Study Design

Study Design:

Patients Screened: 3,551
Patients Enrolled: 275
NYHA Class: III or IV 11%
Mean Follow Up: 6 months
Mean Patient Age: 49 to 67
Female: 23
Mean Ejection Fraction: N/A

Patient Populations:

Patients seen consecutively in the emergency department, in whom spontaneous circulation had been restored after cardiac arrest, were eligible for the study. The inclusion criteria were a witnessed cardiac arrest, ventricular fibrillation or a nonperfusing ventricular tachycardia as the initial cardiac rhythm, a presumed cardiac origin of the arrest, an age of 18-75 years, an estimated interval of 5-15 minutes from the patient’s collapse to the first attempt at resuscitation by emergency medical personnel, and an interval of no more than 60 minutes from collapse to restoration of spontaneous circulation.

Exclusions:

Patients were excluded if they met any of the following criteria: a tympanic membrane temperature below 30°C on admission, a comatose state before the cardiac arrest due to the administration of drugs that depress the central nervous system, pregnancy, response to verbal commands after the return of spontaneous circulation and before randomization, evidence of hypotension (mean arterial pressure <60 mm Hg) for more than 30 minutes after the return of spontaneous circulation and before randomization, evidence of hypoxemia (arterial oxygen saturation <85%) for more than 15 minutes after the return of spontaneous circulation and before randomization, a terminal illness that preceded the arrest, factors that made participation in follow-up unlikely, enrollment in another study, the occurrence of cardiac arrest after the arrival of emergency medical personnel, or a known pre-existing coagulopathy

Primary Endpoints:

A favorable neurologic outcome within six months after cardiac arrest

Secondary Endpoints:

Mortality within six months and the rate of complications within seven days

Drug/Procedures Used:

Patients who had been resuscitated after cardiac arrest from ventricular fibrillation were randomly assigned to undergo therapeutic hypothermia (target temperature, 32°C to 34°C, measured in the bladder) over a period of 24 hours or to receive standard treatment with normothermia. Therapeutic hypothermia was induced with the use of an external cooling device and ice packs were used if the temperature goal was not achieved.

Concomitant Medications:

All patients received standard intensive care according to a detailed protocol. Midazolam and fentanyl were used for sedation. To avoid shivering, paralysis was induced by the intravenous administration of pancuronium (0.1 mg per kilogram) every two hours, for a total of 32 hours.