Effectiveness of prewarming in prevention of inadvertent intraoperative hypothermia

Background: Inadvertent perioperative hypothermia (IPH), defined as a perioperative core temperature < 36 °C is attributable to redistribution of body heat from the core to peripheries during the initial phase of anaesthesia and is difficult to treat. We conducted this study to find the effectiveness of pre-warming in preventing the occurrence of hypothermia intraoperatively in adult patients undergoing elective laparotomy under general anaesthesia. Material and Methods: Forty-four adult patients undergoing elective laparotomy were randomized into two groups of 22 each. Patients in Group P were prewarmed for 60 minutes prior to induction and those in Group C did not receive prewarming. Results: Patients in Group P had a significantly higher peripheral temperature at induction compared to those in Group C (p = 0.025), whereas the core temperature at induction was found to be comparable between the 2 groups. The core to peripheral temperature gradient was found to be lower in group P when compared to group C and the difference was statistically significant (p = 0.042). The core temperature dropped to less than 35 °C in the first two hours following induction in 2 patients in Group P and in 14 patients in group C (p < 0.001). The rate of drop in the core temperature was higher in group C compared to group P (p=0.002).The mean peripheral temperature as well as the core temperature in group P was significantly higher than in group C from induction to 60th minute, and it was statistically significant. Conclusion: In the first 2 hours post induction, prewarming is effective in preventing the drop in core temperature and reduces the rate of drop in core temperature. Prewarming is effective in reducing the core to peripheral temperature gradient at induction.