Normothermia Shows Viability for Post Cardiac Arrest Temperature Management

Using either normothermia or hypothermia as temperature management strategies following cardiac arrest with spontaneous circulation recovery may produce similar patient outcomes with respect to death and severe disability, according to a science advisory from the American Heart Association (AHA) published in Circulation.

The AHA’s Emergency Cardiovascular Care Committee reviewed data from1861 eligible patients (79.4% men) from the Hypothermia Versus Normothermia After Out-of-Hospital Cardiac Arrest (TT2M; ClinicalTrials.gov Identifier: NCT02908308) clinical trial who spontaneously regained circulatory function following an out-of-hospital cardiac arrest. Study participants underwent random assignment to temperature management with hypothermia (target temperature, 33°C) or normothermia (target temperature, 37°C ) for 28 hours, followed by gradual rewarming to 37°C. A total of 46% of individuals managed with normothermia received active temperature management due to a core temperature that approached 37.5°C.

There was no significance difference in the primary outcome of death between individuals managed with hypothermia and participants measured with normothermia (50% vs 48%; P = .37), the report shows. Moderate to severe disability was not significantly different between the groups (55% for both), and hemodynamically compromising arrhythmias occurred more frequently among individuals managed with hypothermia compared with normothermia (24% vs 16%; P < .001). There were not significant differences between the 2 cohorts for other adverse events.

The writing group confirmed that for unresponsive patients who spontaneously regained circulation following cardiac arrest, maintaining patient temperature at 37.5°C or less is a reasonable and evidence-based strategy. However, the team was unable to determine whether hypothermia management offered any additional benefits compared with normothermia. “In the absence of a clear nonsurvivable catastrophic brain injury resulting from [out-of-hospital cardiac arrest], strictly preventing fever with continuous temperature monitoring, providing comprehensive critical care support, and deploying multimodal evidence-based strategies for neuroprognostication at a minimum of 72 hours after normothermia remain essential for unresponsive post–cardiac arrest adult patients,” according to the researchers.