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Published on: September 24, 2020
Saving sevoflurane and hastening emergence from anaesthesia using an anaesthetic-conserving device
1Department of Anesthesiology, The University of Tokyo, Tokyo, Japan. nishit-tky@umin.ac.jp
Background And Objective:
This study compared an anaesthetic-conserving device (AnaConDa) and a conventional vaporizer in terms of sevoflurane consumption and emergence from anaesthesia using a total gas flow of 4 l min(-1), with a rebreathing circuit.
Patients And Methods:
Twenty-four patients for gastrectomy, aged 30-70 years, were divided into AnaConDa and control groups. Anaesthesia was induced with midazolam, propofol, fentanyl and vecuronium. The total gas flow was fixed at 4 l min(-1) (nitrous oxide 2 l min(-1) and oxygen 2 l min(-1)). Sevoflurane administration was started at 0.5% (vaporizer setting) in the control group and 25 ml h(-1) in the AnaConDa group, then the end-tidal sevoflurane concentration was kept between 0.3 and 0.5% in both groups. Analgesia was obtained with intermittent epidural administration of mepivacaine. The time to first detection of end-tidal sevoflurane, sevoflurane consumption and emergence time were compared between the two groups.
Results:
The AnaConDa group showed a significantly longer time to first detection of end-tidal sevoflurane (211 +/- 75 vs. 40 +/- 18 s), smaller sevoflurane consumption (12 +/- 3 vs. 42 +/- 9 ml), and shorter emergence time (12 +/- 2 vs. 16 +/- 1 min) than the control group.
Conclusion:
The AnaConDa could decrease sevoflurane consumption and hasten emergence from anaesthesia, but increasing sevoflurane concentration with AnaConDa at the start of anaesthesia might take longer than that with a conventional vaporizer.
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