The aim of this study is to compare the peripheral perfusion index values produced by equi-MAC of sevoflurane and desflurane in patients undergoing single-agent inhalation anesthesia.

Ether derivative anesthetics, including sevoflurane and desflurane, have direct activity on vascular tissue and both are vasodilators. However, there has been no direct comparison of vasodilative effect between sevoflurane and desflurane in vivo in humans. Peripheral perfusion index derived from photoplethysmographic waveform reflects peripheral vasomotor tone. Therefore, the purpose of this study is to compare the peripheral perfusion index values produced by sevoflurane and desflurane at equipotent concentration in patients undergoing single-agent inhalation anesthesia.

Inclusion Criteria:

• patients aged between 19 and 65 yr
• patients with American Society of Anesthesiologists physical status classification I or II
• patients scheduled for elective arthroscopic knee surgery under general anesthesia
• patients obtaining written informed consent

Exclusion Criteria:

• patients with a history of any disease associated with the autonomic nervous system
• patients receiving any medication affecting the sympathetic or parasympathetic nervous systems
• patients with cardiac arrhythmia, diabetes mellitus, and alcohol or drug abuse
• pregnant women