Figure 40-5 The vasoconstriction threshold was significantly less in the elderly (33.9 ± 0.6°C) than in younger patients (35.1 ± 0.3°C) during 60% nitrous oxide and isoflurane (0.75% end-tidal concentration). Filled circles indicate the vasoconstriction threshold in each patient; open circles show the mean and standard deviation in each group. (Redrawn from Kurz A, Plattner O, Sessler DI, et al: The threshold for thermoregulatory vasoconstriction during nitrous oxide/isoflurane anesthesia is lower in elderly than young patients. Anesthesiology 79:465–469, 1993.)