Pulmonary function with expiratory resistive loading in healthy volunteers.
Expiratory flow limitation is a key characteristic in obstructive pulmonary diseases. To study abnormal lung mechanics isolated from heterogeneities of obstructive disease, we measured pulmonary function in healthy adults with expiratory loading. Thirty-seven volunteers (25±5 yr) completed spirometr...
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Public Library of Science (PLoS)
2021-01-01
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| Series: | PLoS ONE |
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| author | Jyotika Erram Monica Bari Antoinette Domingo Daniel T Cannon |
| author_facet | Jyotika Erram Monica Bari Antoinette Domingo Daniel T Cannon |
| author_sort | Jyotika Erram |
| collection | DOAJ |
| description | Expiratory flow limitation is a key characteristic in obstructive pulmonary diseases. To study abnormal lung mechanics isolated from heterogeneities of obstructive disease, we measured pulmonary function in healthy adults with expiratory loading. Thirty-seven volunteers (25±5 yr) completed spirometry and body plethysmography under control and threshold expiratory loading of 7, 11 cmH2O, and a subset at 20 cmH2O (n = 11). We analyzed the shape of the flow-volume relationship with rectangular area ratio (RAR; Ma et al., Respir Med 2010). Airway resistance was increased (p<0.0001) with 7 and 11 cmH2O loading vs control (9.20±1.02 and 11.76±1.68 vs. 2.53± 0.80 cmH2O/L/s). RAR was reduced (p = 0.0319) in loading vs control (0.45±0.07 and 0.47±0.09L vs. 0.48±0.08). FEV1 was reduced (p<0.0001) in loading vs control (3.24±0.81 and 3.23±0.80 vs. 4.04±1.05 L). FVC was reduced (p<0.0001) in loading vs control (4.11±1.01 and 4.14±1.03 vs. 5.03±1.34 L). Peak expiratory flow (PEF) was reduced (p<0.0001) in loading vs control (6.03±1.67 and 6.02±1.84 vs. 8.50±2.81 L/s). FEV1/FVC (p<0.0068) was not clinically significant and FRC (p = 0.4) was not different in loading vs control. Supra-physiologic loading at 20 cmH2O did not result in further limitation. Expiratory loading reduced FEV1, FVC, PEF, but there were no clinically meaningful differences in FEV1/FVC, FRC, or RAR. Imposed expiratory loading likely leads to high airway pressures that resist dynamic airway compression. Thus, a concave expiratory flow-volume relationship was consistently absent-a key limitation for model comparison with pulmonary function in COPD. Threshold loading may be a useful strategy to increase work of breathing or induce dynamic hyperinflation. |
| format | Article |
| id | doaj-art-5b29868a632a463eb36b5cd92c27bd2e |
| institution | DOAJ |
| issn | 1932-6203 |
| language | English |
| publishDate | 2021-01-01 |
| publisher | Public Library of Science (PLoS) |
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| spelling | doaj-art-5b29868a632a463eb36b5cd92c27bd2e2025-08-20T03:00:49ZengPublic Library of Science (PLoS)PLoS ONE1932-62032021-01-01166e025291610.1371/journal.pone.0252916Pulmonary function with expiratory resistive loading in healthy volunteers.Jyotika ErramMonica BariAntoinette DomingoDaniel T CannonExpiratory flow limitation is a key characteristic in obstructive pulmonary diseases. To study abnormal lung mechanics isolated from heterogeneities of obstructive disease, we measured pulmonary function in healthy adults with expiratory loading. Thirty-seven volunteers (25±5 yr) completed spirometry and body plethysmography under control and threshold expiratory loading of 7, 11 cmH2O, and a subset at 20 cmH2O (n = 11). We analyzed the shape of the flow-volume relationship with rectangular area ratio (RAR; Ma et al., Respir Med 2010). Airway resistance was increased (p<0.0001) with 7 and 11 cmH2O loading vs control (9.20±1.02 and 11.76±1.68 vs. 2.53± 0.80 cmH2O/L/s). RAR was reduced (p = 0.0319) in loading vs control (0.45±0.07 and 0.47±0.09L vs. 0.48±0.08). FEV1 was reduced (p<0.0001) in loading vs control (3.24±0.81 and 3.23±0.80 vs. 4.04±1.05 L). FVC was reduced (p<0.0001) in loading vs control (4.11±1.01 and 4.14±1.03 vs. 5.03±1.34 L). Peak expiratory flow (PEF) was reduced (p<0.0001) in loading vs control (6.03±1.67 and 6.02±1.84 vs. 8.50±2.81 L/s). FEV1/FVC (p<0.0068) was not clinically significant and FRC (p = 0.4) was not different in loading vs control. Supra-physiologic loading at 20 cmH2O did not result in further limitation. Expiratory loading reduced FEV1, FVC, PEF, but there were no clinically meaningful differences in FEV1/FVC, FRC, or RAR. Imposed expiratory loading likely leads to high airway pressures that resist dynamic airway compression. Thus, a concave expiratory flow-volume relationship was consistently absent-a key limitation for model comparison with pulmonary function in COPD. Threshold loading may be a useful strategy to increase work of breathing or induce dynamic hyperinflation.https://journals.plos.org/plosone/article/file?id=10.1371/journal.pone.0252916&type=printable |
| spellingShingle | Jyotika Erram Monica Bari Antoinette Domingo Daniel T Cannon Pulmonary function with expiratory resistive loading in healthy volunteers. PLoS ONE |
| title | Pulmonary function with expiratory resistive loading in healthy volunteers. |
| title_full | Pulmonary function with expiratory resistive loading in healthy volunteers. |
| title_fullStr | Pulmonary function with expiratory resistive loading in healthy volunteers. |
| title_full_unstemmed | Pulmonary function with expiratory resistive loading in healthy volunteers. |
| title_short | Pulmonary function with expiratory resistive loading in healthy volunteers. |
| title_sort | pulmonary function with expiratory resistive loading in healthy volunteers |
| url | https://journals.plos.org/plosone/article/file?id=10.1371/journal.pone.0252916&type=printable |
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