Comparison of Entropy Values of the Sevoflurane vs Isoflurane at Equal Minimum Alveolar Concentration in Patients Undergoing General Anesthesia during Wash-in and Wash-out Phases: A Prospective Randomized Study
Nikhila Karanth, R Nisarga, Shankar Kantharaju
Keywords :
Entropy, General anesthesia, Isoflurane, Minimum alveolar concentration, Sevoflurane
Background: General anesthetics produce separate identifiable anesthetic substates to different extents via agent-specific actions at discrete anatomic sites in the central nervous system (CNS) through different molecular targets. An important consequence of this complexity is that minimum alveolar concentration (MAC), which is exclusively based on motor response, might not proportionately reflect other components of anesthesia. This study compared the entropy values of the sevoflurane vs isoflurane at equal MAC.
Aims and objectives: To assess the entropy values, hemodynamic parameters, and safety profile at equi-MAC of the sevoflurane vs isoflurane.
Methodology: This study was done on a total of 60 patients aged 20–40 years, American Society of Anesthesiologists (ASA) I and II posted for elective surgery under general anesthesia. Patients were divided randomly into two groups: Group I (received isoflurane) and group S (received sevoflurane). At wash-in and wash-out phases with equal MAC, entropy values were measured (at 0.5 MAC, 1.0 MAC, and 1.5 MAC). Hemodynamic parameters were also noted.
Results: The demographic data were comparable between both groups. There were significantly lower entropy values with sevoflurane than with isoflurane at different MAC values, except at the baseline and end of surgery (p < 0.05). Hemodynamic parameters were comparable in both groups.
Conclusion: Sevoflurane is a better hypnotic agent as it produces lower entropy values when compared with isoflurane.
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