Changing epidemiology of trauma deaths leads to a bimodal distribution

Abstract

Injury mortality was classically described with a trimodal distribution, with immediate deaths at the scene, early deaths due to hemorrhage, and late deaths from organ failure. We hypothesized that the development of trauma systems has improved prehospital care, early resuscitation, and critical care and altered this pattern. This population-based study of all trauma deaths in an urban county with a mature trauma system reviewed data for 678 patients (median age, 33 years; 81% male; 43% gunshot, 20% motor vehicle crashes). Deaths were classified as immediate (scene), early (in hospital, ≤4 hours from injury), or late (>4 hours after injury). Multinomial regression was used to identify independent predictors of immediate and early versus late deaths, adjusted for age, gender, race, intention, mechanism, toxicology, and cause of death. Results showed 416 (61%) immediate, 199 (29%) early, and 63 (10%) late deaths. Compared with the classical description, the percentage of immediate deaths remained unchanged, and early deaths occurred much earlier (median 52 vs 120 minutes). However, unlike the classic trimodal distribution, the late peak was greatly diminished. Intentional injuries, alcohol intoxication, asphyxia, and injuries to the head and chest were independent predictors of immediate death. Alcohol intoxication and injuries to the chest were predictors of early death, while pelvic fractures and blunt assaults were associated with late deaths. In conclusion, trauma deaths now have a predominantly bimodal distribution. Near elimination of the late peak likely represents advancements in resuscitation and critical care that have reduced organ failure. Further reductions in mortality will likely come from prevention of intentional injuries and injuries associated with alcohol intoxication.

Figure 1

Mechanism of injury among 678 trauma deaths in Dallas County, 2005. GSW indicates gunshot wound; MVC, motor vehicle crash; MPC, motor vehicle vs pedestrian; MCC, motorcycle crash.

Figure 2

Primary cause of death. TBI indicates traumatic brain injury.

Figure 3

Timing of trauma deaths in the historical group from Trunkey's 1983 study (3) and in the group of 678 trauma deaths in Dallas County in 2005.

Figure 4

Timing distribution of trauma deaths compared with the historical trimodal distribution. The black line represents the historical trimodal distribution; bars represent the present study.

Figure 5

Time shift in early deaths in the group of 678 trauma deaths in Dallas County in 2005 compared with the historical group from Trunkey's 1983 study (3).