A population-based assessment of a provincial prehospital trauma triage protocol: Refining the role of interfacility transfers

INTRODUCTION: Transporting injured patients to an appropriate level of care remains a complex challenge. In our trauma system, paramedics are mostly limited to basic life support and perform field triage guided by an algorithm that considers the type of injury and the estimated transport time to a Level 1 Trauma Center (L1TC). This study evaluates the effect of this triage protocol by comparing patient mortality between those transported directly to a L1TC and those initially transferred from another facility. METHODS: This retrospective study queried a Canadian L1TC trauma registry, which included all adult trauma patients who were admitted or died in the emergency department, between 2016 and 2022. Isolated burns, hanging, isolated hip fractures, arrival ≥ 72 h post-injury, death within 2 h of arrival at L1TC, or direct ward admissions were excluded from the study. We used multivariable logistic regression to compare in-hospital mortality between direct transport and interfacility transfer cohorts. Sensitivity and subgroup analyses were performed to further aid in refining triage criteria. RESULTS: Of 9488 registry patients, 1645 were excluded, leaving 4702 direct transports and 3141 interfacility transfers. Transferred patients were younger (median 59 vs. 67 years, p < 0.001), more severely injured (44.1 % vs 31.1 % ISS>15, p < 0.001) and had longer times to definitive care (9.32 h vs 1.15 h, p < 0.001). Overall, interfacility transfer was associated with a decreased odds of in-hospital mortality [aOR 0.54 (95 % CI 0.42-0.69)]. However, in our sensitivity and subgroup analyses, interfacility transfer was associated with an increased odds of mortality [aOR 4.17 (95 % 1.02-17.1)] if time to definitive care was