From the Guidelines
The current recommendation for target temperature management (TTM) in cardiac arrest patients is to maintain a temperature between 32-36°C for at least 24 hours in comatose adult patients after return of spontaneous circulation (ROSC) 1. This approach is based on the latest evidence from the 2020 international consensus on cardiopulmonary resuscitation and emergency cardiovascular care science with treatment recommendations, which suggests that TTM can be beneficial for patients with out-of-hospital cardiac arrest (OHCA) and in-hospital cardiac arrest (IHCA) with an initial nonshockable rhythm 1. The HYPERION trial, a French trial published in 2020, found that TTM with a target temperature of 33°C improved outcomes compared to normothermia in comatose patients with OHCA and IHCA with an initial nonshockable rhythm 1. Key aspects of TTM implementation include:
- Rapid cooling using external or internal cooling devices
- Continuous temperature monitoring via esophageal, bladder, or intravascular probes
- Sedation and sometimes neuromuscular blockade to prevent shivering
- Gradual rewarming at 0.25-0.5°C per hour to avoid rebound hyperthermia
- Fever prevention (keeping temperature ≤37.5°C) for at least 72 hours after ROSC in all post-cardiac arrest patients TTM works by reducing cerebral metabolism, decreasing free radical production, and limiting reperfusion injury, thereby protecting the brain during the critical post-arrest period 1. Potential complications of TTM include coagulopathy, increased infection risk, and electrolyte disturbances, requiring close monitoring of potassium, magnesium, and glucose levels throughout treatment. It is essential to note that the optimal duration for TTM is unknown, but current guidelines suggest a minimum of 24 hours 1. Additionally, the choice of target temperature within the 32-36°C range may depend on individual patient factors, and further research is needed to determine the most effective temperature for specific subpopulations of cardiac arrest patients 1.
From the Research
Target Temperature Management in Cardiac Arrest Patients
- The latest research on target temperature management in cardiac arrest patients suggests that it is recommended 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.
- A recent randomized trial reported similar outcomes in patients treated with targeted temperature management at either 33 °C or 36 °C 2.
- The International Liaison Committee on Resuscitation Advanced Life Support Task Force recommends against prehospital cooling with rapid infusion of large volumes of cold intravenous fluid 2.
- Fever management with or without a temperature control device after out-of-hospital cardiac arrest is being investigated in a randomized clinical trial, with the goal of determining if post-cardiac arrest management of fever with or without a temperature control device affects patient-important outcomes after cardiac arrest 3.
Sedation and Temperature Management
- Midazolam for post-arrest sedation in pre-hospital emergency care has been shown to lead to more frequent pre-hospital attainment of the oxygenation and ventilation targets in post-resuscitation care, without any evidence of an elevated risk of hemodynamic complications 4.
- A retrospective comparison of ketamine-based and midazolam-based induction protocols for prehospital emergency anaesthesia in patients with return of spontaneous circulation following medical cardiac arrest found no demonstrable difference in post-induction hypotension between the two groups 5.
Time to Treatment and Return of Spontaneous Circulation
- The effect of time to treatment with antiarrhythmic drugs on return of spontaneous circulation in shock-refractory out-of-hospital cardiac arrest has been investigated, with results showing that the probability of return of spontaneous circulation decreases as time to drug administration increases 6.
- The effect of amiodarone, but not lidocaine, to restore return of spontaneous circulation declines with longer times to drug administration, potentially attributable to its adverse hemodynamic effects 6.