Prehospital advanced versus basic life support: A cohort study comparing survival to hospital for major trauma patients in New Zealand.

Objective: To examine the relationship between prehospital Advanced Life Support (ALS) and survival to hospital for major trauma patients in New Zealand and explore its implications for Emergency Medical Service (EMS) practice.

Methods: A mixed-methods explanatory design was used. Data on major trauma patients attended by road EMS (December 2016-November 2018) was analysed. A multivariable model with propensity scores estimated the odds of survival for patients receiving Advanced versus Basic Life Support (BLS). Semi-structured interviews conducted with EMS stakeholders were analysed using thematic analysis.

Results: Among 1118 patients, 661 (59 %) received ALS. Only 52 (5 %) did not survive to hospital. Multivariable modeling estimated ALS recipients had 1.5 times higher odds of survival than BLS-only recipients (OR 1.49, 95 % CI 0.66-3.35). Interviews with five EMS clinical leaders highlighted two likely influences: clinical judgment and evidence use. Despite imprecise quantitative findings, stakeholders supported ALS based on clinical judgment.

Conclusions: A tension between population-level results and provision of care based on clinical judgement exists. Quantitative analysis found no evidence that ALS offers a survival benefit, although considerable uncertainty exists, whereas stakeholders perceive ALS has clinical and equity benefits. Future research should assess equity, disability, and quality of life outcomes of ALS.