Since neurological recovery is very unlikely after 30 minutes of normothermic cardiac arrest, CPR was terminated, when resuscitation remained unsuccessful after 23 minutes of CPR. After ROSC, animals were randomized either to normothermia (38��C) plus TIVA (NT), hypothermia (33��C) plus TIVA (HT), or hypothermia (33��C) combined with 2.0 Vol% end-tidal sevoflurane and 0.3 ��g/kg/h sufentanil (HT+SEV). Since hypothermia was shown to increase blood concentrations of propofol by about 30% [14], we reduced continuous infusion of propofol during hypothermia targeting bispectral index values below 60. Body core temperature was monitored continuously by the arterial catheter, and normothermic body temperature was maintained at 38.0��C with a heating blanket, since the physiological rectal temperature of pigs is supposed to be about 38��C [15]. Hypothermia was induced by 1,000 mL saline (4��C) and maintained by a cooling device (Icy catheter and CoolGard 3000; Alsius Corp, Irvine, CA, USA) that was introduced into the femoral vein. According to the landmark study by Bernard et al. [16] we used a target body temperature of 33��C for 12 hours. Thereafter, re-warming was initiated (0.5��C per hour). One hour after ROSC, FiO2 was reduced to 0.4. During the post-resuscitation period, animals received crystalloid infusions to keep central venous pressure above 8 mm Hg and mean arterial blood pressure above 50 mm Hg. If this first step failed, additional norepinephrine was administered to keep mean arterial blood pressure above 50 mm Hg. We further aimed at serum glucose levels less than 150 mg/dL by intermittent insulin bolus administration. Animals were killed by an overdose of sufentanil, propofol and potassium chloride 24 hours after ROSC. Tissue samples of the cerebral cortex were collected within 15 seconds following euthanasia via a craniotomy that was established before euthanasia, and then immediately snap-frozen in liquid nitrogen (stored at -80��C) to minimize time-dependent effects of cerebral ischemia following euthanasia on cytokine expression. Autopsy was routinely performed for documentation of potential injuries to the thoracic and abdominal cavity during CPR.Figure 1Experimental time line. Thirty pigs were subjected to cardiac arrest following left anterior descending (LAD) coronary artery ischemia. Ventricular fibrillation (VF) was electrically induced twenty minutes after LAD occlusion. After seven minutes of VF, …Hemodynamic data, including mean arterial blood pressure, heart rate, end-tidal carbon dioxide, and cardiac index were determined at baseline (BL), following ROSC, and 7 and 24 hours after ROSC, respectively.