Transfusion strategies and development of acute respiratory distress syndrome in combat casualty care

BACKGROUND: Damage-control resuscitation (DCR) has been advocated to reduce mortality in military and civilian settings. However, DCR and excessive crystalloid resuscitation may be associated with a higher incidence of acute respiratory distress syndrome (ARDS). We sought to examine the impact of resuscitation strategies on ARDS development in combat casualty care. METHODS: A retrospective review of Joint Theater Trauma Registry data on US combat casualties who received at least 1 U of blood product within the first 24 hours of care was performed, cross-referenced with the cohort receiving mechanical ventilation (n = 1,475). Massive transfusion (MT, ≥10 red blood cells [RBCs] and/or whole blood in 24 hours) and volume/ratios of plasma/RBC, platelet/RBC, and crystalloid/RBC (C/RBC, crystalloid liters/RBC units) were examined using bivariate/multivariate logistic regression and local regression analyses as ARDS risk factors, controlling for age, injury severity, admission systolic blood pressure, and Glasgow Coma Scale (GCS) score. RESULTS: ARDS was identified in 95 cases (6.4%). MT was required in 550 (37.3%) of the analysis cohort. ARDS was more common in MT (46 of 550, 8.4%) versus no-MT cohort (49 of 925, 5.3%), but mortality was not different (17.4% MT vs. 16.3% no-MT). ARDS patients received significantly increased crystalloid of blood product volumes. Increased crystalloid resuscitation (C/RBC ratio > 1.5) occurred in 479 (32.7%) of 1,464 patients. Unadjusted mortality was significantly increased in the cohort with C/RBC ratio of 1.5 or less compared with those with greater than 1.5 (19.1% vs. 6.3%, p < 0.0001), but no difference in ARDS (6.5% vs. 6.6%) was identified. Platelet/RBC ratio did not impact on ARDS. Increasing plasma (odds ratio, 1.07; p = 0.0062) and crystalloid (odds ratio, 1.04; p = 0.041) volumes were confirmed as independent ARDS risk factors. CONCLUSION: In modern combat casualty care, increased plasma and crystalloid infusion were identified as independent risk factors for ARDS. These findings support a practice of decreased plasma/crystalloid transfusion in trauma resuscitation once hemorrhage control is established to achieve the mortality benefit of DCR and ARDS prevention. LEVEL OF EVIDENCE: Epidemiologic and prognostic study, level IV.