What is the targeted temperature range post cardiac arrest?

From the Guidelines

The recommended targeted temperature range for post-cardiac arrest patients is between 32°C and 36°C, as this range has been shown to improve outcomes in terms of morbidity, mortality, and quality of life 1.

Key Considerations

• The temperature range of 32°C to 36°C is recommended for patients in whom temperature control is used, with the goal of maintaining a constant target temperature within this range 1.
• Targeted temperature management (TTM) is recommended for adults with out-of-hospital cardiac arrest (OHCA) with an initial shockable rhythm who remain unresponsive after return of spontaneous circulation (ROSC) 1.
• The duration of TTM should be at least 24 hours, although the optimal duration is not well established 1.
• Prevention and treatment of fever in persistently comatose adults after completion of TTM is also suggested, as fever can worsen outcomes 1.

Implementation

• Cooling can be achieved using external methods such as ice packs, cooling blankets, or cold saline infusion, or internal methods such as endovascular cooling catheters.
• Core temperature should be monitored continuously via esophageal, bladder, or pulmonary artery catheter.
• Shivering should be prevented with sedation and analgesia, and neuromuscular blockade may be needed in some cases.
• After the maintenance period, rewarming should be done slowly at 0.25-0.5°C per hour to prevent complications.

Rationale

• The recommended temperature range is based on the strongest and most recent evidence, which suggests that TTM can improve outcomes by reducing metabolic demands, decreasing intracranial pressure, and mitigating reperfusion injury 1.
• The optimal temperature within the recommended range is not well established, and further research is needed to determine the best target temperature for specific patient populations 1.

From the Research

Targeted Temperature Range Post Cardiac Arrest

• The optimal targeted temperature range for post cardiac arrest patients is between 32 °C and 36 °C 2, 3, 4, 5.
• A study published in 2016 recommends targeted temperature management for adults with out-of-hospital cardiac arrest with an initial shockable rhythm at a constant temperature between 32 °C and 36 °C for at least 24 hours 2.
• Another study published in 2023 suggests that current guidelines recommend selecting and maintaining a constant target temperature between 32 and 36 °C for those patients in whom targeted temperature management is used 3.
• A prospective study published in 2011 found that there were no significant differences in mortality and neurologic outcomes after each target temperature (32°C, 33°C, and 34°C) during therapeutic hypothermia with return of spontaneous circulation after out-of-hospital cardiac arrest 4.
• A cohort study published in 2020 found that targeted temperature management at 33 °C was associated with better survival than targeted temperature management at 36 °C among patients with the most severe post-cardiac arrest illness but without severe cerebral edema or malignant EEG 5.
• An observational propensity score-matched study published in 2021 found that a multimodal sevoflurane-based sedation regimen in combination with targeted temperature management in post-cardiac arrest patients reduces the incidence of delirium 6.

Ideal Target Temperature

• The comparative benefit of lower (32-34 °C) versus higher (36 °C) temperatures remains unknown, and further research may help elucidate this 3.
• A study published in 2011 found that hypotension during the maintenance of therapeutic hypothermia significantly increased when the target temperature was 32°C, and recommended a target temperature of 33°C or 34°C rather than 32°C 4.
• A cohort study published in 2020 found that targeted temperature management at 33 °C was associated with better survival than targeted temperature management at 36 °C among patients with the most severe post-cardiac arrest illness but without severe cerebral edema or malignant EEG, while targeted temperature management at 36 °C was associated with better survival among patients with mild- to moderate-severity illness 5.