Therapeutic cooling in cardiac arrest of noncardiac origin

On the basis of previous published data, the Interliaison Committee on Resuscitation has advised that unconscious adults with spontaneous circulation after out-of-hospital cardiac arrest should be cooled to 33°C during 24 hours when the initial rhythm was ventricular fibrillation (VF) and the cause of the cardiac arrest is of cardiac origin. We postulate that other rhythms might beneficiate from cooling as well as cardiac arrest of noncardiac origin. We therefore started a prospective study, and we compare the effect of cooling on long-term outcome in patients resuscitated after cardiac arrest of noncardiac origin or having rhythms other than VF.

Twenty-eight patients were included, 14 of them were subjected to hypothermia after achieving return of spontaneous circulation (ROSC) (hypothermia group), the remaining other 14 patients were subjected to normothermia (normothermia group). The cause of cardiac arrest was near asphyxia after strangulation or secondary to choking. Other patients had asystole or pulseless electrical activity (PEA) at the first rhythm assessment.

The postresuscitation phase was similar in both groups. In the hypothermia group, the cooling was initiated either by surface or intravenous cooling. The patient was cooled to 33°C as soon as possible in the Emergency Department, and the temperature was maintained for 24 hours. The re-warming phase was slowly started 24 hours later by increasing the body temperature by 1°C each 4 hours. No difference in complications was observed in the both groups. Good neurological outcome was highly significant in the hypothermia group (Table 1).

Table 1

In conclusion, cooling seems to improve the neurological outcome after cardiac arrest even in rhythms other than VF and cardiac arrest of noncardiac origin. Surprisingly cooling also mitigates the brain damage associated with asphyxial cardiac arrest in humans.