The effect of expiratory flow limitation on supine persistent hyperinflation in COPD: a prospective observational study
Introduction COPD is characterised by airflow obstruction, expiratory airway collapse and closure causing expiratory flow limitation (EFL) and hyperinflation. Supine posture may worsen ventilatory function in COPD, which may cause hyperinflation to persist and contribute to symptoms of orthopnoea an...
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| Format: | Article |
| Language: | English |
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European Respiratory Society
2024-11-01
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| Series: | ERJ Open Research |
| Online Access: | http://openres.ersjournals.com/content/10/6/00255-2024.full |
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| author | Meera Srinivasan Hannah Pollard David G. Chapman Katrina Tonga Kieran Patel Kaj Blokland David Touma Cindy Thamrin Troy Cross Kim Prisk Gregory G. King |
| author_facet | Meera Srinivasan Hannah Pollard David G. Chapman Katrina Tonga Kieran Patel Kaj Blokland David Touma Cindy Thamrin Troy Cross Kim Prisk Gregory G. King |
| author_sort | Meera Srinivasan |
| collection | DOAJ |
| description | Introduction
COPD is characterised by airflow obstruction, expiratory airway collapse and closure causing expiratory flow limitation (EFL) and hyperinflation. Supine posture may worsen ventilatory function in COPD, which may cause hyperinflation to persist and contribute to symptoms of orthopnoea and sleep disturbance. Our aim was to determine the impact of supine posture on hyperinflation, dynamic elastance and EFL in COPD and healthy subjects. We hypothesised that changes in hyperinflation in supine posture are influenced by EFL and gas trapping in COPD.
Methods
Clinically stable COPD patients (compatible symptoms, smoking >10 pack-years, obstructed spirometry) and healthy controls underwent oscillometry in the seated and supine positions. Hyperinflation was measured by inspiratory capacity (IC) and the ratio of IC to total lung capacity (IC/TLC) while seated and supine EFL was measured as the difference in mean inspiratory and mean expiratory oscillatory reactance at 5 Hz (Xrs5). Relationships between IC, IC/TLC and Xrs5, were examined by Spearman correlation.
Results
42 COPD patients demonstrated no change in IC/TLC from seated (0.31 L) to supine (0.32 L) position (p=0.079) compared to significant increases seen in 14 control subjects (0.37 L seated versus 0.44 L supine; p<0.001). In COPD, worse dynamic elastance (Xrs5 rs 0.499; p=0.001) and EFL (ΔXrs5 rs −0.413; p=0.007), along with increased age and lower body-mass-index were predictors of supine hyperinflation.
Conclusion
Supine persistent hyperinflation occurs in COPD and is associated with increased dynamic elastance and EFL, likely the result of increased airway closure due to gravitational redistribution of lung mass. |
| format | Article |
| id | doaj-art-ad57526a3e434efabbb435d61329f446 |
| institution | Kabale University |
| issn | 2312-0541 |
| language | English |
| publishDate | 2024-11-01 |
| publisher | European Respiratory Society |
| record_format | Article |
| series | ERJ Open Research |
| spelling | doaj-art-ad57526a3e434efabbb435d61329f4462025-01-14T09:50:21ZengEuropean Respiratory SocietyERJ Open Research2312-05412024-11-0110610.1183/23120541.00255-202400255-2024The effect of expiratory flow limitation on supine persistent hyperinflation in COPD: a prospective observational studyMeera Srinivasan0Hannah Pollard1David G. Chapman2Katrina Tonga3Kieran Patel4Kaj Blokland5David Touma6Cindy Thamrin7Troy Cross8Kim Prisk9Gregory G. King10 The Department of Respiratory and Sleep Medicine, Royal North Shore Hospital, St Leonards, NSW, Australia The Department of Respiratory and Sleep Medicine, Royal North Shore Hospital, St Leonards, NSW, Australia The Department of Respiratory and Sleep Medicine, Royal North Shore Hospital, St Leonards, NSW, Australia The Department of Respiratory and Sleep Medicine, Royal North Shore Hospital, St Leonards, NSW, Australia The Department of Respiratory and Sleep Medicine, Royal North Shore Hospital, St Leonards, NSW, Australia The Department of Respiratory and Sleep Medicine, Royal North Shore Hospital, St Leonards, NSW, Australia The Department of Respiratory and Sleep Medicine, Royal North Shore Hospital, St Leonards, NSW, Australia Airway Physiology and Imaging Group, The Woolcock Institute of Medical Research, Macquarie University, Sydney, NSW, Australia Airway Physiology and Imaging Group, The Woolcock Institute of Medical Research, Macquarie University, Sydney, NSW, Australia Airway Physiology and Imaging Group, The Woolcock Institute of Medical Research, Macquarie University, Sydney, NSW, Australia The Department of Respiratory and Sleep Medicine, Royal North Shore Hospital, St Leonards, NSW, Australia Introduction COPD is characterised by airflow obstruction, expiratory airway collapse and closure causing expiratory flow limitation (EFL) and hyperinflation. Supine posture may worsen ventilatory function in COPD, which may cause hyperinflation to persist and contribute to symptoms of orthopnoea and sleep disturbance. Our aim was to determine the impact of supine posture on hyperinflation, dynamic elastance and EFL in COPD and healthy subjects. We hypothesised that changes in hyperinflation in supine posture are influenced by EFL and gas trapping in COPD. Methods Clinically stable COPD patients (compatible symptoms, smoking >10 pack-years, obstructed spirometry) and healthy controls underwent oscillometry in the seated and supine positions. Hyperinflation was measured by inspiratory capacity (IC) and the ratio of IC to total lung capacity (IC/TLC) while seated and supine EFL was measured as the difference in mean inspiratory and mean expiratory oscillatory reactance at 5 Hz (Xrs5). Relationships between IC, IC/TLC and Xrs5, were examined by Spearman correlation. Results 42 COPD patients demonstrated no change in IC/TLC from seated (0.31 L) to supine (0.32 L) position (p=0.079) compared to significant increases seen in 14 control subjects (0.37 L seated versus 0.44 L supine; p<0.001). In COPD, worse dynamic elastance (Xrs5 rs 0.499; p=0.001) and EFL (ΔXrs5 rs −0.413; p=0.007), along with increased age and lower body-mass-index were predictors of supine hyperinflation. Conclusion Supine persistent hyperinflation occurs in COPD and is associated with increased dynamic elastance and EFL, likely the result of increased airway closure due to gravitational redistribution of lung mass.http://openres.ersjournals.com/content/10/6/00255-2024.full |
| spellingShingle | Meera Srinivasan Hannah Pollard David G. Chapman Katrina Tonga Kieran Patel Kaj Blokland David Touma Cindy Thamrin Troy Cross Kim Prisk Gregory G. King The effect of expiratory flow limitation on supine persistent hyperinflation in COPD: a prospective observational study ERJ Open Research |
| title | The effect of expiratory flow limitation on supine persistent hyperinflation in COPD: a prospective observational study |
| title_full | The effect of expiratory flow limitation on supine persistent hyperinflation in COPD: a prospective observational study |
| title_fullStr | The effect of expiratory flow limitation on supine persistent hyperinflation in COPD: a prospective observational study |
| title_full_unstemmed | The effect of expiratory flow limitation on supine persistent hyperinflation in COPD: a prospective observational study |
| title_short | The effect of expiratory flow limitation on supine persistent hyperinflation in COPD: a prospective observational study |
| title_sort | effect of expiratory flow limitation on supine persistent hyperinflation in copd a prospective observational study |
| url | http://openres.ersjournals.com/content/10/6/00255-2024.full |
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