To the Editor.

When any new therapy is proposed, it is important to monitor for adverse events. Mild systemic hypothermia to 35.5°C by head cooling in term infants with hypoxic ischemic encephalopathy has recently been reported to be safe, and a multinational study with the power to evaluate efficacy is planned.¹ We have continued pilot studies with lower systemic temperatures, aiming to keep the nasopharyngeal temperature below 34°C, which was a critical temperature for neuronal rescue after carotid artery occlusion in our studies in fetal sheep.² Hypothermia is associated with recognized electrocardiography changes including sinus bradycardia, prolonged PR interval, prolonged QT interval . . . [Full Text of this Article]