What is the status of targeted temperature management (TTM)?
The 2010 American Heart Association Guidelines for Cardiopulmonary Resuscitation and Emergency Cardiovascular Care recommend that comatose (i.e., lack of meaningful response to verbal commands) adult patients with return of spontaneous circulation (ROSC) after out-of-hospital ventricular fibrillation cardiac arrest be cooled to 32 to 34° C (89.6 to 93.2° F) for 12 to 24 hours. Induced hypothermia also may be considered for comatose adult patients with ROSC after in-hospital cardiac arrest of any initial rhythm or after out-of-hospital cardiac arrest with an initial rhythm of pulseless electric activity or asystole.
Active rewarming should be avoided in comatose patients who spontaneously develop a mild degree of hypothermia (>32° C [89.6° F]) after resuscitation from cardiac arrest during the first 48 hours after ROSC.
The TTM after a cardiac arrest clinical trial published in 2013 included patients with both shockable and nonshockable rhythms experiencing out-of-hospital cardiac arrest.
The TTM trial showed that hypothermia at a targeted temperature of 33° C did not confer a benefit as compared with a targeted temperature of 36° C in the first 24 hours and both groups did not differ in complication rates.
It is left at the discretion of the hospital policy to use either 36 or 33° C pending further guidance.
It is important to highlight that 36° C in this trial was not intended to represent the normothermia arm but rather the TTM arm.
Maintaining this temperature target still requires similar active interventions as the induced hypothermia protocol.
