, and 29 control patients without or with no risk for ARDS. Plasma neutrophil elastase, PAI-1 activity, and PAI-1 antigen concentration were measured on the day of the injury and on days 1, 3, and 5 after admission. DIC was measured on the basis of the DIC score. The results of these measurements and demographic data were compared among the three groups. Results: Neutrophil elastase, PAI-1 activity, and PAI-1 antigen concentration for the ARDS patients continued to be markedly high until the fifth day of admission, and the values on the fifth day were significantly higher than those of the other two groups. All patients with ARDS developed DIC. A decrease in the DIC score was found for the control patients and also for the patients at risk for ARDS; however, for the patients with ARDS, the DIC score did not improve during the study period (p = 0.5809). Conclusion: We provide precise information on the time course of neutrophil elastase, PAI-1, and DIC in trauma patients with ARDS and those at risk of developing this syndrome. Neutrophil activation and persistent intravascular coagulation as well as impaired fibrinolysis may play a role in the pathogenesis of posttraumatic ARDS.