Causation and outcomes of diaphragmatic injuries in vehicular crashes.

BACKGROUND: This study aimed to identify vehicular and crash factors associated with diaphragmatic injuries (DIs). METHODS: DI presence was analyzed among Crash Injury Research and Engineering Network vehicular occupants (age >= 16 years) in relation to occupant and crash factors. Contact points (i.e., components in direct contact with occupants) involved in injury causation were analyzed. Cases with and without DI were compared in relation to mortality, Injury Severity Score (ISS) and the occurrence of injuries with a maximum Abbreviated Injury Scale (MAIS) score of 3+. Student's t test, Wilcoxon test, chi(2), and multiple logistic regression were used for statistical analysis. RESULTS: Of a total of 2,344 cases with complete data for analysis, 80 cases (3.4%) experienced DI. Multiple logistic regression analysis revealed a significant association with the occurrence of DI for near lateral impact (odds ratio, 7.71 [4.20-14.58]) and change in velocity (Delta V) of 40 km/h or greater (odds ratio 2.58 [1.29-5.24]). The seat belt and steering wheel were the most common contact points among frontal impact crashes, and the side interior surface and side hardware or armrest were the more common contact points among side impact crashes. DI cases experienced more MAIS3+ injuries in the head, chest and abdominal regions and exhibited higher median ISS (q1-q3) [42 (29-62.5) vs. 17 (10-27), p < 0.0001]. While mortality was higher among occupants with DI (48% vs. 14%), this effect disappeared when adjusted by ISS. CONCLUSION: DI are associated with lateral crashes and higher Delta V. Head, chest, and abdominal injuries occur more commonly among DI patients, and the presence of these injuries rather than the DI itself is responsible for the increased mortality in these patients. (J Trauma Acute Care Surg. 2013;74: 835-838. Copyright (c) 2013 by Lippincott Williams & Wilkins)