197 INCREASING NUMBER OF RIB FRACTURES PREDICTS MORTALITY IN MULTI-INJURY BLUNT TRAUMA VICTIMS

IntroductionRib fractures are common injuries in blunt trauma; however, their impact on patient mortality and morbidity may be underestimated. Recent evidence suggests that this may be especially true for older patients. In multiply injured patients with rib fractures, we hypothesized that the number of rib fractures independently predicts mortality and influences outcome.MethodsThe trauma registry of our Level I Trauma Center (1992-2004) was queried. The patient cohort consisted of blunt trauma victims that had one or more diagnosis codes associated with traumatic rib fractures as outlined by the International Classification of Diseases, 9th edition (ICD-9). The primary outcome was mortality. Potential predictors of mortality were screened including gender, age (≤ 65 years vs > 65 years), Injury Severity Score (ISS) (≤ 15 vs > 15), Glasgow Coma Score (GCS) (≤ 13 and > 13), number of ribs fractured, length of hospital stay, length of ICU stay, and discharge disposition. Student's t-test, one-way ANOVA, linear regression, and unadjusted logistic regression were used to screen potential predictors and only those statistically significant at the p < .05 level were included in the final models.ResultsA total of 1,033 patients sustained one to eight rib fractures from blunt trauma. Initial unadjusted analysis showed that age > 65 years, ISS > 15, and the number of ribs fractured were significantly associated with mortality (p < .05). Interestingly, ISS accounted for nearly all of the variability in hospital and ICU length of stay but not mortality. For mortality, multivariate logistic regression analysis demonstrated that ISS > 15 (OR 28, 95% CI 6, 120), age > 65 (OR 2.6, 95% CI 1.4, 5.1) and number of ribs fractured (OR 1.2, 95% CI 1.0, 1.3) were independent predictors of mortality. After adjusting for age and ISS, the risk of mortality increased 1.2 times for each rib fractured. Applying the Hosmer-Lemeshow goodness-of-fit statistic, the number of ribs fractured, ISS, and age accounted for 76% of the variability in mortality.ConclusionOur data indicate that ISS > 15, age > 65, and the number of rib fractures are independent predictors of mortality after blunt trauma. After adjusting for age and ISS, the number of ribs fractured was associated with an increased risk of mortality of 1.2 times the number of ribs fractured. Future management algorithms should incorporate specific guidelines to address the number of rib fractures in an effort to decrease mortality