Figure 40-23 Average (± SD) intraoperative esophageal temperatures (T_esoph ) during the cooling, temperature maintenance, and rewarming periods in eight neurosurgical patients who were cooled with endovascular heat-exchanging catheters in the vena cava. Time zero identified the beginning of each thermal management period; the duration of these periods differed in individual patients, depending on the length of surgery and other factors. The regression lines (gray lines) are shown for the cooling and rewarming periods. (Redrawn from Doufas AG, Akça O, Barry A, et al: Initial experience with a novel heat-exchanging catheter in neurosurgical patients. Anesth Analg 95:1752–1756, 2002.)