Therapeutic hypothermia? No benefit in cooling kids after in-hospital cardiac arrest (THAPCA)
Cooling kids to 33ºC after resuscitation from in-hospital cardiac arrest brought no benefits compared to fever prevention (maintenance at 36.8°C), in the large THAPCA randomized trial.
After one year, survival was 39% with hypothermia and 36% with management of body temperature in the normal range. There were no differences in neurologic outcomes or any other important clinical endpoint.
The trial was stopped early, partly because of slow enrollment, but mostly because of the very low statistical probability of a significant benefit from hypothermia emerging, based on the interim analysis. (They had postulated a whopping 15% absolute benefit in survival from therapeutic hypothermia.)
Results were reported at the Society of Critical Care Medicine conference and published in the New England Journal of Medicine.
Researchers at 37 children's hospitals randomized 329 patients to a normal temperature, or therapeutic hypothermia, which required pharmacologic paralysis and sedation, then a cooling blanket to maintain a target body temperature of 33°C (91.4°F) for 48 hours. Rewarming was done over 16 hours to a target temperature of 36.8°C (98.24°F).
Patients randomized to normal temperature maintenance were targeted to a body temperature 36.8°C for 5 days, using the same cooling blanket product.
The primary outcome was survival at 12 months with a favorable neurobehavioral outcome (score ≥70 on the Vineland Adaptive Behavior Scales). Secondary outcomes were survival at 12 months and change in neurobehavioral function, determined by the difference between baseline and VABS scores.
There were no significant differences in survival or neurobehavioral function by VABS scores.
The results echoed its 2015 sister study in 295 children surviving out-of-hospital cardiac arrest: those cooled to 33ºC did no better than those kept at 36.8°C, after 1 year.
Hypothermia is not standard practice for children after cardiac arrest. Pediatric Advanced Life Support guidelines advise the avoidance of hyperthermia (fever), but do not strongly advise therapeutic hypothermia.
THAPCA is in concordance with the largest randomized trial on therapeutic hypothermia performed in adults, in which cooling to 33ºC did not improve outcomes compared to maintenance of temperature at 36ºC, after out-of-hospital cardiac arrest.
Therapeutic Hypothermia after In-Hospital Cardiac Arrest in Children. N Engl J Med. 2017 Jan 26;376(4):318-329
Therapeutic hypothermia after out-of-hospital cardiac arrest in children. N Engl J Med. 2015 May 14;372(20):1898-908.