Preventing hypothermia in pediatric neurosurgery in Africa—A randomized controlled non‐inferiority trial of insulation versus active warming

Abstract

AbstractPurposeThe objective of this study was to compare the efficacy of a low‐cost heat‐preserving method in preventing intraoperative hypothermia with that of forced‐air warming in a resource‐limited setting.MethodsIn this randomized controlled non‐inferiority trial, we recruited children younger than 12 years scheduled for cranial neurosurgery in a large East‐African hospital. Patients were block‐randomized by age to intraoperative warming measures using Hibler's method (intervention) or warm air (comparator). Hibler's group patients were circumferentially wrapped in transparent plastic sheeting (providing a vapor‐trap) over a layer of cotton blankets, then laid on an insulating foam mattress. Warm air group patients were treated with forced‐air convection via an underlying Snuggle Warm™ Pediatric Full Body mattress. Allocated warming measures were initiated in the operating theatre and discontinued upon anesthesia emergence. Perioperative temperatures were measured using noninvasive forehead probes (SpotOn™). The primary outcome was incidence of hypothermia (core temperature < 36.0° for longer than 5 min). Our null hypothesis was that Hibler's method is inferior in efficacy to the warm air method by a margin exceeding 20%. Among secondary outcomes were duration of hypothermia as proportion of surgical duration, incidence of postoperative shivering and rescue measure requirements.ResultsWe analyzed data for 77 participants (Hibler's = 38; warm air = 39). There was no significant difference between the Hibler's and warm air arms of the study in the primary outcome of incidence of hypothermia (59.0% vs. 60.5% respectively; OR 1.07; 95% CI 0.43–2.65; p = .890). However, the risk difference (1.55%; 95% CI −0.20 to −0.24) exceeded the 0.2 margin and non‐inferiority could not be declared. There was considerable need for rescue measures in both groups (71.1 0% vs. 69.2%; OR 1.09; 95% CI 0.41–2.90; p = .861). There was no statistically significant difference between groups for any prespecified secondary outcome.ConclusionAlthough perioperative core temperatures were not significantly different, we could not declare an inexpensive heat‐preserving method non‐inferior to warm air convection in preventing intraoperative hypothermia in children undergoing anesthesia for cranial neurosurgery in a resource‐limited setting. The extensive need for rescue measures may have masked important differences.Trial Registration: US National Institutes of Health Clinicaltrials.gov database (ID no. NCT02975817).