Figure 40-10 Changes in body heat content and distribution of heat within the body during the core temperature plateau. Elapsed time zero indicates the onset of arteriovenous shunt vasoconstriction, which causes the plateau. Core temperature decreased 1.3°C in 2 hours before constriction and then remained constant. The difference between core temperature and mean body temperature (which continued to decrease) indicates how much heat was retained in the core thermal compartment by thermoregulatory vasoconstriction. In this case, 22 ± 8 kcal was constrained to the core. Results are presented as means ± SD. (Redrawn with modification from Kurz A, Sessler DI, Christensen R, Dechert M: Heat balance and distribution during the core-temperature plateau in anesthetized humans. Anesthesiology 83:491–499, 1995.)