Systemic activation of tissue-factor dependent coagulation pathway in evolving acute respiratory distress syndrome in patients with trauma and sepsis.

Background: Extravascular coagulation and fibrin deposition coupled with perturbations of intravascular coagulation occurs in association with acute respiratory distress syndrome (ARDS). To evaluate the pathogenetic role of an extrinsic coagulation pathway in the intravascular coagulation of ARDS patients and to explore the time course of the changes of tissue factor levels, platelet counts, and disseminated intravascular coagulation (DIC), we performed a prospective cohort study. Methods: The study subjects consisted of 113 patients: 27 patients with ARDS, 31 patients at risk for but not developing the syndrome, and 55 patients without ARDS. According to the underlying disease, the patients were further subdivided into two groups: patients with trauma (n = 76) and patients with sepsis (n = 37). Ten normal healthy volunteers served as control subjects. Plasma tissue factor antigen (tissue factor) levels and platelet counts were measured on the day of admission and on days 1 through 4 after admission. Simultaneously, the DIC scores were determined. Results: The values of tissue factor in the patients with ARDS were significantly more elevated than those measured in the other two groups (p < 0.001) and control subjects (p < 0.001) on the day of admission. The values continued to be markedly high up to day 4 of admission. On the day of admission, the platelet counts in the ARDS patients showed significantly lower values (p < 0.05) than those in the other two groups. The incidence of DIC and the DIC scores in ARDS patients were significantly higher than those in the other two groups. The tissue factor levels (r s = 0.428, p < 0.0001) and DIC scores (r, = 0.357, p < 0.0002) correlated significantly with Lung Injury Score. When the patients were subdivided into two subgroups, i.e., trauma and sepsis, some differences of the tissue factor levels were noted between the two groups. Conclusion: We demonstrated that tissue-factor dependent coagulation pathway of plasma is extensively activated in patients with ARDS, followed by intravascular coagulation and platelet consumption. We further provide precise information on the time course of tissue factor levels and DIC in patients with ARDS and those at risk for developing this syndrome.