(Vienna, 12 June 2023) Temporarily lowering the body temperature is considered a way to prevent or limit brain damage after resuscitation in the event of cardiac arrest. Researchers at MedUni Vienna's Department of Emergency Medicine have now analysed the results of several studies in a Cochrane Review and shown to what extent cooling methods can reduce the risk of brain damage and improve neurological outcomes after successful resuscitation.
Cardiac arrest is a life-threatening condition in which the heart stops beating and blood circulation throughout the body stops. Immediate resuscitation measures are crucial to save the life of the victim. This involves the use of various techniques such as chest compressions, ventilation techniques and the use of a defibrillator. After successful resuscitation, it is important to prevent or limit brain damage in order to preserve the function and structure of the nerve cells in the brain. Cooling the body to a temperature of 32°C to 34°C can be a therapeutic option to prevent cell damage.
The researchers at MedUni Vienna's Department of Emergency Medicine analysed twelve studies involving a total of 3956 people investigating the effects of cooling the body after successful resuscitation during cardiac arrest. The results showed that cooling may reduce the risk of brain damage and improve neurologic outcome. Out of 1000 people whose bodies were cooled, 532 had no or only minor brain damage, compared to only 377 out of 1000 people whose bodies were not cooled. Cooling had no effect on survival. The overall quality of the data is limited. However, a slightly increased risk of pneumonia and irregular heartbeats was observed in the cooled subjects.
Exploring optimal cooling methods
These new findings help to improve the understanding and treatment options for patients with cardiac arrest and successful resuscitation. However, the authors stress that further research is needed to investigate optimal cooling strategies. "Our review suggests that it may be useful to cool the body down after resuscitation in cardiac arrest, even when this intervention is discussed controversially by international experts. A rapid onset of cooling may be critical for an optimal effect. Our results also suggest that the type of cardiac arrest, e.g. how long it took to resuscitate, may determine whether and how patients benefit from cooling. Assessing a possible dose-response relationship of therapeutic hypothermia, i.e. how long or to which target temperature cooling should be applied, could determine the optimal treatment regimen, which is why we urgently need more clinical trials with good design, early application of the therapy and high quality," first author Jasmin Arrich comments on the results. Jasmin Arrich is a member of the Editorial Board of Cochrane Emergency & Critical Care (Denmark). Harald Herkner leads Cochrane Emergency & Critical Care as Co-ordinating Editor. Both work at the Department of Emergency Medicine at MedUni Vienna.
Publication: Cochrane Database of Systematic Reviews
Hypothermia for neuroprotection in adults after cardiac arrest; Jasmin Arrich, Nikola Schütz, Julia Oppenauer, Janne Vendt, Michael Holzer, Christof Havel, Harald Herkner; https://doi.org/10.1002/14651858.CD004128.pub5