The Impact of Fluid Resuscitation on Clinical Outcomes According to Transport Time in Out-of-Hospital Cardiac Arrest Patients

<b>Background/Objectives</b>: Current guidelines recommend fluid resuscitation only for out-of-hospital cardiac arrest (OHCA) patients with hypovolemia. This study aimed to determine whether intravenous (IV) fluid resuscitation improves survival outcomes of OHCA patients and how fluid resuscitation is influenced by the emergency medical service (EMS)-treated time interval (ETI), including scene time interval and transport time interval. <b>Methods</b>: EMS-treated OHCA adult patients with presumed cardiac etiology were enrolled between 2018 and 2019. The main exposure was IV fluid resuscitation by an EMS provider during transportation. The main outcomes were survival to discharge and neurological recovery. Multivariable logistic regression analysis calculated adjusted odd ratios (aORs). Interaction analysis between IV fluid resuscitation and ETI was also performed. <b>Results</b>: Of 29,228 eligible patients, 13,683 (46.8%) patients received IV fluid resuscitation. Patients receiving IV fluid resuscitation had a significantly higher likelihood of survival to discharge (aOR [95% confidence interval, CI]: 1.15 [1.01-1.32]). Considering the interaction effects between IV fluid resuscitation and ETI for survival to discharge, aOR (95% CI) was 1.20 (1.02-1.43) for patients with an ETI > 16 min and <30 min and 1.48 (1.09-2.01) for patients with an ETI of >31 min (<i>p</i> for interaction <0.01) compared to ETI < 15 min, used as a reference. <b>Conclusions</b>: IV fluid resuscitation improved survival to discharge in OHCA patients, and this benefit was maintained only with the ETI > 16 min.