Ryu K, et al. - Researchers performed comparison of the surgical pleth index (SPI) values produced by equi-minimum alveolar concentration (MAC) of two commonly used volatile anesthetics, sevoflurane and desflurane. In this work, equi-MAC of sevoflurane and desflurane did not yield similar surgical pleth index values. Thereby suggesting sevoflurane and desflurane as different regarding analgesic properties at equipotent concentrations.