UNDER-BODY FORCED-AIR WARMING BLANKET VERSUS RESISTIVE HEATING BLANKET FOR PREVENTION OF HYPOTHERMIA DURING SPINAL SURGERY: A RANDOMIZED PROSPECTIVE STUDY

ABSTRACTBackground:Prevention of hypothermia in patients undergoing major posterior approach spinal surgery can be difficult, as alarge body surface is exposed to the cold environment of the operating theatre. We compared the efficacy of anew under-body forced-air warming blanket with that of a resistive heating blanket in preventing hypothermia.Methods:Sixty patients undergoing major posterior approach spinal surgery lasting for more than 2 hours were randomlyassigned to warming with a full under-body forced-air warming blanket or three segments of resistive heatingblankets, both set at 42°C. The ambient temperature was kept near 20°C. Nasopharyngeal, rectal and axillarytemperatures were measured at regular intervals. Changes in core temperature (average of nasopharyngealand rectal) over time were compared by the independent t-test.Results:The characteristics of the patients were comparable. The baseline core temperature was 36.36 ±0.38°C in theforced-air group and 36.27 ± 0.46°C in the resistive heating group. During the first hour, the core temperaturedecreased similarly from baseline in both groups. From 100 minutes after induction until the end of the surgery,core temperature rose in both groups. At the end of surgery, the core temperature was increased by 0.08± 0.09°C from baseline in the forced-air group but decreased by 0.40 ±0.04°C from baseline in the resistiveheating group. The difference in the change of the core temperature, at the end of the surgery, between thetwo groups is statistically significant (P<0.05).Conclusion:We demonstrated that the new under-body forced-air warming blanket is superior to the resistive heatingblanket in preventing hypothermia in patients undergoing major posterior approach spinal surgery.