What is the effect of targeted temperature management (TTM) on out-of-hospital cardiac arrest survival?

Updated: Jul 26, 2019
  • Author: Alex Koyfman, MD; Chief Editor: Karlheinz Peter, MD, PhD  more...
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Answer

The incidence of out-of-hospital sudden cardiac arrest in industrial countries is reported to be between 35.7 and 128.3 cases per 100,000, with a mean of 62 cases per year. [6] This translates into approximately 300,000 people in the United States and about the same number in Europe each year. Despite nearly 40 years of prehospital advanced life support, the survival rate of out-of-hospital cardiac arrest is very poor. [7] Less than half of victims who develop return of spontaneous circulation (ROSC) survive to leave the hospital alive, and the cause of death is anoxic brain injury in most patients with ROSC who die within one month of the cardiac arrest. Inducing mild therapeutic hypothermia in selected patients surviving out-of-hospital sudden cardiac arrest has a major impact on long-term neurologically intact survival and may prove to be one of the most important clinical advancements in the science of resuscitation.

Some early great physicians, including Hippocrates, recognized the utility of hypothermia in attenuating injury. [8] The concept has experienced periodic reemergence in the medical literature, and recent studies of the modality date back mostly to the 1950s. In 1954, Hegnauer and D'Amato demonstrated decreased oxygen consumption in hypothermic dogs, [9]  and the study by Benson et al of hypothermia after cardiac arrest in humans [10] demonstrated decreased mortality.

Until relatively recently, evidence for targeted temperature management (TTM) has lacked sufficient weight and the advisory panel support that thereby follows to propel it into common practice. Despite its 2005 inclusion in American Heart Association (AHA) guidelines for cardiopulmonary resuscitation (CPR) and emergency cardiovascular care, and 2003 advisory statements by the International Liaison Committee on Resuscitation (ILCOR) and the European Resuscitation Council (ERC), TTM is largely misunderstood and inconsistently applied. [11, 12, 13]  The 2015 guidelines have modified the specific temperature range and duration of TTM on the basis of several more recent studies. [2]


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