Closed circuit rebreathing to achieve inert gas wash-in for multiple breath wash-out
Multiple breath wash-out (MBW) testing requires prior wash-in of inert tracer gas. Wash-in efficiency can be enhanced by a rebreathing tracer in a closed circuit. Previous attempts to deploy this did not account for the impact of CO2 accumulation on patients and were unsuccessful. We hypothesised th...
| Main Authors: | , , , , , , |
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| Format: | Article |
| Language: | English |
| Published: |
European Respiratory Society
2016-01-01
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| Series: | ERJ Open Research |
| Online Access: | http://openres.ersjournals.com/content/2/1/00042-2015.full |
| _version_ | 1811279669747515392 |
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| author | Alex R. Horsley Katherine O'Neill Damian G. Downey J. Stuart Elborn Nicholas J. Bell Jaclyn Smith John Owers-Bradley |
| author_facet | Alex R. Horsley Katherine O'Neill Damian G. Downey J. Stuart Elborn Nicholas J. Bell Jaclyn Smith John Owers-Bradley |
| author_sort | Alex R. Horsley |
| collection | DOAJ |
| description | Multiple breath wash-out (MBW) testing requires prior wash-in of inert tracer gas. Wash-in efficiency can be enhanced by a rebreathing tracer in a closed circuit. Previous attempts to deploy this did not account for the impact of CO2 accumulation on patients and were unsuccessful. We hypothesised that an effective rebreathe wash-in could be delivered and it would not alter wash-out parameters. Computer modelling was used to assess the impact of the rebreathe method on wash-in efficiency. Clinical testing of open and closed circuit wash-in–wash-out was performed in healthy controls and adult patients with cystic fibrosis (CF) using a circuit with an effective CO2 scrubber and a refined wash-in protocol. Wash-in efficiency was enhanced by rebreathing. There was no difference in mean lung clearance index between the two wash-in methods for controls (6.5 versus 6.4; p=0.2, n=12) or patients with CF (10.9 versus 10.8; p=0.2, n=19). Test time was reduced by rebreathe wash-in (156 versus 230 s for CF patients, p<0.001) and both methods were well tolerated. End wash-in CO2 was maintained below 2% in most cases. Rebreathe–wash-in is a promising development that, when correctly deployed, reduces wash-in time and facilitates portable MBW testing. For mild CF, wash-out outcomes are equivalent to an open circuit. |
| first_indexed | 2024-04-13T00:59:53Z |
| format | Article |
| id | doaj.art-89edc922b9e44881b0c7ae4df5229c64 |
| institution | Directory Open Access Journal |
| issn | 2312-0541 |
| language | English |
| last_indexed | 2024-04-13T00:59:53Z |
| publishDate | 2016-01-01 |
| publisher | European Respiratory Society |
| record_format | Article |
| series | ERJ Open Research |
| spelling | doaj.art-89edc922b9e44881b0c7ae4df5229c642022-12-22T03:09:31ZengEuropean Respiratory SocietyERJ Open Research2312-05412016-01-012110.1183/23120541.00042-201500042-2015Closed circuit rebreathing to achieve inert gas wash-in for multiple breath wash-outAlex R. Horsley0Katherine O'Neill1Damian G. Downey2J. Stuart Elborn3Nicholas J. Bell4Jaclyn Smith5John Owers-Bradley6 Institute of Inflammation and Repair, Education and Research Centre, University of Manchester, Manchester, UK Centre for Infection and Immunity, Queen's University Belfast, Belfast, UK Belfast City Hospital, Belfast Health and Social Care Trust, Belfast, UK Centre for Infection and Immunity, Queen's University Belfast, Belfast, UK Bristol Royal Infirmary, University Hospitals Bristol NHS Foundation Trust, Bristol, UK Institute of Inflammation and Repair, Education and Research Centre, University of Manchester, Manchester, UK School of Physics and Astronomy, University of Nottingham, Nottingham, UK Multiple breath wash-out (MBW) testing requires prior wash-in of inert tracer gas. Wash-in efficiency can be enhanced by a rebreathing tracer in a closed circuit. Previous attempts to deploy this did not account for the impact of CO2 accumulation on patients and were unsuccessful. We hypothesised that an effective rebreathe wash-in could be delivered and it would not alter wash-out parameters. Computer modelling was used to assess the impact of the rebreathe method on wash-in efficiency. Clinical testing of open and closed circuit wash-in–wash-out was performed in healthy controls and adult patients with cystic fibrosis (CF) using a circuit with an effective CO2 scrubber and a refined wash-in protocol. Wash-in efficiency was enhanced by rebreathing. There was no difference in mean lung clearance index between the two wash-in methods for controls (6.5 versus 6.4; p=0.2, n=12) or patients with CF (10.9 versus 10.8; p=0.2, n=19). Test time was reduced by rebreathe wash-in (156 versus 230 s for CF patients, p<0.001) and both methods were well tolerated. End wash-in CO2 was maintained below 2% in most cases. Rebreathe–wash-in is a promising development that, when correctly deployed, reduces wash-in time and facilitates portable MBW testing. For mild CF, wash-out outcomes are equivalent to an open circuit.http://openres.ersjournals.com/content/2/1/00042-2015.full |
| spellingShingle | Alex R. Horsley Katherine O'Neill Damian G. Downey J. Stuart Elborn Nicholas J. Bell Jaclyn Smith John Owers-Bradley Closed circuit rebreathing to achieve inert gas wash-in for multiple breath wash-out ERJ Open Research |
| title | Closed circuit rebreathing to achieve inert gas wash-in for multiple breath wash-out |
| title_full | Closed circuit rebreathing to achieve inert gas wash-in for multiple breath wash-out |
| title_fullStr | Closed circuit rebreathing to achieve inert gas wash-in for multiple breath wash-out |
| title_full_unstemmed | Closed circuit rebreathing to achieve inert gas wash-in for multiple breath wash-out |
| title_short | Closed circuit rebreathing to achieve inert gas wash-in for multiple breath wash-out |
| title_sort | closed circuit rebreathing to achieve inert gas wash in for multiple breath wash out |
| url | http://openres.ersjournals.com/content/2/1/00042-2015.full |
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