Figure 40-21 Core temperature as a function of time in patients assigned to the circulating-water, forced-air, and carbon-fiber (resistive heating) groups. Temperature changes in the control group differed significantly from changes in the other groups after 150 elapsed minutes. Temperatures in the circulating-water and carbon-fiber groups never differed significantly. Results are presented as means ± SEM. Despite similar efficacy, carbon-fiber heating is associated with patient burns and should be avoided. (Redrawn from Negishi C, Hasegawa K, Mukai S, et al: Resistive-heating and forced-air warming are comparably effective. Anesth Analg 96:1683–1687, 2003.)