Background: Peri-operative hypothermia is very common and associated with many complications. Hypotheremia is most evident in first two hours due to redistribution of heat after induction of general anaesthesia. The study was conducted to compare the effect of pre-warming and intraoperative warming with only intraoperative warming in patients undergoing long duration surgeries under general anaesthesia where following parameters were studied: Core body temperature as a primary outcome and hemodynamic parameters, extubation time, post anaesthesia recovery and postoperative shivering as secondary outcomes.

Methods: In this prospective interventional study, 40 patients between 18-70 years of age were divided into two groups. Group A received preoperative as well as intraoperative forced air warming. Group B received only intraoperative forced air warming with Bair Hugger. Intra-operatively, core body temperature and hemodynamics were monitored. Extubation time and post operative recovery score were recorded after surgery.

Results: It was observed that after induction of general anaesthesia core temperature started decreasing in both the groups but the fall was more in group B, which was statistically significant till 150 minutes. After that period the
difference was insignificant till the end of the surgery. No significant difference in any other parameter studied was observed in both the groups.

Conclusion: Preoperative warming with forced air warmer is definitely effective in preventing redistribution hypothermia for initial two hours of surgery. However, the overall immediate outcome is not affected as per observations made in our study.