The growing elderly population in the United States presents medical, engineering, and legislative challenges in trauma management and prevention. Thoracic injury incidence, morbidity, and mortality increase with age. This study utilized receiver-operator characteristic analysis to identify the quantitative age thresholds associated with increased mortality in common isolated types of thoracic injuries from motor vehicle crashes (MVCs).
The subject pool consisted of patients with a single AIS 3+ thorax injury and no injury greater than AIS 2 in any other body region. A logistic regression algorithm was performed for each injury to estimate an age threshold that maximally discriminates between survivors and fatalities. The c-index describing discrimination of the model and odds ratio describing the increased mortality risk associated with being older than the age threshold were computed.
Twelve leading thoracic injuries were included in the study: unilateral and bilateral pulmonary contusion (AIS 3/4), hemo/pneumothorax, rib fractures with and without hemo/pneumothorax (AIS 3/4), bilateral flail chest, and thoracic penetrating injury with hemo/pneumothorax. Results are consistent with the traditional age threshold of 55, but were injuryspecific. Pulmonary contusions had lower age thresholds compared to rib fractures. Higher severity pulmonary contusions and rib fractures had lower age thresholds compared to lower severity injuries.
This study presents the first quantitatively estimated mortality age thresholds for common isolated thoracic injuries. This data provides information on the ideal ‘threshold’ beyond which age becomes an important factor to patient survival. Results of the current study and future work could lead to improvements in automotive safety design and regulation, automated crash notification, and hospital treatment for the elderly.