Overnight variation in tidal expiratory flow limitation in COPD patients and its correction: an observational study

McKenzie, J, Nisha, P, Cannon-Bailey, S, Cain, C, Kissel, M, Stachel, J, Proscyk, C, Romano, R, Hardy, B and Calverley, PMA (2021) Overnight variation in tidal expiratory flow limitation in COPD patients and its correction: an observational study. RESPIRATORY RESEARCH, 22 (1). 319-.

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Official URL: http://dx.doi.org/10.1186/s12931-021-01913-7

Abstract

<h4>Background</h4>Tidal expiratory flow limitation (EFL<sub>T</sub>) is common among COPD patients. Whether EFL<sub>T</sub> changes during sleep and can be abolished during home ventilation is not known.<h4>Methods</h4>COPD patients considered for noninvasive ventilation used a ventilator which measured within-breath reactance change at 5 Hz (∆Xrs) and adjusted EPAP settings to abolish EFL<sub>T</sub>. Participants flow limited (∆Xrs > 2.8) when supine underwent polysomnography (PSG) and were offered home ventilation for 2 weeks. The EPAP pressure that abolished EFL<sub>T</sub> was measured and compared to that during supine wakefulness. Ventilator adherence and subjective patient perceptions were obtained after home use.<h4>Results</h4>Of 26 patients with supine EFL<sub>T</sub>, 15 completed overnight PSG and 10 the home study. In single night and 2-week home studies, EFL<sub>T</sub> within and between participants was highly variable. This was unrelated to sleep stage or body position with only 14.6% of sleep time spent within 1 cmH<sub>2</sub>O of the awake screening pressure. Over 2 weeks, mean EPAP was almost half the mean maximum EPAP (11.7 vs 6.4 cmH<sub>2</sub>O respectively). Group mean ∆Xrs was ≤ 2.8 for 77.3% of their home use with a mean time to abolish new EFL<sub>T</sub> of 5.91 min. Adherence to the ventilator varied between 71 and 100% in prior NIV users and 36-100% for naïve users with most users rating therapy as comfortable.<h4>Conclusions</h4>Tidal expiratory flow limitation varies significant during sleep in COPD patients. This can be controlled by auto-titrating the amount of EPAP delivered. This approach appears to be practical and well tolerated by patients.<h4>Trial registration</h4>The trial was retrospectively registered at CT.gov NCT04725500.

Item Type:	Article
Uncontrolled Keywords:	COPD, Noninvasive ventilation (NIV), Tidal expiratory flow limitation (EFLT), Forced oscillation technique, Expiratory positive airway pressure (EPAP)
Divisions:	Faculty of Health and Life Sciences Faculty of Health and Life Sciences > Institute of Life Courses and Medical Sciences
Depositing User:	Symplectic Admin
Date Deposited:	18 May 2022 14:02
Last Modified:	18 Jan 2023 21:01
DOI:	10.1186/s12931-021-01913-7
Open Access URL:	https://respiratory-research.biomedcentral.com/art...
Related URLs:	Author Publisher
URI:	https://livrepository.liverpool.ac.uk/id/eprint/3155061