Intra-Arrest Transport Versus Continued On-Scene Resuscitation in Traumatic Cardiac Arrest: A Nationwide Cohort Study Using Time-Dependent Propensity Score Sequential Matching

Background: Traumatic out-of-hospital cardiac arrest (TCA) has an extremely poor prognosis, with reported 30-day survival of approximately 5%. Although potentially reversible causes exist, the optimal prehospital strategy—continued on-scene resuscitation or transport during ongoing cardiopulmonary resuscitation (intra-arrest transport)—remains unclear, particularly when accounting for time-dependent confounding.<br><br>Methods: We conducted a retrospective nationwide cohort study using the All-Japan Utstein Registry (2021–2023). Adults (≥18 years) with TCA were included. Intra-arrest transport was defined as transport initiated before return of spontaneous circulation. To address resuscitation-time bias, time-dependent propensity score sequential matching was applied to compare intra-arrest transport with continued on-scene resuscitation. The primary outcome was 30-day survival, and the secondary outcome was favorable neurological outcome at 30 days (Cerebral Performance Category 1–2).<br><br>Findings: Among 7,198 patients with TCA, 7,085 (98·4%) underwent intra-arrest transport and 113 (1·6%) received on-scene resuscitation. After matching, 7,070 exposure–control pairs were analyzed. Thirty-day survival was observed in 69 patients (1·0%) in the intra-arrest transport group and 63 patients (0·9%) in the on-scene resuscitation group (risk difference [RD], −0·2%; 95% confidence interval [CI], −0·6 to 0·3). Favorable neurological outcome occurred in 12 (0·2%) and 18 (0·3%) patients, respectively (RD, −0·2%; 95% CI, −0·5 to 0·0).<br><br>Interpretation: Intra-arrest transport was not associated with improved 30-day survival compared with continued on-scene resuscitation after adjustment for time-dependent confounding. These findings suggest that system-level optimization of trauma care may be more important than transport strategy alone.