Table 1.

Characteristics of the included trials

	Duration	Participants	Experimental intervention	Control intervention	Inclusion criteria	Exclusion criteria	Follow-up time	Patients screened (n)	Patients included (n)
Mori 2000 (abstract) [20]	Not reported	OHCA patients with GCS <8	MIH to 32–34 °C for 72 h, method of cooling not described, rewarming rate not reported	36 °C for 72 h, method of temperature control not described	OHCA and GCS <8	Not defined	1 month	Not reported	54
Hachimi-Idrissi 2001 [22]	6 months	Unconscious OHCA patients, cardiac cause of arrest, initial rhythm asystole of PEA	Helmet cooling to 34 °C, when temperature of 34 °C achieved or more than 4 h elapsed from start of cooling, passive rewarming for 8 h	Standard ICU care, acetaminophen if temperature over 38 °C	OHCA of cardiac origin asystole or PEA as initial rhythm, >18 years, temp >30 °C, GCS <7	Pregnancy, coagulopathy, CNS antidepressant medication before CA, cardiogenic shock (MAP <60), GCS ≥7	14 days	Not reported	30
HACA 2002 [7]	65 months	Unconscious CA patients, cardiac cause of arrest, initial rhythm VF or non-perfusing VT	Air cooling induced hypothermia to 33 °C for 24 h, passive rewarming for 8 h	Standard ICU care, no temperature control	Witnessed CA of cardiac origin, VF or non-perfusing VT as initial rhythm, 18–75 years, 5–15 min from arrest to CPR and <60 min to ROSC	<30 °C, coma because of drugs before CA, pregnancy, response to verbal command, MAP <60 for >30 min, hypoxemia >15 min, terminal illness, factors making follow-up unlikely, coagulopathy, other study, CA after arrival of medical personnel	6 months	3551	275
Bernard 2002 [6]	33 months	Unconscious OHCA patients, cardiac cause of arrest, initial rhythm VF or VT	Ice-pack induced hypothermia to 33 °C for 12 h (started prior to hospital admission), active rewarming for 6 h	Standard ICU care, no temperature control	OHCA with VF as initial rhythm, persistent coma	<18 years for men, <50 years for women, cardiogenic shock <90 SBP despite epinephrine, other causes of coma than CA, no available ICU bed	Hospital discharge	Not reported (84 eligible)	77
Laurent 2005 [21]	23 months	Unconscious OHCA patients, cardiac cause of arrest, initial rhythm VF or asystole	CVVH to 32–33 °C (CVVH for 8 h and surface cooling for 16 h), passive rewarming	CVVH maintaining 37 °C for 8 h, thereafter no temperature control	OHCA of cardiac origin, VF of asystole, 18–75 years, <10 min to start of CPR, <50 min to ROSC	Pregnancy, response to verbal command, terminal illness before CA	6 months	244	42
Nielsen 2013 [11]	27 months	OHCA patients with GCS <8	Ice-cold fluids, ice packs, and intravascular or surface temperature-management devices induced hypothermia to 33 °C for 28 h, gradual rewarming to 37 °C in hourly increments of 0.5 °C, <37.5 °C for unconscious patients until 72 hours after CA	Ice-cold fluids, ice packs, and intravascular or surface temperature-management devices induced hypothermia to 36 °C for 28 h, gradual rewarming to 37 °C in hourly increments of 0.5 °C, <37.5 °C for unconscious patients until 72 hours after CA	OHCA of cardiac origin, GCS <8, >18 years, >20 min of spontaneous circulation after resuscitation	An interval from the ROSC to screening >240 min, unwitnessed arrest with asystole as the initial rhythm, suspected or known acute intracranial haemorrhage or stroke, <30 °C	180 days	950	939

CA Cardiac arrest, CNS Central nervous system, CPR Cardiopulmonary resuscitation, CVVH Continuous veno-venous filtration, GCS Glasgow Coma Score, HACA Hypothermia After Cardiac Arrest, ICU Intensive care unit, MAP Mean arterial pressure, MIH Mild induced hypothermia, OHCA Out-of-hospital cardiac arrest, PEA Pulseless electrical activity, ROSC Return of spontaneous circulation, SBP Systolic blood pressure, VF Ventricular fibrillation, VT Ventricular tachycardia