ISS is not an appropriate tool to estimate overtriage.

Purpose: The aim of this work is to study a cohort of patients of ISS < 15 admitted to a TC, and to determine the number of patients that ultimately benefited from the skills and resources specific of a level 1 trauma center.

Methods: Retrospective study from a prospective cohort of patients admitted to TC (Beaujon Hospital, APHP) for suspected severe trauma from January 2011 to December 2017. The main outcome criterion was the use of surgery or interventional radiology within the first 24 h after admission of patients with ISS < 15. The secondary outcomes were stratified into severe (mortality, resuscitation care, length of stay in intensive care units) and non-severe criteria (mild head injury, hospital discharge or transfer within 24 h).

Results: Of 3035 patients admitted during the study period, 1409 with an ISS < 15 were included, corresponding to a theoretical overtriage rate of 46.4%. Among these, 611 patients (43.4%) underwent emergency intervention within the first 24 h (586 surgical interventions, 19 direct transfers to the operating theater and 6 acts of interventional radiology), 238 (16.9%) of patients presented with severe and 531 (38%) with non-severe outcome criteria.

Conclusion: This work demonstrates that in a cohort of patients classified as ISS < 15 admitted to a TC, a considerable amount of TC-specific resources are required, and patients present with severe outcome criteria despite being classified as overtriaged. These results suggest that triage of trauma patients should be based on resource use and clinical outcome rather than anatomic criteria.