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. 2012 Oct;28(4):470-5.
doi: 10.4103/0970-9185.101916.

A randomized prospective study of desflurane versus isoflurane in minimal flow anesthesia using "equilibration time" as the change-over point to minimal flow

Tanuja Mallik  1 , S Aneja, R Tope, V Muralidhar
Affiliations

A randomized prospective study of desflurane versus isoflurane in minimal flow anesthesia using "equilibration time" as the change-over point to minimal flow

Tanuja Mallik et al. J Anaesthesiol Clin Pharmacol. 2012 Oct.

Abstract

Background: In the administration of minimal flow anesthesia, traditionally a fixed time period of high flow has been used before changing over to minimal flow. However, newer studies have used "equilibration time" of a volatile anesthetic agent as the change-over point.

Materials and methods: A randomized prospective study was conducted on 60 patients, who were divided into two groups of 30 patients each. Two volatile inhalational anesthetic agents were compared. Group I received desflurane (n = 30) and group II isoflurane (n = 30). Both the groups received an initial high flow till equilibration between inspired (Fi) and expired (Fe) agent concentration were achieved, which was defined as Fe/Fi = 0.8. The mean (SD) equilibration time was obtained for both the agent. Then, a drift in end-tidal agent concentration during the minimal flow anesthesia and recovery profile was noted.

Results: The mean equilibration time obtained for desflurane and isoflurane were 4.96 ± 1.60 and 16.96 ± 9.64 min (P < 0.001). The drift in end-tidal agent concentration over time was minimal in the desflurane group (P = 0.065). Recovery time was 5.70 ± 2.78 min in the desflurane group and 8.06 ± 31 min in the isoflurane group (P = 0.004).

Conclusion: Use of equilibration time of the volatile anesthetic agent as a change-over point, from high flow to minimal flow, can help us use minimal flow anesthesia, in a more efficient way.

Keywords: Desflurane; equilibration time; fixed time; isoflurane; minimal flow; volatile anesthetic agent.

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Conflict of interest statement

Conflict of Interest: None declared.

Figures

Figure 1
Figure 1
Special connector for return of sampling gas used. (a) One end of the connector attached to the expiratory limb of breathing circuit. (b) Second end of connector attached to the exhaust of respiratory gas monitors (RGM)
Figure 2
Figure 2
Comparison of mean end-tidal volatile anesthetic partial pressure (MFe) concentration
Figure 3
Figure 3
Comparison of mean end-tidal volatile anesthetic partial pressure (MFe) concentration
Figure 4
Figure 4
Comparison of end-tidal nitrous oxide concentration over time, while patient receiving minimal flow anesthesia with desflurane or isoflurane as volatile anesthetic agent
See this image and copyright information in PMC

References

    1. Bengtson JP. Reservation of humidity and heat of respiratory gases during anesthesia a laboratory investigation. Acta Anaesth Scand. 1987;31:127–31. - PubMed
    1. Ooi NR, Lee DJ, Soni N. New agent, the circle system and short procedure. Anaesthesia. 1997;52:364–81. - PubMed
    1. Lee DJ, Robinson DL, Soni N. Efficiency of a circle system for short surgical cases comparison of desflurane with isoflurane. Br J Anaesth. 1996;76:780–2. - PubMed
    1. Baxter AD. Low and minimal flow anaesthesia. Can J Anaesth. 1997;44:643–53. - PubMed
    1. Coetzee JF, Stewart LJ. Fresh gas flow is not the only determinant of volatile agent consumption, a multicentric study of low flow anaesthesia. Br J Anaesth. 2002;88:46–55. - PubMed