Figure 40-17 Intraoperative and postoperative core temperatures in patients assigned to general anesthesia (n = 20) and spinal anesthesia (n = 20). All patients were warmed with forced air during the postoperative period. Core temperature did not differ significantly during surgery, but it increased significantly faster postoperatively in patients given spinal anesthesia (1.2 ± 0.1°C/hr versus 0.7 ± 0.2°C/hr, means ± SD). (Redrawn from Szmuk P, Ezri T, Sessler DI, et al: Spinal anesthesia only minimally increases the efficacy of postoperative forced-air rewarming. Anesthesiology 87:1050–1054, 1997.)