Cardiac arrest with apnea and loss of palpable pulse (CA) in childhood is a tragic event that often results in death or poor neurologic outcome. Recently, 2 adult randomized clinical trials (RCT) reported the use of mild hypothermia to improve both neurological outcome and survival in comatose survivors after ventricular fibrillation (VF). Similarly, recent RCTs in newborns with hypoxic-ischemic encephalopathy (HIE) also reported improved neurologic outcome after therapeutic hypothermia. For pediatric patients, no RCTs have been conducted of therapeutic hypothermia after CA and there are reasons for caution before widespread use. For example, children commonly have respiratory etiologies leading to a hypoxic period then CA; adults in contrast usually have a primary cardiac arrhythmia leading to sudden CA. In addition, children rarely develop VF as the initial rhythm causing CA as occurs in adults. Newborns with HIE, on the other hand, represent a unique birth associated event. We have current support to obtain cohort pilot data for planning of a RCT to examine the efficacy of therapeutic hypothermia after pediatric CA. This study is presently being completed at 15 sites associated with the Pediatric Emergency Care Applied Research Network (PECARN). Preliminary sample size estimates indicate that it will be feasible to conduct a RCT in 3 years of enrollment. This R34 application seeks funding to develop multiple documents and other materials necessary to accompany a RO1 application for a multicenter RCT of hypothermia in children who have sustained a CA. We plan to finalize inclusion and exclusion criteria and the sample size requirement for a future RCT; then we will confirm the length of patient enrollment required to perform the study at the 15 PECARN sites and recruit additional centers if needed to complete the enrollment phase of the RCT in 3 years. Additionally, we will develop the necessary documents to accompany a RO1 RCT application including a detailed manual of procedures (MOP) for the entire project, clinical research forms including web based forms for data entry, intra-institutional agreements, IRB related forms, and other study documents and forms described in detail within this application. Completion of this project will prepare our network to conduct a RCT of hypothermia for pediatric CA, as well as other high priority therapeutic interventional studies, aimed at improving outcomes of children who have sustained cardiac arrest. [unreadable] [unreadable] [unreadable]