What is the target temperature range for post cardiac arrest patients?

Target Temperature Management in Post-Cardiac Arrest Patients

For comatose adult patients with return of spontaneous circulation (ROSC) after cardiac arrest, the recommended target temperature range is 32°C to 36°C, maintained for at least 24 hours after achieving target temperature. 1, 2

Patient Selection

• All comatose (lack of meaningful response to verbal commands) adult patients with ROSC after cardiac arrest should receive targeted temperature management (TTM)
  • Strong recommendation for ventricular fibrillation/pulseless ventricular tachycardia (VF/pVT) out-of-hospital cardiac arrest (OHCA) 1
  • Strong recommendation for non-shockable rhythms and in-hospital cardiac arrest 1

Temperature Selection Within the Range

When selecting a specific temperature within the 32-36°C range:

• Higher temperatures (36°C) may be preferred for patients with:

  • Bleeding risk 1, 2
  • Coagulopathy concerns

• Lower temperatures (32-34°C) may be preferred for patients with:

  • Seizures 1, 2
  • Cerebral edema 1, 2

• Consider the patient's initial temperature:

  • If presenting at the lower end of range, maintain at that temperature
  • If presenting at higher end, maintain at 36°C 1

Implementation Protocol

1. Induction phase:

   • Do NOT use prehospital cooling with rapid infusion of large volumes of cold IV fluid (Class III: No Benefit) 1, 2
   • This increases risk of re-arrest and pulmonary edema 1, 2

2. Maintenance phase:

   • Use temperature control devices with feedback systems based on continuous temperature monitoring 1, 2
   • Options include:
     • Water or air circulating blankets/pads
     • Intravascular heat exchangers
     • Surface cooling devices 1

3. Duration:

   • Maintain target temperature for at least 24 hours 1, 2
   • Even if target temperature isn't achieved, attempt temperature control for at least 24 hours 1

4. Rewarming phase:

   • Perform controlled rewarming at 0.25-0.5°C per hour 1, 2
   • Avoid rapid rewarming which may worsen neurological outcomes

5. Fever prevention:

   • After TTM, actively prevent fever (temperature >37.5°C) for 36-72 hours in patients who remain comatose 1, 2
   • Rebound hyperthermia is associated with increased mortality and worse neurological outcomes 1

Monitoring and Complications

During TTM, monitor for and manage:

• Bradycardia (may be beneficial and associated with good outcomes) 2
• Electrolyte disturbances
• Increased vasopressor requirements (more common with lower temperatures) 2
• Seizures (occur in 12-22% of post-cardiac arrest comatose patients) 2

Prognostication Timing

• The earliest time for prognostication using clinical examination in patients treated with TTM is 72 hours after normothermia 1, 2
• Do not rely on clinical criteria alone before this time to estimate prognosis 2

Important Caveats

• No significant difference in survival or neurological outcomes has been demonstrated between TTM at 33°C versus 36°C in recent high-quality trials 2, 3
• Avoid actively or rapidly warming patients to higher temperatures within the range 1
• Allowing temperatures to rise above 36°C is not consistent with current TTM recommendations 1
• Hyperthermia (>37.5°C) should be actively prevented as it is associated with poor outcomes 1

TTM remains the only potentially neuroprotective intervention recommended for post-cardiac arrest care 4, and should be implemented promptly in all eligible patients to improve neurological outcomes.