From the Guidelines
The targeted temperature range for post-cardiac arrest care is 32-36°C, maintained for at least 24 hours, as recommended by the most recent guidelines 1. This approach, known as targeted temperature management (TTM), should be initiated as soon as possible after return of spontaneous circulation in comatose patients. Implementation involves cooling with external cooling devices (cooling blankets, ice packs) or internal methods (cold saline infusion, endovascular catheters). Core temperature should be continuously monitored via esophageal, bladder, or pulmonary artery catheters. Patients typically require sedation (propofol 5-50 mcg/kg/min or midazolam 0.02-0.1 mg/kg/hr) and often neuromuscular blockade (cisatracurium 0.15 mg/kg bolus followed by 1-2 mcg/kg/min infusion) to prevent shivering. After the maintenance period, rewarming should occur slowly at 0.25-0.5°C per hour to avoid complications. TTM works by reducing cerebral metabolism, decreasing free radical production, and limiting reperfusion injury, thereby protecting the brain from secondary injury following cardiac arrest. Fever should be actively prevented for at least 72 hours post-arrest, even after the TTM period, as suggested by the latest consensus 1. Some key points to consider include:
- The use of a temperature control device with a feedback system based on continuous temperature monitoring to maintain the target temperature 1
- The prevention of fever by targeting a temperature ≤37.5° C for patients who remain comatose after ROSC from cardiac arrest 1
- The avoidance of routine use of prehospital cooling with rapid infusion of large volumes of cold intravenous fluid immediately after ROSC 1
- The suggestion to use surface or endovascular temperature control techniques when temperature control is used in comatose patients after ROSC 1 It is essential to follow the most recent guidelines and consensus statements, such as those from 2022 1, to ensure the best possible outcomes for patients.
From the Research
Targeted Temperature Range Post Arrest
- The recommended targeted temperature range for post cardiac arrest patients is between 32 °C and 36 °C for at least 24 hours 2.
- This temperature range is recommended for adults with out-of-hospital cardiac arrest with an initial shockable rhythm, as well as for those with nonshockable rhythms and in-hospital cardiac arrest 2.
- A study published in 2021 found that adherence to the recommended targeted temperature range decreased significantly after the publication of the TTM trial, but this did not result in a statistically significant difference in survival 3.
Ideal Timing and Duration of Targeted Temperature Management
- The ideal timing of targeted temperature management is not well established, but it is recommended to start as soon as possible after cardiac arrest 2.
- The duration of targeted temperature management is recommended to be at least 24 hours, and possibly up to 72 hours to prevent rebound hyperthermia 2, 4.
Sedation and Analgesia During Targeted Temperature Management
- Sedation and analgesia are commonly used during targeted temperature management, but there is great variability in the protocols used 5.
- A study published in 2018 found that sedation with propofol-remifentanil was associated with earlier awakening and more ventilator-free days compared to midazolam-fentanyl 6.