Functional outcomes of motor vehicle crash thoracic injuries in pediatric and adult occupants

Abstract

Objective: Characterization of the severity of injury should account for both mortality and disability. The objective of this study was to develop a disability metric for thoracic injuries in motor vehicle crashes (MVCs) and compare the functional outcomes between the pediatric and adult populations.

Methods: Disability risk (DR) was quantified using Functional Independence Measure (FIM) scores within the National Trauma Data Bank for the most frequently occurring Abbreviated Injury Scale (AIS) 2-5 thoracic injuries. Occupants with thoracic injury were classified as disabled or not disabled based on the FIM scale, and comparisons were made between the following age groups: pediatric, adult, middle-aged, and older occupants (ages 7-18, 19-45, 46-65, and 66+, respectively). For each age group, DR was calculated by dividing the number of patients who were disabled and sustained a given injury by the number of patients who sustained a given injury. To account for the effect of higher severity co-injuries, a maximum AIS adjusted DR (DR_MAIS) was also calculated for each injury. DR and DR_MAIS could range from 0 to 100% disability risk.

Results: The mean DR_MAIS for MVC thoracic injuries was 20% for pediatric occupants, 22% for adults, 29% for middle-aged adults, and 43% for older adults. Older adults possessed higher DR_MAIS values for diaphragm laceration/rupture, heart laceration, hemo/pneumothorax, lung contusion/laceration, and rib and sternum fracture compared to the other age groups. The pediatric population possessed a higher DR_MAIS value for flail chest compared to the other age groups.

Conclusion: Older adults had significantly greater overall disability than each of the other age groups for thoracic injuries. The developed disability metrics are important in quantifying the significant burden of injuries and loss of quality life years. Such metrics can be used to better characterize severity of injury and further the understanding of age-related differences in injury outcomes, which can influence future age-specific modifications to AIS.

Keywords: Disability; elderly; functional outcome; motor vehicle crash; pediatric trauma; thoracic injuries.

Figure 1.

MAIS-adjusted disability risk (DR_MAIS) vs MAIS-adjusted mortality risk (MR_MAIS) for the top 95% list AIS 2, 3, 4, and 5 thoracic injuries by age group

Figure 2.

MAIS-adjusted disability risk (DR_MAIS) vs AIS severity for the top 95% list AIS 2, 3, 4, and 5 thoracic injuries by age group.

Figure 3.

DR_MAIS for AIS 2, 3, 4, and 5 thoracic injuries for pediatric patients versus adults (top), middle-aged (middle), and older adults (bottom). DR_MAIS for each injury in the pediatric group is plotted against the DR_MAIS of that injury for the adult age groups. Injuries are categorized by AIS severity as noted in the legend. Injuries are also categorized by injury groupings as designated by color of marker. Injuries appearing above the equivalency line demonstrate a greater DR_MAIS for pediatric patients than for the given adult age group.