Background Minimum alveolar concentration (MAC) has traditionally been used to compare the potency of volatile anesthetics. However, as it reflects the spinal mechanism of immobility rather than the cerebral mechanism of analgesia and hypnosis, it is doubtful that equi-MAC connotes equivalent analgesic or hypnotic potency. The level of analgesia and hypnosis can be assessed using surgical pleth index and bispectral index (BIS) values, respectively. This study was designed to compare the surgical pleth index and BIS values produced by equi-MAC of desflurane and sevoflurane in patients undergoing single-agent volatile anesthesia. Methods Eighty-nine patients were randomly allocated to two groups receiving either desflurane (n = 44) or sevoflurane (n = 45). Anesthesia was only maintained with assigned volatile anesthetic of age-corrected 1.0 MAC. Surgical pleth index values as an analgesic estimate and BIS values as a hypnotic estimate were obtained under standard tetanic stimulation. Results Post-stimulation surgical pleth index values (mean ± SD), the primary outcome, were significantly lower for the desflurane group than those for the sevoflurane group (49 ± 10 vs. 64 ± 14, difference, 15 [95% CI, 10 to 20], P < 0.001). The desflurane group showed significantly lower poststimulation BIS values (median [interquartile range]) than the sevoflurane group (36 [31 to 41] vs. 41 [38 to 47], difference, 6 [95% CI, 2 to 9], P = 0.001). Conclusions During a steady-state of 1.0 MAC, desflurane and sevoflurane did not cause similar surgical pleth index and BIS values under the standardized nociceptive stimulus. These findings suggest that equi-MAC of desflurane and sevoflurane may not ensure equivalent analgesic or hypnotic potency.
Background: Traditionally, minimum alveolar concentration (MAC) has been used as the standard measure to compare the potencies of volatile anesthetics. However, it reflects the spinal mechanism of immobility rather than the subcortical mechanism of analgesia. Recently, the surgical pleth index (SPI) derived from photoplethysmographic waveform was shown to reflect the intraoperative analgesic component. This study was designed to compare the SPI values produced by equi-MAC of two commonly used volatile anesthetics, sevoflurane and desflurane.Methods: Seventy-two patients undergoing arthroscopic shoulder surgery were randomly assigned to two groups receiving either sevoflurane (n = 36) or desflurane (n = 36). General anesthesia was maintained with the respective volatile anesthetic only. A vaporizer was adjusted to maintain end-tidal anesthetic concentration at age-corrected 1.0 MAC throughout the study period. The SPI value as an analgesic estimate and the bispectral index (BIS) value as a hypnotic estimate were recorded at predefined time points during the standardized surgical procedure.Results: During the steady state of age-corrected 1.0 MAC, mean SPI values throughout the entire study period were significantly higher in the sevoflurane group than in the desflurane group (38.1 ± 12.8 vs. 30.7 ± 8.8, respectively, P = 0.005), and mean BIS values were significantly higher in the sevoflurane group than in the desflurane group (40.7 ± 5.8 vs. 36.8 ± 6.2, respectively, P = 0.008).Conclusions: Equi-MAC of sevoflurane and desflurane did not produce similar surgical pleth index values. Therefore, sevoflurane and desflurane may have different analgesic properties at equipotent concentrations.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.
hi@scite.ai
10624 S. Eastern Ave., Ste. A-614
Henderson, NV 89052, USA
Copyright © 2024 scite LLC. All rights reserved.
Made with 💙 for researchers
Part of the Research Solutions Family.