Letter to the Editor:
We commend the authors for this challenging multicenter randomized study on the use of therapeutic hypothermia (TH) in comatose children after cardiac arrest.1 Indeed, 1355 patients were screened to eventually lead to 260 evaluations of the primary outcome, 1-year survival with a VABS-II score of ≥70.
Conclusions from this study, however, are hampered by its limited power. It was designed to detect an absolute survival difference of 15–20% assuming a survival rate of 15–35% in normothermic patients with a power of 85%; under these overly optimistic and unfounded conditions despite pertinent literature,2–4 only 276 patients were calculated to be needed. An absolute difference of 8%, however, still corresponding to >50% relative increase in neurologically acceptable survival, and a 0.14 p-value strongly suggest that the study was severely underpowered (42%) to rightfully reject the null-hypothesis under these conditions.
Therefore, it would be premature to conclude that withholding TH from pediatric patients does not make a difference in outcome. A >50% increased survival, though not significant due to suboptimal study design, points in a very different direction.
References:
- 1.Moler FW, Silverstein FS, Holubkov R, et al. Therapeutic Hypothermia after Out-of-Hospital Cardiac Arrest in Children. N Engl J Med. 2015. April 25. [DOI] [PMC free article] [PubMed]
- 2.Young KD, Gausche-Hill M, McClung CD, Lewis RJ. A prospective, population-based study of the epidemiology and outcome of out-of-hospital pediatric cardiopulmonary arrest. Pediatrics 2004;114:157–64. [DOI] [PubMed] [Google Scholar]
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