The association between geospatial and temporal factors and pre-hospital response to major trauma: a retrospective cohort study in the North of England

Major trauma is a leading cause of premature death and disability worldwide, and many healthcare systems seek to improve outcomes following severe injury with provision of pre-hospital critical care. Much research has focussed on the efficacy of pre-hospital critical care and advanced pre-hospital interventions, but less is known about how the structure of pre-hospital critical care services may influence response to major trauma. This study assessed the association between likelihood of pre-hospital critical care response in major trauma and factors important in the planning and development of those services: geographic isolation, time of day, and tasking mechanism. A local trauma registry, supported with data from the Trauma Audit and Research Network alongside additional information regarding pre-hospital management, identified patients sustaining major trauma admitted to Major Trauma Centres in the North of England. Data was extracted on location and time of incident, mechanism of injury, on-scene times, and presence or absence of pre-hospital critical care team. An isochrone map was constructed for 30-minute intervals to regional Major Trauma Centres, defining geographic isolation. Univariate logistic regression compared likelihood of pre-hospital critical care response to that of conventional ambulance response for varying degrees of geographic isolation, day or night period, and mechanism of injury, and multiple linear regression assessed the association between geographic isolation, service response and on-scene time. 2619 incidents were included, with 23.3% attended by pre-hospital critical care teams. Compared to conventional ambulance services, pre-hospital critical care teams were more likely to respond major trauma in areas of greater geographic isolation (OR 1.42, 95% CI 1.30–1.55, p < 0.005). There were significant differences in the mechanism of injury attended and no significant difference in response by day or night period. Pre-hospital critical care team response and increasing geographic isolation was associated with longer on-scene times (p < 0.005). Pre-hospital critical care teams are more likely to respond to major trauma in areas of greater geographic isolation. Enhanced pre-hospital care may mitigate geographic inequalities when providing advanced interventions and transport of severely injured patients. There may be an unmet need for pre-hospital critical care response in areas close to major hospitals.