Should children who have a cardiac arrest be treated with therapeutic hypothermia?

The International Liaison Committee for Resuscitation recommends that comatose adult patients with spontaneous circulation after cardiac arrest are cooled to 32-34°C for 12-24 hours based on analysis of data from two randomised controlled trials and 17 observational studies.1 However, these studies were mostly in a specific subgroup of cardiac arrest patients with witnessed, out-of-hospital ventricular fibrillation, and evidence of benefit in the general population of cardiac arrest patients has been less certain.2 The rationale for therapeutic hypothermia is that it can reduce cerebral metabolism, attenuate biosynthesis of excitotoxic compounds, reduce free radical production, reduce inflammation, and regulate gene and protein expressions associated with necrotic and apoptotic pathways during ischaemia and reperfusion.3

Recommendations for treatment in children4 (box 1) are based almost solely on adult data. However, the aetiology of cardiac arrest is very different in children,5 possibly altering the pattern of neuronal injury. Most cardiac arrests are secondary to a respiratory cause with profound hypoxia, and primary cardiac causes of arrests, including ventricular fibrillation, are rare. In other clinical situations, therapeutic hypothermia has been seen to be both beneficial (newborns with hypoxic brain injury within 6 hours of birth)6 and potentially harmful (traumatic brain injury).7 It is therefore important that the question of whether children with cardiac arrest should be treated with therapeutic hypothermia is addressed.