Impact of a physician - critical care practitioner pre-hospital service in Wales on trauma survival: a retrospective analysis of linked registry data.

The Emergency Medical Retrieval and Transfer Service for Wales launched in 2015. This service delivers senior pre-hospital doctors and advanced critical care practitioners to the scene of time-critical life- and limb-threatening incidents to provide advanced decision-making and pre-hospital clinical care. The impact of the service on 30-day mortality was evaluated retrospectively using a data linkage system. The study included patients who sustained moderate-to-severe blunt traumatic injuries (injury severity score ≥ 9) between 27 April 2015 and 30 November 2018. The association between pre-hospital management by the Emergency Medical Retrieval and Transfer Service and 30-day mortality was assessed using multivariable logistic regression. In total, data from 4035 patients were analysed, of which 412 (10%) were treated by the Emergency Medical Retrieval and Transfer Service. A greater proportion of patients treated by the Emergency Medical Retrieval and Transfer Service had an injury severity score ≥ 16 and Glasgow coma scale ≤ 12 (288 (70%) vs. 1435 (40%) and 126 (31%) vs. 325 (9%), respectively). The unadjusted 30-day mortality rate was 11.7% for patients managed by the Emergency Medical Retrieval and Transfer Service compared with 9.6% for patients managed by standard pre-hospital care services. However, after adjustment for differences in case-mix, the 30-day mortality rate for patients treated by the Emergency Medical Retrieval and Transfer Service was 37% lower (adjusted odds ratio 0.63 (95%CI 0.41-0.97); p = 0.037). The introduction of an emergency medical retrieval service was associated with a reduction in 30-day mortality for patients with blunt traumatic injury.