Background Injury is a leading cause of death and health loss in New Zealand and internationally. The potentially fatal or severe consequences of many injuries can be reduced through an optimally structured prehospital trauma care system that can provide timely and appropriate care.

Objective To investigate the relationship between emergency medical services (EMS) care and survival to hospital for major trauma cases in New Zealand.

Methods This project is a retrospective cohort study of New Zealand major trauma cases attended by EMS providers over a 2-year period. Outcomes include survival to hospital and survival in hospital for at least 24 hours. The project has three phases: (1) identification of the cohort and assembling a bespoke longitudinal dataset linking EMS, New Zealand Major Trauma Registry and Coronial data; (2) describing the pathways and processes of care to inform an investigation of the relationships between types of EMS care and survival using propensity score modelling to adjust for case-mix differences; (3) assessment of the implications for future practice, policy and research.

Discussion The study findings will help identify opportunities to optimise the delivery of EMS care in New Zealand by informing the development or revision of existing major trauma EMS policies and guidelines, and to provide a baseline for monitoring the impact of future initiatives. Establishing an evidence-base will support a whole-of-system appraisal that could include broader complex variables relating to healthcare services throughout the continuum of trauma care.