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Neurology - Targeted Temperature Management - Fast Facts | NEJM Resident 360
Many organs are sensitive to the ischemia that occurs during cardiac arrest, especially the brain. Even after restoration of circulation, reperfusion and reoxygenation can cause further damage to the brain. Fewer than half of all patients that survive cardiac arrest have good neurologic recovery.
Targeted temperature management (TTM), reducing a patient’s body temperature to 32–34°C, is also known as therapeutic hypothermia, or cooling. This intervention is intended to limit neurologic injury after cardiac arrest. Initial studies found that treatment with hypothermia was associated with improved neurologic outcomes in patients with ventricular fibrillation (VF) and ventricular tachycardia (VT). Based on these studies, therapeutic hypothermia has been used widely in centers with the capability to do so, including in patients with pulseless electrical activity (PEA) and asystolic arrest who were not included in the initial studies. Hypothermia is postulated to suppress oxidative stress, apoptosis, and inflammation, as well as early hyperemia and delayed hypoperfusion. Cooling may have beneficial effects on other systems but is focused mainly on limiting neurologic injury.
Indications: The American Heart Association (AHA) and the European Resuscitation Council (ERC) recommend that comatose adult patients who experience return of spontaneous circulation (ROSC) after cardiac arrest should be treated with TTM and maintained at a constant temperature between 32°C and 36°C for at least 24 hours. However, the quality of evidence to support these recommendations is low, and as a result, recommendations may change as new evidence emerges.
Contraindications: There are few recognized contraindications to TTM. The ERC suggests that a higher temperature could be targeted in patients with severe cardiovascular impairment at 33°C.