National Database Study of the effect of mode of transportation on trauma patients injured in snowmobile accidents.

BACKGROUND: Snowmobile accidents occur in areas that may be difficult to reach by ground Emergency Medical Services (GEMS) vehicles. Helicopter EMS (HEMS) can potentially be useful in these situations, but there are few available data assessing HEMS-associated survival improvement in patients injured in snowmobile accidents. This study evaluates the national trauma database (NTDB) to identify snowmobile-related injury cases to determine if HEMS transport was associated with improved outcome, and whether any improvement in outcome is associated with worse functional status as indicated by disposition destination.

METHODS: Using the American College of Surgeons National Trauma Data Bank (NTDB) for the years 2017-2022, snowmobile-related injury cases that were transported from the scene and in which transport mode (HEMS or GEMS) and survival status was known were assessed. Multivariable logistic regression (including use of Mahalanobis metrics within propensity-score calipers) was used to evaluate the primary endpoint of survival, with effect estimates reported as adjusted odds ratio (OR) with 95% confidence interval (CI). A secondary endpoint "unfavorable disposition destination" was assessed in survivors, to determine whether any HEMS-associated survival improvement came at the cost of a worse functional outcome.

RESULTS: The study assessed 10,541 cases in which there were 521 (4.9%) deaths. Classical logistic regression incorporating demographics, vital signs, and receiving hospital characteristics indicated HEMS-associated improvement in survival (OR 1.9, 95% CI 1.4-2.7), which was confirmed in propensity-scored modeling indicating absolute risk difference of 2.7% (number needed to transport by HEMS to save one additional life: 37 with 95% CI 24-83). Secondary endpoint analysis did not suggest that improved HEMS survival came at cost of functional outcome; HEMS cases were slightly less likely to have unfavorable disposition destinations but the difference was not significant (OR 0.9, 95% CI 0.7-1.2, p = .461).

CONCLUSION: In a group of cases injured using snowmobiles, HEMS transport is associated with significantly improved mortality without any indication that improved survival comes at a cost of worse functional outcome.