Therapeutic hypothermia (TH) has been shown to be effective in improving outcomes in adults and neonates with hypoxic-ischemic encephalopathy. The theory is that TH can diminish the secondary injury by decreasing the brain’s metabolic demands, the amount of inflammation and lipid peroxidation, and the excitotoxicity that occurs with brain injuries. Because of these effects , as well as successful studies in animal models, attempts have been made to use TH to improve outcomes in patients who have sustained traumatic brain injury (TBI). However, clinical trials have not definitively shown any improvement in clinical outcomes. The design of the Cool Kids trial altered some of the parameters used in the previous phase 3 trials – specifically, starting the cooling process earlier and continuing it for longer – in hopes of bolstering outcomes.