Sevoflurane in low-flow anesthesia using “equilibration point”

Abstract

Context:While giving low-flow anesthesia, it is a routine practice to give fixed duration of initial high-flow. This study was conducted to show the use of equilibration point as changeover point from initial high-flow to low-flow.Aims:It was to compare the use of equilibration point, hemodynamics, end-tidal agent concentration, recovery time, and recovery score between isoflurane and sevoflurane.Settings and Design:It was a prospective randomized study conducted on 100 patients who were admitted for elective surgery expected to be < 2 h duration.Materials and Methods:Patients were randomly assigned to one of the two groups of 50 each. Group I received isoflurane and Group S sevoflurane as an inhalational agent.Statistical Analysis:The observations obtained in both the groups were recorded and compared. Analysis was done using unpaired t-test and Chi-square test.Results:Hemodynamic parameters were comparable in both the groups. The mean equilibration times obtained for sevoflurane and isoflurane were 8.22 ± 1.060 min and 17.24 ± 10.2 min, respectively. The drift in end-tidal agent concentration over time was less in sevoflurane group. Mean recovery time was 7.92 ± 1.56 min in the sevoflurane group and 12.89 ± 3.45 min in the isoflurane group (P = 0.001). There was no significant difference between intraoperative and postoperative complications.Conclusion:Use of equilibration time of the volatile anesthetic agent as a changeover point, from high-flow to low-flow, can help us to use circle system with low-flow anesthesia in a more efficient way, especially with newer anesthetics such as sevoflurane.

The effect of low flow anesthesia on hemodynamic and peripheral oxygenation parameters in obesity surgery

“… 23 , 24 Many studies have shown that low-flow anesthesia is similar to or better than high-flow anesthesia in terms of recovery times. 10 , 25 In the present study, rescue times were similar in both groups, consistent with the findings of other studies.…”

Different fresh gas flows in prone position under general anesthesia: comparison of costs and effects on airway and endotracheal cuff pressures

“…We used sevoflurane as an inhaled anesthetic agent. In their study, McGain et al [9] and Chatrath et al [10] suggested switching from desflurane to sevoflurane to minimize the cost and environmental impact of inhalation anesthesia, based on the high cost, low potency, and greater greenhouse gas effect of desflurane.…”

A randomised prospective comparison of equilibration point and changing gas composition during low-flow anaesthesia with sevoflurane vs desflurane

“…have documented mean equilibration time of 8 min for sevoflurane, which is much more than what we recorded (4.59 ± 0.77 min). [5] They used 2.6% concentration of sevoflurane for all patients while we used age-specific MAC value that may have shortened the equilibration time in some cases reducing the average. In the earlier studies, Thepakorn et al .…”

“…In the earlier studies, Thepakorn et al . have used 1:1:12 wash in the scheme of desflurane using 1 L O 2 and N 2 O each and 12% desflurane[25] that yielded a shorter wash-in period for desflurane. However, it caused tachycardia and hypotension.…”

“…From the previous study by Chatrath et al ., the equilibration point of sevoflurane was 8.22 (±1.060) min. [5] Power analysis using Cochrane's formula with above SD before the study showed that 25 patients in each of the two groups would allow an 80% chance of detecting a 30% difference in equilibration point of desflurane and sevoflurane in LFA. Expecting a few drop-outs, 30 patients were enrolled in each group.…”