Researchers at the University of Ottawa Heart Institute (UOHI) comparing the effect of moderate versus mild therapeutic hypothermia in comatose survivors of out-of-hospital cardiac arrest conclude there is no significant difference on mortality and neurologic outcomes. Comatose survivors of out-of-hospital cardiac arrest continue to experience high rates of death and severe neurologic injury. Results of the Effect of Moderate vs Mild Therapeutic Hypothermia on Mortality and Neurologic Outcomes in Comatose Survivors of Out-of-Hospital Cardiac Arrest are published in the Journal of the American Medical Association.
“In this randomized clinical trial studying comatose survivors of out-of-hospital cardiac arrest, a target temperature of 31 °C did not significantly reduce the rate of death or poor neurologic outcome at 180 days compared with a target temperature of 34 °C,” writes Dr. Michel Lemay, an interventional cardiologist and director of the Regional STEMI Program at the UOHI, and principal investigator leading the CAPITAL CHILL trial.
To our knowledge, this study is the first randomized clinical to evaluate the benefits of therapeutic hypothermia with a target temperature below 32 °C. The current study adds to the spectrum of target temperature management, as it did not find any benefit of even further lowering temperatures to 31 °C.
There has been much controversy as to the value of hypothermia. Targeted hypothermia was the first neuroprotective intervention thought to improve outcomes in comatose survivors of out-of-hospital cardiac arrest. The uncertainty that has surrounded the optimal target temperature has stimulated two decades of research and has led to improvement in multiple facets of post-cardiac arrest care.
Leigh B. Morris
University of Ottawa Heart Institute