[Prevention of intraoperative hypothermia in children].
Children are very sensible to the occurrence of intraoperative hypothermia (HT) (core temperature < or = 36.0 degrees C) during general anaesthesia because their regulation capacity is less effective than in adults and due to a large skin-surface area compared with their body mass. We compared the efficacy of different heating devices to prevent HT in children during surgery.


METHODS
With approval of the local ethics committee 50 children between one and seven years, scheduled for peripheral surgery lasting at least 2 hours were included in this study. Anaesthesia was standardized in all patients. Patients were randomly divided into 5 groups. In group 1, in addition to the usual cotton blankets, room temperature was elevated to 27-28 degrees C. In group 2, room temperature was maintained at 27-28 degrees C, and the patients were additionally wrapped into an aluminum blanket. In group 3, elevated room temperature was combined with a convective heating blanket. Patients in group 4 were warmed with an aluminum blanket, while the room temperature was maintained at 22 degrees C. In group 5, room temperature was maintained at 22 degrees C and patients were warmed with a convective heating device (Tab. 1). Room and core body temperature (tympanon membrane) were continuously measured. ANOVA and Fisher's exact Test (significance level: p < 0.05) were performed for the statistical analysis of the results.


RESULTS
The demographic data of all 5 groups, the infused fluid volume and the anaesthetic technique were similar. There were no significant differences concerning age, height and weight of the pediatric patients (Tab. 2). The core temperature decreased by -1.7 degrees C in group 1. In group 4 core temperature decreased by -1.6 degrees C. Using a convective warming system in normal ambient temperature (group 5) core temperature increased by 0.2 degree C and was as effective in the prevention of HT as group 2. A significant increase in core temperature occurred in group 3 +0.7 degree C (Tab. 3 and Fig. 1).


CONCLUSIONS
OR temperature seems to be a critical factor influencing heat loss. Increasing OR temperature and covering with cotton sheets was not effective in preventing the heat loss. Increasing room temperature in combination with aluminum sheets is one alternative to prevent HT. Our study shows that the use of a convective warming device prevents HT during a 2-hour surgery in young children even at a OR temperature of about 22 degrees C. In conclusion, in pediatric patients the use of a convective heating system proved to be an effective alternative to room heating.
Klinik für Anaesthesiologie, Intensiv- und Schmerztherapie, Universitätsklinik Bergmannsheil Bochum.
J
J
Leben
M
M
Tryba
K
K
Kurz-Müller
W
W
Schregel
D001831:Body Temperature; D001833:Body Temperature Regulation / Q000502:physiology; D002675:Child, Preschool; D005260:Female; D006801:Humans; D007035:Hypothermia / Q000517:prevention & control*; D007223:Infant; D007431:Intraoperative Complications / Q000517:prevention & control*; D008297:Male; D013696:Temperature; D013997:Time Factors