Establishing thresholds for shock index in children to identify major trauma

•The shock index (SI) can be used to identify injured children with major trauma.•We used empirically-derived age-based Z-scores for SI to identify cutpoints maximally predictive of major trauma.•Compared to existing criteria, the empirically-derived SI cutoffs demonstrated a gain in sensitivity by approximately 10 %.•Further research is required to evaluate the potential role of incorporating these criteria into field and hospital trauma triage. An abnormal shock index (SI) is associated with greater injury severity among children with trauma. We sought to empirically-derive age-adjusted SI cutpoints associated with major trauma in children, and to compare the accuracy of these cutpoints to existing criteria for pediatric SI. We performed a retrospective cohort study using the 2021 National Trauma Data Bank (NTDB) Participant Use File. We included injured children (