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- Edmark, Lennart, 1954-, et al.
(författare)
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Pressure-controlled versus manual facemask ventilation for anaesthetic induction in adults : A randomised controlled non-inferiority trial
- 2023
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Ingår i: Acta Anaesthesiologica Scandinavica. - : John Wiley & Sons. - 0001-5172 .- 1399-6576. ; 67:10, s. 1356-1362
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Tidskriftsartikel (refereegranskat)abstract
- Background: Pressure-controlled face mask ventilation (PC-FMV) with positive end-expiratory pressure (PEEP) after apnoea following induction of general anaesthesia prolongs safe apnoea time and reduces atelectasis formation. However, depending on the set inspiratory pressure, a delayed confirmation of a patent airway might occur. We hypothesised that by lowering the peak inspiratory pressure (PIP) when using PC-FMV with PEEP, confirmation of a patent airway would not be delayed as studied by the first return of CO2, compared with manual face mask ventilation (Manual FMV).Methods: This was a single-centre, randomised controlled non-inferiority trial. Seventy adult patients scheduled for elective day-case surgery under general anaesthesia with body mass index between 18.5 and 29.9 kg m(-2), American Society of Anesthesiologists (ASA) classes I-III, and without anticipated difficult FMV, were included. Before the start of pre-oxygenation and induction of general anaesthesia, participants were randomly allocated to receive ventilation with either PC-FMV with PEEP, at a PIP of 11 and a PEEP of 6 cmH(2)O or Manual FMV, with the adjustable pressure-limiting valve set at 11 cmH(2)O. The primary outcome variable was the number of ventilatory attempts needed until confirmation of a patent airway, defined as the return of at least 1.3 kPa CO2.Results: The return of >= 1.3 kPa CO2 on the capnography curve was observed after mean +/- SD, 3.6 +/- 4.2 and 2.5 +/- 1.9 ventilatory attempts/breaths with PC-FMV with PEEP and Manual FMV, respectively. The difference in means (1.1 ventilatory attempts/breaths) had a 99% CI of similar to 1.0 to 3.1, within the accepted upper margin of four breaths for non-inferiority.Conclusion: Following induction of general anaesthesia, PC-FMV with PEEP was used without delaying a patent airway as confirmed with capnography, if moderate pressures were used.
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| 2. |
- Jonsson, Anthon, 1993-, et al.
(författare)
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Test rig for submerged transmissions in wave energy converters as a development tool for dynamic sealing systems
- 2023
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Ingår i: Proceedings of the 15th European Wave and Tidal Energy Conference (EWTEC 2023), Bilbao, 3-7 September, 2023.
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Konferensbidrag (refereegranskat)abstract
- A submerged transmission, fitted with a dynamic sealing system, in a wave energy converter (WEC) serves the purpose of transmitting the force, absorbed by a wave activated body, to an encapsulated power take-off (PTO) system, while preventing seawater from entering the capsule. Dry generator operation is generally a prerequisite for attaining long technical service life. Little attention seems to be devoted in publications to the study of dynamic sealing systems in WECs, and to test rigs for experimental verification and/or evaluation of the ability/performance of existing dynamic sealing systems in a controlled laboratory environment. This paper begins by presenting some of our earlier research within the focus area of dynamic sealing systems, incl. design considerations and typical operating conditions. This part also presents the 1st laboratory test rig, used for verifying the sealing ability of the piston rod mechanical lead-through design in the 1st and 2nd full-scale experimental WEC prototype from Uppsala University. In 2021 project DynSSWE (Dynamic Sealing Systems for Wave Energy) was initiated. Drawing from experience, the project includes development of a new test rig, representing a tool for further development of dynamic sealing systems. This paper introduces steps in the design and development process of that new test rig, enabling accelerated long-term test runs with a setup of multiple piston rod specimens. The test specimens’ will be surface treated differently with the aim of improving the prospects of a long maintenance free service life. Since the new test rig is in the design stage, seal testing results are not yet reported. The presented work is funded by the Swedish energy agency with the aim of improving subsystem performance in wave energy devices.
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