Wash-in and wash-out of sevoflurane in a test-lung model: A comparison between Aisys and FLOW-i [version 2; referees: 2 approved, 1 approved with reservations]
Background: Modern anaesthesia workstations are reassuringly tight and are equipped with effective gas monitoring, thus providing good opportunities for low/minimal flow anaesthesia. A prerequisite for effective low flow anaesthesia is the possibility to rapidly increase and decrease gas concentrati...
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| Format: | Article |
| Language: | English |
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F1000 Research Ltd
2017-04-01
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| Series: | F1000Research |
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| Online Access: | https://f1000research.com/articles/6-389/v2 |
| _version_ | 1818843315216318464 |
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| author | Petter Jakobsson Madleine Lindgren Jan G. Jakobsson |
| author_facet | Petter Jakobsson Madleine Lindgren Jan G. Jakobsson |
| author_sort | Petter Jakobsson |
| collection | DOAJ |
| description | Background: Modern anaesthesia workstations are reassuringly tight and are equipped with effective gas monitoring, thus providing good opportunities for low/minimal flow anaesthesia. A prerequisite for effective low flow anaesthesia is the possibility to rapidly increase and decrease gas concentrations in the circle system, thereby controlling the depth of anaesthesia. Methods: We studied the wash-in and wash-out of sevoflurane in the circle system with fixed fresh gas flow and vaporizer setting. We compared two modern anaesthesia work stations, the Aisys (GE, Madison, WI, USA) and FLOW-i (Maquet, Solna, Sweden) in a test lung model. Results: We found fresh-gas flow to have, as expected, a major influence on wash-in, as well as wash-out of sevoflurane. The wash-in time to reach a stable circle 1 MAC (2.1%) decreased from an average of 547 ± 83 seconds with a constant fresh gas flow of 300 ml/min and vaporizer setting of 8%, to a mean of 38 ± 6 seconds at a fresh gas flow of 4 L/min. There were only minor differences between the two works-stations tested; the Aisys was slightly faster at both 300 and 4 L/min flow. Time to further increase circle end-tidal concentration from 1-1.5 MAC showed likewise significant associations to fresh gas and decreased from 330 ± 24 seconds at 300 ml/min. to less than a minute at constant 4 L/min (17 ± 11 seconds), without anaesthetic machine difference. Wash-out was also fresh gas flow dependent and plateaued at 7.5 L/min. Conclusions: Circle system wash-in and wash-out show clear fresh gas dependency and varies somewhat between the Aisys and Flow-i. The circle saturation, reaching 1 MAC end-tidal or increasing from 1-1.5 MAC can be achieved with both work-stations within 1.5 minutes at a constant fresh gas flow of 2 and 4 L/min. Wash-out plateaued at 7.5 L/min. |
| first_indexed | 2024-12-19T04:55:55Z |
| format | Article |
| id | doaj.art-4a004af9e08d40d7a704da97fed5371a |
| institution | Directory Open Access Journal |
| issn | 2046-1402 |
| language | English |
| last_indexed | 2024-12-19T04:55:55Z |
| publishDate | 2017-04-01 |
| publisher | F1000 Research Ltd |
| record_format | Article |
| series | F1000Research |
| spelling | doaj.art-4a004af9e08d40d7a704da97fed5371a2022-12-21T20:35:14ZengF1000 Research LtdF1000Research2046-14022017-04-01610.12688/f1000research.11255.212427Wash-in and wash-out of sevoflurane in a test-lung model: A comparison between Aisys and FLOW-i [version 2; referees: 2 approved, 1 approved with reservations]Petter Jakobsson0Madleine Lindgren1Jan G. Jakobsson2Faculty of Medicine, University of Lund, Lund, 221 00, SwedenDepartment of Anaesthesia & Intensive Care, Institution for Clinical Science, Karolinska Institutet, Danderyds University Hospital, Stockholm, 182 88 , SwedenDepartment of Anaesthesia & Intensive Care, Institution for Clinical Science, Karolinska Institutet, Danderyds University Hospital, Stockholm, 182 88 , SwedenBackground: Modern anaesthesia workstations are reassuringly tight and are equipped with effective gas monitoring, thus providing good opportunities for low/minimal flow anaesthesia. A prerequisite for effective low flow anaesthesia is the possibility to rapidly increase and decrease gas concentrations in the circle system, thereby controlling the depth of anaesthesia. Methods: We studied the wash-in and wash-out of sevoflurane in the circle system with fixed fresh gas flow and vaporizer setting. We compared two modern anaesthesia work stations, the Aisys (GE, Madison, WI, USA) and FLOW-i (Maquet, Solna, Sweden) in a test lung model. Results: We found fresh-gas flow to have, as expected, a major influence on wash-in, as well as wash-out of sevoflurane. The wash-in time to reach a stable circle 1 MAC (2.1%) decreased from an average of 547 ± 83 seconds with a constant fresh gas flow of 300 ml/min and vaporizer setting of 8%, to a mean of 38 ± 6 seconds at a fresh gas flow of 4 L/min. There were only minor differences between the two works-stations tested; the Aisys was slightly faster at both 300 and 4 L/min flow. Time to further increase circle end-tidal concentration from 1-1.5 MAC showed likewise significant associations to fresh gas and decreased from 330 ± 24 seconds at 300 ml/min. to less than a minute at constant 4 L/min (17 ± 11 seconds), without anaesthetic machine difference. Wash-out was also fresh gas flow dependent and plateaued at 7.5 L/min. Conclusions: Circle system wash-in and wash-out show clear fresh gas dependency and varies somewhat between the Aisys and Flow-i. The circle saturation, reaching 1 MAC end-tidal or increasing from 1-1.5 MAC can be achieved with both work-stations within 1.5 minutes at a constant fresh gas flow of 2 and 4 L/min. Wash-out plateaued at 7.5 L/min.https://f1000research.com/articles/6-389/v2Technology & Monitoring in Anesthesiology |
| spellingShingle | Petter Jakobsson Madleine Lindgren Jan G. Jakobsson Wash-in and wash-out of sevoflurane in a test-lung model: A comparison between Aisys and FLOW-i [version 2; referees: 2 approved, 1 approved with reservations] F1000Research Technology & Monitoring in Anesthesiology |
| title | Wash-in and wash-out of sevoflurane in a test-lung model: A comparison between Aisys and FLOW-i [version 2; referees: 2 approved, 1 approved with reservations] |
| title_full | Wash-in and wash-out of sevoflurane in a test-lung model: A comparison between Aisys and FLOW-i [version 2; referees: 2 approved, 1 approved with reservations] |
| title_fullStr | Wash-in and wash-out of sevoflurane in a test-lung model: A comparison between Aisys and FLOW-i [version 2; referees: 2 approved, 1 approved with reservations] |
| title_full_unstemmed | Wash-in and wash-out of sevoflurane in a test-lung model: A comparison between Aisys and FLOW-i [version 2; referees: 2 approved, 1 approved with reservations] |
| title_short | Wash-in and wash-out of sevoflurane in a test-lung model: A comparison between Aisys and FLOW-i [version 2; referees: 2 approved, 1 approved with reservations] |
| title_sort | wash in and wash out of sevoflurane in a test lung model a comparison between aisys and flow i version 2 referees 2 approved 1 approved with reservations |
| topic | Technology & Monitoring in Anesthesiology |
| url | https://f1000research.com/articles/6-389/v2 |
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