Respiratory controversies in the critical care setting. Should all patients be treated with hypothermia following cardiac arrest?

Cardiac arrest is a common and lethal medical problem; each year more than half a million people in the United States and Canada suffer cardiac arrest treated by emergency medical personnel or in-hospital providers. Of those who survive to hospital admission or suffer in-hospital arrest, 40-60% die prior to discharge. Neurologic injury is the major source of morbidity and mortality after recovery of spontaneous circulation. Therapeutic options to prevent neurologic injury are limited, but recent randomized trials showed that moderate therapeutic hypothermia improves neurologic outcome in selected patients following cardiac arrest. Clear consensus statements recommend that unconscious adult patients with spontaneous circulation after out-of-hospital cardiac arrest should be cooled if the initial rhythm was ventricular fibrillation, and that therapeutic hypothermia should be considered for other patients (other rhythms or in-hospital arrest). However, the position that all patients should be cooled following cardiac arrest is probably too broad, given the lack of studies on patients with non-ventricular-fibrillation rhythms, in-hospital arrest, or non-cardiac causes of arrest. Further research is needed to determine the broadest application of moderate therapeutic hypothermia.