Background Since April 2015 EMRTS provides pre hospital, consultant-led, critical care for people in Wales with life or limb threatening injuries or illness. Consultants and critical care practitioners on air ambulances and 4 × 4 emergency response vehicles now deliver emergency department equivalent; time critical; lifesaving treatment on scene and during transfer to hospital. This service covers 95% of the population by air and 46% by road within 30 minutes and aims to improve patient survival and outcomes.

Methods Multi-sourced linked datasets are being used in evaluation, including mortality, hospital admission, ED, on scene clinical electronic reporting forms that include incident details, vital signs, and treatments/procedures. Patients will be interviewed six months and one-year post incident for longer-term functional and quality of life outcomes. Data will be anonymized and made available for research and evaluation through the Secure Anonymised Information Linkage (SAIL) facility. WAST (Welsh Ambulance Service Trust) will also provide data to incident to scene and care times. Cases from both pre-EMRTS historical data and EMRTS-offline (restricted flying night/bad weather) will be used as comparators in the evaluation.

Results Data are being assembled for evaluation. The pattern of missions has changed following EMRTS; injury related attendances decreased from 56% to 51% and cardiac/respiratory deployments increased from 9% to 20%. Median response to arrival at scene times are unchanged (15 mins) but arrival at scene to hospital increased from 45 to 64 minutes. Further results on outcomes will be presented.

Conclusions Evaluation is just beginning and will include comparison of survival, resource use and health related quality of life with local and international data.