Limb tourniquets and central temperature in anesthetized children

We have observed an association between the use of tourniquets for limb surgery and a progressive increase in body temperature in pediatric patients. Consequently, we evaluated the effect of leg tourniquet(s) on intraoperative nasopharyngeal temperature in pediatric patients. We measured central temperature in three groups of children anesthetized with halothane and nitrous oxide: those with unilateral tourniquets (n = 15), those with bilateral tourniquets (n = 8), and a control group not requiring tourniquets (n = 24). Intraoperative ambient temperatures were maintained near 23 degrees C, respiratory gases were actively heated and humidified, and skin was warmed using a circulating water blanket set at 38 degrees C. The control patients remained normothermic during anesthesia and surgery. In contrast, central temperature increased 1.0 +/- 0.6 degrees C in 90 min in those with one tourniquet and 1.7 +/- 0.6 degrees C in those with bilateral tourniquets. The tourniquet-induced hyperthermia appeared to result from decreased effective heat loss from distal skin and from constraint of metabolic heat to the central thermal compartment. These data suggest that pediatric patients requiring intraoperative tourniquets should not be aggressively warmed during surgery.