Figure 7-23 Effects of desflurane (red squares) and isoflurane (black squares) on sympathetic nerve activity (top), heart rate (middle), and mean arterial pressure (bottom) in healthy volunteers. Desflurane or isoflurane administration began 2 minutes after anesthetic induction with sodium thiopental (STP). Sympathetic nerve excitation, tachycardia, and hypertension were observed in subjects receiving desflurane. *, Different (P < .05) group response; †, desflurane response different (P < .05) from STP value; ¥, isoflurane response different (P < .05) from STP value. (Adapted from Ebert TJ, Muzi M: Sympathetic hyperactivity during desflurane anesthesia in healthy volunteers: A comparison with isoflurane. Anesthesiology 79:444–453, 1993.)