A New Definition of Major Trauma

OBJECTIVE: This study aimed to compare the performance of Injury Severity Score (ISS)>15, High-Intensity Time-Sensitive (HITS) interventions (a surrogate for trauma team actions) or the combination to identify Major Trauma (MT). SUMMARY BACKGROUND DATA: MT is currently defined as ISS>15 although significant numbers of high-risk patients do not meet this definition. METHODS: Patients (18-89 yrs) from 2021-23 NTDB files were analyzed. Three MT definitions were evaluated: (1) ISS>15, (2) receiving a HITS intervention (HITS+), and (3) ISS>15 or HITS+, termed new Major Trauma (nMT+). The ability of each to identify deaths was evaluated using likelihood ratios and area under the receiver operating curves (AUROCs). RESULTS: Among 2,676,710 patients, 17.8% had ISS>15, 11.4% were HITS+, and 22.4% were nMT+: median age 58, 60% male, median ISS=9. 24-hour mortality was 7.6% for ISS>15, 11.5% for HITS+, and 7.4% for nMT+ (P<0.001). HITS had the highest positive likelihood ratio (6.70) for 24-hour mortality compared to ISS and nMT (4.29 and 4.12). nMT had the lowest negative likelihood ratio for 24-hour mortality (0.16), compared to ISS and HITS, (0.34 and 0.34). Compared to ISS>15 and HITS+, nMT+ exhibited significantly higher discriminatory power for predicting 24-hour mortality (AUROC: 0.83, 0.78, 0.79, P<0.001). In this cohort, nMT+ identified 19,851 (29%) more in-hospital deaths and 9138 (26%) more 24-hour deaths than either ISS>15 or HITS+ alone. CONCLUSIONS: The novel concept of nMT is a more comprehensive definition of major trauma than the existing ISS-based standard, providing the highest overall ability to discriminate survivors from non-survivors.