Therapeutic hypothermia has been successfully used to improve survival chances and reduce the risk of brain injury in adults after cardiac arrest and in newborn infants suffering from lack of oxygen but a large-scale study on the impact of body cooling in infants or children who have had cardiac arrest had not been done.
A new, randomized clinical study finds little neurological benefit to using therapeutic hypothermia to lower a child's core temperature after an out-of-hospital cardiac arrest.
The study is the first to compare the use of therapeutic hypothermia to active normothermia in pediatric patients. Active normothermia therapy maintains the body at normal temperature to prevent fever, which commonly occurs after cardiac arrest and can lead to more severe outcomes.
"We always felt that as important as hypothermia is, the avoidance of fever or hyperthermia, might actually be the key to improving outcome," said Charles Schleien, MD, co-author of the study and senior vice president and executive director of Pediatric Services for the North Shore-LIJ Health System, and chair of pediatrics at Cohen Children's Medical Center.
The study involved nearly 300 children between the ages of two days and up to 18 years old from the intensive care units of 38 leading children's hospitals in the United States and Canada. All had sustained an out-of-hospital cardiac arrest requiring chest compressions for at least two minutes, and who remained dependent on mechanical ventilation after circulation was returned.
Within six hours of return of circulation, patients were given either therapeutic hypothermia or normothermia therapy - treatments that control the body's core temperature for a period of time - in order to preserve brain function.
For the study, patients received one of the two treatments over a 120-hour timeframe. Those receiving therapeutic hypothermia had their body temperature lowered to 33°C (91.4°F) using sedation and cooling blankets for 48 hours and then rewarmed to36.8°C (98.24°F) for the remainder of the time period.
Children receiving normothermia therapy had their core temperature maintained at 36.8°C (98.24°F) for the entire time period.
The young patients were evaluated at the time of arrest (by parent questionnaire) and at four months and 12 months post arrest using the Vineland Adaptive Behavior Scale (VABS-II), which measures communication, daily living, motor and social skills.
Researchers found that there was no significant difference between the neurobehavioral outcomes of the two groups.
"Even though the hypothermic group did not improve outcome as defined by both mortality rate or severe brain disease after arrest, many of us still feel it's the avoidance of fever and actively maintaining normal temperature that may in fact be important as to why the outcomes in this study were not different," said Dr. Schleien, the lead New York area physician involved in the study, which ran from 2009 to 2013.
Presented at the Pediatric Academies Societies Annual Meeting in San Diego, CA.