Background: We have previously shown that blood transfusion in the first 24 hours is an independent predictor of mortality, intensive care unit (ICU) admission, and increased ICU length of stay in the acute trauma setting when controlling for Injury Severity Score, Glasgow Coma Scale score, and age. Indices of shock such as base deficit, serum lactate level, and admission hemodynamic status (systolic blood pressure, heart rate) and admission hematocrit were considered potential confounding variables in that study. The objectives of this study were to evaluate admission anemia and blood transfusion within the first 24 hours as independent predictors of mortality, ICU admission, ICU length of stay (LOS), and hospital LOS, with serum lactate level, base deficit, and shock index (heart rate/systolic blood pressure) as covariates.
Methods: Prospective data were collected on 15,534 patients admitted to a Level I trauma center over a 3-year period (1998-2000) and stratified by age, gender, race, Glasgow Coma Scale score, and Injury Severity Score. Admission anemia and blood transfusion were assessed as independent predictors of mortality, ICU admission, ICU LOS, and hospital LOS by logistic regression analysis, with base deficit, serum lactate, and shock index as covariates.
Results: Blood transfusion was a strong independent predictor of mortality (odds ratio [OR], 2.83; 95% confidence interval [CI], 1.82-4.40; p < 0.001), ICU admission (OR, 3.27; 95% CI, 2.69-3.99; p < 0.001), ICU LOS (p < 0.001), and hospital LOS (Coef, 4.37; 95% CI, 2.79-5.94; p < 0.001) when stratified by indices of shock (base deficit, serum lactate, shock index, and anemia). Patients who underwent blood transfusion were almost three times more likely to die and greater than three times more likely to be admitted to the ICU. Admission anemia (hematocrit < 36%) was an independent predictor of ICU admission (p = 0.008), ICU LOS (p = 0.012), and hospital LOS (p < 0.001).
Conclusion: Blood transfusion is confirmed as an independent predictor of mortality, ICU admission, ICU LOS, and hospital LOS in trauma after controlling for severity of shock by admission base deficit, lactate, shock index, and anemia. The use of other hemoglobin-based oxygen-carrying resuscitation fluids (such as human or bovine hemoglobin substitutes) in the acute postinjury period warrants further investigation.