Airway dynamics in COPD patients by within-breath impedance tracking: effects of continuous positive airway pressure

Lorx, András, Czovek, Dorottya, Gingl, Zoltán, Makan, Gergely, Radics, Bence, Bartusek, Dóra, Szigeti, Szabolcs, Gal, János, Losonczy, György, Sly, Peter D. and Hantos, Zoltán (2017) Airway dynamics in COPD patients by within-breath impedance tracking: effects of continuous positive airway pressure. European Respiratory Journal, 49 2: . doi:10.1183/13993003.01270-2016


Author Lorx, András
Czovek, Dorottya
Gingl, Zoltán
Makan, Gergely
Radics, Bence
Bartusek, Dóra
Szigeti, Szabolcs
Gal, János
Losonczy, György
Sly, Peter D.
Hantos, Zoltán
Title Airway dynamics in COPD patients by within-breath impedance tracking: effects of continuous positive airway pressure
Journal name European Respiratory Journal   Check publisher's open access policy
ISSN 1399-3003
0903-1936
Publication date 2017-02-01
Year available 2017
Sub-type Article (original research)
DOI 10.1183/13993003.01270-2016
Open Access Status Not yet assessed
Volume 49
Issue 2
Total pages 11
Place of publication Lausanne, Switzerland
Publisher European Respiratory Society
Language eng
Subject 2740 Pulmonary and Respiratory Medicine
Abstract Tracking of the within-breath changes of respiratory mechanics using the forced oscillation technique may provide outcomes that characterise the dynamic behaviour of the airways during normal breathing. We measured respiratory resistance (Rrs) and reactance (Xrs) at 8 Hz in 55 chronic obstructive pulmonary disease (COPD) patients and 20 healthy controls, and evaluated Rrs and Xrs as functions of gas flow (V′) and volume (V) during normal breathing cycles. In 12 COPD patients, additional measurements were made at continuous positive airway pressure (CPAP) levels of 4, 8, 14 and 20 hPa. The Rrs and Xrs versus V′ and V relationships displayed a variety of loop patterns, allowing characterisation of physiological and pathological processes. The main outcomes emerging from the within-breath analysis were the Xrs versus V loop area (AXV) quantifying expiratory flow limitation, and the tidal change in Xrs during inspiration (ΔXI) reflecting alteration in lung inhomogeneity in COPD. With increasing CPAP, AXV and ΔXI approached the normal ranges, although with a large variability between individuals, whereas mean Rrs remained unchanged. Within-breath tracking of Rrs and Xrs allows an improved assessment of expiratory flow limitation and functional inhomogeneity in COPD; thereby it may help identify the physiological phenotypes of COPD and determine the optimal level of respiratory support.
Formatted abstract
Tracking of the within-breath changes of respiratory mechanics using the forced oscillation technique may provide outcomes that characterise the dynamic behaviour of the airways during normal breathing. We measured respiratory resistance (Rrs) and reactance (Xrs) at 8 Hz in 55 chronic obstructive pulmonary disease (COPD) patients and 20 healthy controls, and evaluated Rrs and Xrs as functions of gas flow (V′) and volume (V) during normal breathing cycles. In 12 COPD patients, additional measurements were made at continuous positive airway pressure (CPAP) levels of 4, 8, 14 and 20 hPa. The Rrs and Xrs versus V′ and V relationships displayed a variety of loop patterns, allowing characterisation of physiological and pathological processes. The main outcomes emerging from the within-breath analysis were the Xrs versus V loop area (AXV) quantifying expiratory flow limitation, and the tidal change in Xrs during inspiration (ΔXI) reflecting alteration in lung inhomogeneity in COPD. With increasing CPAP, AXV and ΔXI approached the normal ranges, although with a large variability between individuals, whereas mean Rrs remained unchanged. Within-breath tracking of Rrs and Xrs allows an improved assessment of expiratory flow limitation and functional inhomogeneity in COPD; thereby it may help identify the physiological phenotypes of COPD and determine the optimal level of respiratory support.
Keyword Respiratory System
Respiratory System
Q-Index Code C1
Q-Index Status Provisional Code
Grant ID 105403
1002035
Institutional Status UQ

Document type: Journal Article
Sub-type: Article (original research)
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