Relationships between forced oscillatory impedance and 6-minute walk distance after pulmonary rehabilitation in COPD

Zimmermann, SC; Thamrin, C; Chan, ASL; Bertolin, A; Chapman, DG; King, GG

Relationships between forced oscillatory impedance and 6-minute walk distance after pulmonary rehabilitation in COPD

Zimmermann, SC Thamrin, C Chan, ASL Bertolin, A Chapman, DG

King, GG

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Publication Type:: Journal Article
Citation:: International Journal of COPD, 2020, 15 pp. 157 - 166
Issue Date:: 2020-01-01

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Field	Value	Language
dc.contributor.author	Zimmermann, SC	en_US
dc.contributor.author	Thamrin, C	en_US
dc.contributor.author	Chan, ASL	en_US
dc.contributor.author	Bertolin, A	en_US
dc.contributor.author	Chapman, DG https://orcid.org/0000-0002-8211-1817	en_US
dc.contributor.author	King, GG	en_US
dc.date.accessioned	2020-04-14T04:03:08Z
dc.date.available	2019-12-19	en_US
dc.date.available	2020-04-14T04:03:08Z
dc.date.issued	2020-01-01	en_US
dc.identifier.citation	International Journal of COPD, 2020, 15 pp. 157 - 166	en_US
dc.identifier.issn	1176-9106	en_US
dc.identifier.uri	http://hdl.handle.net/10453/139979
dc.description.abstract	© 2020 Zimmermann et al. Rationale: Pulmonary rehabilitation for chronic obstructive pulmonary disease (COPD) reduces dyspnoea and improves exercise capacity and quality of life. The improvement in exercise capacity is variable and unpredictable, however. Respiratory system impedance obtained by forced oscillation technique (FOT) as a measure of ventilatory impairment in COPD may relate to improvement in exercise capacity with pulmonary rehabilitation. We aimed to determine if baseline FOT parameters relate to changes in exercise capacity following pulmonary rehabilitation. Methods: At the start of rehabilitation, 15 COPD subjects (mean(SD) 75.2(6.1) years, FEV1 z-score −2.61(0.84)) had measurements by FOT, spirometry, plethysmographic lung volumes and 6-minute walk distance (6MWD). Respiratory system resistance (Rrs) and reactance (Xrs) parameters as the mean over all breaths (Rmean,Xmean), during inspiration only (Rinsp, Xinsp), and expiratory flow limitation (DeltaXrs = Xinsp−Xexp), were calculated. FOT and 6MWD measurements were repeated at completion of rehabilitation and 3 months after completion. Results: At baseline, Xrs measures were unrelated to 6MWD. Xinsp improved significantly with rehabilitation (from mean(SD) −2.35(1.02) to −2.04(0.85) cmH2O.s.L−1, p=0.008), while other FOT parameters did not. No FOT parameters related to the change in 6MWD at program completion. Baseline Xmean, DeltaXrs, and FVC z-score correlated with the change in 6MWD between completion and 3 months after completion of rehabilitation (rs =0.62, p=0.03; rs=−0.65, p=0.02; and rs=0.62, p=0.03, respectively); with worse ventilatory impairment predicting loss of 6MWD. There were no relationships between Rrs parameters, FEV1 or FEV1/FVC z-scores and changes in 6MWD. Conclusion: Baseline reactance parameters may be helpful in predicting those patients with COPD at most risk of loss of exercise capacity following completion of pulmonary rehabilitation.	en_US
dc.relation.ispartof	International Journal of COPD	en_US
dc.relation.isbasedon	10.2147/COPD.S225543	en_US
dc.subject.classification	Respiratory System	en_US
dc.title	Relationships between forced oscillatory impedance and 6-minute walk distance after pulmonary rehabilitation in COPD	en_US
dc.type	Journal Article
utslib.citation.volume	15	en_US
utslib.for	1102 Cardiorespiratory Medicine and Haematology	en_US
pubs.embargo.period	Not known	en_US
pubs.organisational-group	/University of Technology Sydney
pubs.organisational-group	/University of Technology Sydney/Faculty of Science
pubs.organisational-group	/University of Technology Sydney/Faculty of Science/School of Life Sciences
utslib.copyright.status	open_access
pubs.publication-status	Published	en_US
pubs.volume	15	en_US

Abstract:

© 2020 Zimmermann et al. Rationale: Pulmonary rehabilitation for chronic obstructive pulmonary disease (COPD) reduces dyspnoea and improves exercise capacity and quality of life. The improvement in exercise capacity is variable and unpredictable, however. Respiratory system impedance obtained by forced oscillation technique (FOT) as a measure of ventilatory impairment in COPD may relate to improvement in exercise capacity with pulmonary rehabilitation. We aimed to determine if baseline FOT parameters relate to changes in exercise capacity following pulmonary rehabilitation. Methods: At the start of rehabilitation, 15 COPD subjects (mean(SD) 75.2(6.1) years, FEV1 z-score −2.61(0.84)) had measurements by FOT, spirometry, plethysmographic lung volumes and 6-minute walk distance (6MWD). Respiratory system resistance (Rrs) and reactance (Xrs) parameters as the mean over all breaths (Rmean,Xmean), during inspiration only (Rinsp, Xinsp), and expiratory flow limitation (DeltaXrs = Xinsp−Xexp), were calculated. FOT and 6MWD measurements were repeated at completion of rehabilitation and 3 months after completion. Results: At baseline, Xrs measures were unrelated to 6MWD. Xinsp improved significantly with rehabilitation (from mean(SD) −2.35(1.02) to −2.04(0.85) cmH2O.s.L−1, p=0.008), while other FOT parameters did not. No FOT parameters related to the change in 6MWD at program completion. Baseline Xmean, DeltaXrs, and FVC z-score correlated with the change in 6MWD between completion and 3 months after completion of rehabilitation (rs =0.62, p=0.03; rs=−0.65, p=0.02; and rs=0.62, p=0.03, respectively); with worse ventilatory impairment predicting loss of 6MWD. There were no relationships between Rrs parameters, FEV1 or FEV1/FVC z-scores and changes in 6MWD. Conclusion: Baseline reactance parameters may be helpful in predicting those patients with COPD at most risk of loss of exercise capacity following completion of pulmonary rehabilitation.

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http://hdl.handle.net/10453/139979