Intra‐operative rewarming with Hot Dog ® resistive heating and forced‐air heating: a trial of lower‐body warming

Resistive heating is an alternative to forced-air warming which is currently the most commonly used intra-operative warming system. We therefore tested the hypothesis that rewarming rates are similar with Hot Dog(®) (Augustine Biomedical) resistive and Bair Hugger(®) (Arizant) forced-air heating systems. We evaluated 28 patients having major maxillary tumour surgery. During the establishment of invasive monitoring, patients became hypothermic, dropping their core temperature to about 35 °C. They were then randomly assigned to rewarming with lower-body resistive (n = 14) or forced-air (n = 14) heating, with each system set to 'high'. Our primary outcome was the rewarming rate during active heating over a core temperature range from 35 to 37 °C. Morphometric characteristics were comparable in both groups. Temperature increased at twice the rate in patients assigned to forced-air warming, with an estimated mean (SE) slope of 0.49 (0.03) °C.h(-1) vs 0.24 (0.02) °C.h(-1) (p < 0.001). Resistive heating warmed at half the rate of forced air.