Background
Inadvertent perioperative hypothermia (IPH) defined as core temperature below 36.0 °C is a common complication of general anesthesia with prevalence up to 70%. Warming of peripheral tissues prior to induction of anesthesia reduces the central to peripheral temperature gradient, thereby minimizing central heat loss due to heat redistribution, after induction of anesthesia. This study aimed to evaluate the effect of prewarming on post-induction core temperature and incidence of perioperative inadvertent hypothermia leading to postanesthetic shivering (PAS) in patients undergoing general anesthesia.
Results
The mean decrease in core temperature in the unwarmed group was 0.7 °C (+ /- 0.23) compared with a 0.2 °C decrease (+ /- 0.06) in the prewarmed group of patients. A total of 31.70% of patients in the unwarmed group developed IPH compared with one patient (1.7%) in the prewarmed group shortly after onset. Twenty-six patients (43.30%) in the unwarmed group had hypothermia at the end of surgery, compared with one patient (1.7%) in the prewarmed group. Shivering was observed in 46% of patients in the unwarmed group, while no shivering was observed in the prewarmed group.
Conclusions
Preoperative warming is an effective intervention to reduce the frequency of core temperature drops after induction of anesthesia, thereby preventing inadvertent perioperative hypothermia and the incidence of postoperative shivering.