Modeling iatrogenic intraoperative hyperthermia from external warming in children: A pooled analysis from two prospective observational studies.BACKGROUND
 Maintenance of normothermia is an important quality metric in pediatric anesthesia.  While inadvertent hypothermia is effectively prevented by forced-air warming, this therapeutic approach can lead to iatrogenic hyperthermia in young children.


 To estimate the influence of external warming by forced air on the development of intraoperative hyperthermia in anesthetized children aged 6 years or younger.


 Secondary outcomes were the incidence of hyperthermia (body core temperature >38°C), the probability of hyperthermia over the duration of warming in relation to age and surface-area-to-weight ratio, respectively, analyzed by multiple logistic regression models.  The influence of baseline temperature on hyperthermia was estimated using a Cox proportional hazards model.


 Overall, 33 children were hyperthermic at at least one measurement point.  The odds ratios of hyperthermia were 1.14 (95%-CI: 1.07-1.22) or 1.13 (95%-CI: 1.06-1.21) for every 10 min of warming therapy in a model with age or surface-area-to weight ratio (ceteris paribus), respectively.  An increase of 0.1°C in baseline temperature increased the hazard of becoming hyperthermic by a factor of 1.33 (95%-CI: 1.23-1.43).


 In children, external warming by forced-air needs to be closely monitored and adjusted in a timely manner to avoid iatrogenic hyperthermia especially during long procedures, in young age, higher surface-area-to-weight ratio, and higher baseline temperature.
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