Acute respiratory distress syndrome in trauma patients:: ICU mortality and prediction factors

Objectives: To study the factors that influence the intensive care unit (ICU) mortality of trauma patients who develop acute respiratory distress syndrome (ARDS) and to evaluate determinants of length of ICU stay among these patients. Design: Study on a prospective cohort of 59 trauma patients that developed ARDS, Setting: ICU of a referral trauma center. Fifty-nine patients were included during the study period from 1994 to 1997. Methods: The dependent variables studied were the mortality and length of ICU stay. The main independent variables studied included the general severity score APACHE III, the revised trauma and injury severity scores (RTS, ISS), emergency treatment measures, the gas exchange index (PaO2/FIO2) recorded after the onset of ARDS and the development of multiple system organ failure (MSOF). Univariate and multivariate analyses were performed. Results: The mean age of patients was 42.1 +/- 16.7 years, 49 patients (83%) were male, the mean APACHE III score was 52.7 +/- 33.7 points, the ISS 28.5 +/- 11.4 points and the RTS 8.9 +/- 2.5 points. ICU length of stay was 28.5 +/- 24.5 days and the mortality rate 31.7% (19 deaths). Mortality was associated with the following: PaO2/FIO2 ratio on the 3rd, 5th and 7th days post-ARDS; high volume of crystalloid/colloid infusion during resuscitation; the APACHE III score; and the development of MSOF According to the multivariate analysis, the mortality of these patients was correlated with the PaO2/FIO2 ratio on the 3rd day of ARDS, the APACHE III score and the development of MSOF This analysis also showed days on mechanical ventilation to be the only variable that predicted ICU length of stay. Conclusions: The ICU mortality of trauma patients with ARDS is related to the APACHE III score, the gas exchange evolution as measured by the PaO2/FIO2 on the 3rd day and the progressive complications indicated by the onset of MSOF The length of ICU stay of these patients is related to the number of days on mechanical ventilation.