Interaction effect between prehospital hydration and initial cardiac rhythm in traumatic out-of-hospital cardiac arrest: a nationwide observational study

Traumatic cardiac arrest (TCA) is different in etiology compared to medical cardiac arrest. In case of TCA, it is important to initiate early fluid resuscitation. Initial cardiac rhythm serves as an indicator of outcomes in case of cardiac arrest. We aimed to find the association between prehospital hydration and outcomes of TCA according to initial cardiac rhythm. This is a retrospective, observational, crosssectional study. An examination was undertaken involving patients afflicted with TCA within the timeframe of 2014 to 2019. Exposure was defined to encompass prehospital hydration; interactive exposure was categorized by initial cardiac rhythm (non -shockable vs. shockable); the primary outcome was defined as good neurological status at discharge, whereas the secondary outcome was defined as survival to discharge. Multivariable logistic regression analysis was used to calculate adjusted odds ratios (AORs) with 95% confidence intervals (CIs). A comprehensive analysis was conducted on a cumulative of 20,247 patients. Rates of good neurological status and survival to discharge were 0.2% and 8.3% (non -shockable rhythm group) and 3.0% and 16.7% (shockable rhythm group), respectively. However, rates of good neurological status and survival to discharge were 0.2% and 7.9% (non-prehospital hydration group) and 0.3% and 10.0% (hydration group), respectively. Compared to the non -hydration group, the AORs for good neurological status at discharge was 1.44 (95% CI: 0.77-2.69) for the hydration group. Moreover, compared to the non -shockable rhythm group, the AORs for good neurological status at discharge was 19.74 (95% CI: 10.46-27.26) in the shockable rhythm group. The interaction analysis conducted between prehospital hydration and initial rhythm unveiled the efficacy of prehospital hydration in promoting favorable survival to discharge outcomes in the non -shockable rhythm group. Therefore, prehospital hydration is recommended for those with TCA characterized by a nonshockable rhythm before transport from the incident location.