Neurological outcomes with hypothermia versus normothermia in patients with moderate initial illness severity following resuscitation from out-of-hospital cardiac arrest: protocol for a multicentre randomised controlled trial (R-CAST OHCA).

introductionTemperature control is a fundamental intervention for neuroprotection following resuscitation from cardiac arrest. However, evidence regarding the efficacy of hypothermia in post-cardiac arrest syndrome (PCAS) remains unclear. Retrospective studies suggest that the clinical effectiveness of hypothermia may depend on the severity of PCAS. The R-CAST OHCA trial aims to compare the efficacy of hypothermia versus normothermia in improving 30-day neurological outcomes in patients with moderately severe PCAS following out-of-hospital cardiac arrest. METHODS AND ANALYSIS: The multicentre, single-blind, parallel-group, superiority, randomised controlled trial (RCT) is conducted with the participation of 35 emergency and critical care centres and/or intensive care units at academic and non-academic hospitals. The study enrols moderately severe PCAS patients, defined as those with a revised post-Cardiac Arrest Syndrome for induced Therapeutic Hypothermia score of 5.5-15.5. A target number of 380 participants will be enrolled. Participants are randomised to undergo either hypothermia or normothermia within 3 hours after return of spontaneous circulation. Patients in the hypothermia group are cooled and maintained at 34°C until 28 hours post-randomisation, followed by rewarming to 37°C at a rate of 0.25°C/hour. Patients in the normothermia group are maintained at normothermia (36.5°C-37.7°C). Total periods of intervention, including the cooling, maintenance and rewarming phases, will occur 40 hours after randomisation. Other treatments for PCAS can be determined by the treating physicians. The primary outcome is a favourable neurological outcome, defined as Cerebral Performance Category 1 or 2 at 30 days after randomisation and compared using an intention-to-treat analysis. ETHICS AND DISSEMINATION: This study has been approved by the Okayama University Graduate School of Medicine, Dentistry and Pharmaceutical Sciences and Okayama University Hospital, Ethics Committee (approval number: R2201-001). Written informed consent is obtained from all participants or their authorised surrogates. Results will be disseminated via publications and presentations. TRIAL REGISTRATION NUMBER: jRCT1062220035.