Therapeutic hypothermia, still “too cool to be true?”

Abstract

Therapeutic hypothermia, an intervention reducing core body temperature below 35 degrees Celsius, has gained popularity in the management of acute brain injury after a series of small clinical trials in patients following cardiac arrest, stroke and traumatic brain injury. This article reviews the evidence relating to therapeutic hypothermia as an intervention in acute injury.

Optimal Protective Hypothermia in Arrested Mammalian Hearts

“…The OPH was determined by sigmoid curves of V max and dP/dt max The treatment with a temperature lower than normal body temperature to reach p35°C on the core temperature is considered as hypothermia (Swinhar, 2005;Gibson and Andrews, 2013). The protective hypothermia would be below 35°C and above the cooling injury threshold (29°C) (Ning et al, 2008).…”

“…A previous study indicated that as the pig heart temperature decreased from 37°C to 35.5°C, only the HR decreased progressively (Ning et al, 2008), but DP, dP/dt max , and CO did not significantly change. Generally, a core temperature p35°C is considered as hypothermia (Papile, 2005;Gibson and Andrews, 2013). In the beating pig hearts in vivo, there existed a cooling injury threshold for contractility at 29°C (Ning et al, 2008), suggesting that an optimal hypothermia for myocardial protection should be q29°C.…”

“…Therefore, an OPH should be 29°C or higher. A core temperature p35°C is considered as hypothermia (Papile, 2005;Gibson and Andrews, 2013), and the OPH should also be lower than 35°C. Previously, we demonstrated that an OPH exists in the isolated rabbit hearts (Xu et al, 1996;Ning et al, 1998cNing et al, , 1999.…”

“…There are significant variations between regions and individual institutions (Stub et al, 2012). Many guidelines, such as International Liaison Committee on Resuscitation (ILCOR), Cardiopulmonary Resuscitation (CPR) Guideline, and European Resuscitation Council (ERC), have recommended therapeutic hypothermia for postcardiac arrest syndrome as a beneficial and effective treatment (International Liaison Committee on Resuscitation, 2006;Mancini, 2011;National Institute for Health and Clinical Excellence, 2011;Boyce et al, 2012;Bro-Jeppesen et al, 2012;Jahn et al, 2012;Nagao, 2012;Gibson and Andrews, 2013;Søreide et al, 2013;Vollroth et al, 2013). The survival depends on multiplicands, including guideline quality, the levels of education, local implementation, and so on (Zobel et al, 2012).…”

“…The survival depends on multiplicands, including guideline quality, the levels of education, local implementation, and so on (Zobel et al, 2012). Recently, 32-34°C has been commonly used as the target hypothermia (Don et al, 2009;Kupchik, 2009;Gibson and Andrews, 2013); 32-33°C (Vollroth et al, 2013), 32.5°C (Murtha et al, 2014), 32.5-33.5°C (Bro-Jeppesen et al, 2012), 33°C (Zobel et al, 2012), 34°C (Choi et al, 2013;Testori et al, 2013), and 33-36°C (Nielsen et al, 2013) are also used. The results are different.…”