The IH-TTM trial is designed to determine whether survival with a favorable neurological outcome is improved by induced hypothermia at 33°C in comatose critically ill patients admitted after resuscitated in-hospital cardiac arrest (IHCA). Recent evidence suggests that targeted temperature management (TTM) at 33°C may provide no survival benefits compared to controlled normothermia in unselected patients with out-of-hospital cardiac arrest (OHCA). However, this evidence is relevant only to OHCA of presumed cardiac origin, chiefly witnessed and immediately followed by resuscitation efforts. Only scant data are available for cardiac arrest (CA) of other origins and for IHCA.

In a randomized clinical trial of patients with CA in an initial non-shockable rhythm, the subgroup with IHCA had significantly better outcomes when treated with TTM at 33°C versus controlled normothermia; nevertheless, the sample size was limited. Another randomized controlled trial done specifically in patients with IHCA failed to show benefits of TTM at 33°C compared to controlled normothermia but was underpowered. Thus, whether therapeutic hypothermia is indicated after IHCA remains unclear. IH-TTM will be the largest trial assessing TTM after IHCA.

Inclusion Criteria:

• IHCA (unwitnessed IHCA with initial asystole; these patients may still be eligible if visible or audible signs of life were witnessed within 10 minutes after IHCA (no-flow duration ≤10 minutes, in keeping with the non-inclusion criteria for HYPERION study).
• Sustained ROSC (Return Of Spontaneous Circulation) defined as signs of circulation for 20 minutes without chest compressions
• At least 1 mg of epinephrine
• Coma defined as an inability to obey verbal commands (Glasgow Coma Scale motor response <6 or Full Outline of UnResponsiveness (FOUR) score motor response <4) after sustained ROSC
• Eligible for intensive care without restrictions or limitations
• Inclusion within 90 minutes of ROSC
• Age 18 years or older
• Next of kin informed about the trial and having consented to participation of the patient in the trial (patients with coma are unable to consent). If no next of kin can be contacted during screening for the study, trial inclusion will be completed as an emergency procedure by the ICU physician, in compliance with Country of inclusion law.
• Healthcare costs covered by the French statutory healthcare insurance system

Exclusion Criteria:

• Temperature at admission <30°C
• Obvious or suspected pregnancy
• Intracranial bleeding
• Dependent on others for activities of daily living before hospitalization
• Patient under curators, guardianship or under protection of justice
• Correctional facility inmate
• Patient who does no speak French