CYTOKINE, COMPLEMENT, AND ENDOTOXIN PROFILES ASSOCIATED WITH THE DEVELOPMENT OF THE ADULT-RESPIRATORY-DISTRESS-SYNDROME AFTER SEVERE INJURY

Objective: The adult respiratory distress syndrome (ARDS) is a frequen t complication after severe accidental trauma. This study examines the hypothesis that increased systemic concentrations of proinflammatory cytokines, endotoxin, or complement fragments may predict the developm ent of ARDS. Design: Prospective, observational study. Setting: Two Le vel I university trauma centers. Patients: Fifteen severely injured pa tients (Injury Severity Score of greater than or equal to 25). Interve ntions: Standard emergency department, operating room, and intensive c are unit management. Measurements and Main Results: Plasma samples wer e obtained at 4-hr intervals from the time of injury and were assayed for concentrations of endotoxin, tumor necrosis factor-a, interleukin (IL)-1 beta, IL-6, IL-8, and complement fragments C3a and C4a. Hemodyn amic and oxygen metabolism variables also were measured at 4-hr interv als after injury. Seven patients developed ARDS and eight patients did not. The Pao(2)/FIO2, ratio was significantly decreased in the patien ts with ARDS compared with non-ARDS patients as early as 4 hrs postinj ury, and remained significantly decreased throughout the initial 24 hr s after severe accidental injury. Plasma IL-8, IL-6, C3a, and C4a conc entrations were markedly increased starting in the immediate postinjur y period in both ARDS and non-ARDS patients, but no significant differ ences were found between the two groups until 16 hrs after injury when plasma IL-8, C3a, and C4a concentrations became significantly higher in the ARDS group. Neither the ARDS nor non-ARDS patients showed the p resence of circulating IL-1 beta, TNF-alpha, or endotoxin at any posti njury time point. Conclusions: These results demonstrate that measurem ents of plasma concentrations of proinflammatory cytokines, endotoxin, or complement fragments are not helpful in predicting the development of ARDS after severe accidental injury.