Location of Injury and Other Factors Associated With Increased Survival Among Severely Injured Geriatric Trauma Patients

Background Patients with a Trauma Injury Severity Score (TRISS) < .5 are termed "unexpected survivors." There is scarce information published on this subset of geriatric patients whose survival is an anomaly. Methods This is a retrospective case-control study examining all geriatric patients (age >= 65) not expected to survive (TRISS<.5) in the Pennsylvania Trauma Outcome Study (PTOS) database from 2013 to 2017. Primary outcome was survival to discharge. We selected 10 clinically important variables for logistic regression analysis as possible factors that may improve survival. Results 1336 patients were included, 395 (29.6%) were unexpected survivors. Factors that improved survival odds are the following: Place of injury: street/highway (AOR:0.51; 95% CI: .36-.73, P < .001) and residential institution (AOR:0.46; 95% CI: .21-.98, P = .043); and presence of Benzodiazepines (AOR:0.49; 95% CI: .31-.77, P = .002) or ethanol (AOR:0.57; 95% CI: .34-.97, P = .040). Factors that decreased survival odds are the following: Hypotension (AOR: 8.59; 95% CI: 4.33-17.01, P < .001) and hypothermia (AOR: 1.58; 95% CI: 1.10-2.28, P = .014). Gender, race/ethnicity, blood transfusion in first 24 hours, shift of presentation to Emergency Department, place of injury (farm, industrial, recreational, or public building), use of Tetrahydrocannabinol, amphetamines or opioids, and level of trauma activation did not impact survival. Discussion Location of injury (street/highway and residential institution) and ethanol or benzodiazepine use led to a significant increased survival in severely injured geriatric patients. Hypotension and hypothermia led to decreased survival. Future studies should determine possible reasons these factors lead to survival (and identify additional factors) to focus efforts in these areas to improve outcomes in geriatric trauma.