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Published on: February 2, 2024
Overnight variation in tidal expiratory flow limitation in COPD patients and its correction: an observational study
J McKenzie1, P Nisha1, S Cannon-Bailey1
1Philips Respironics, Monroeville, PA, USA.
Background:
Tidal expiratory flow limitation (EFLT) is common among COPD patients. Whether EFLT changes during sleep and can be abolished during home ventilation is not known.
Methods:
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 EFLT. Participants flow limited (∆Xrs > 2.8) when supine underwent polysomnography (PSG) and were offered home ventilation for 2 weeks. The EPAP pressure that abolished EFLT was measured and compared to that during supine wakefulness. Ventilator adherence and subjective patient perceptions were obtained after home use.
Results:
Of 26 patients with supine EFLT, 15 completed overnight PSG and 10 the home study. In single night and 2-week home studies, EFLT 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 cmH2O of the awake screening pressure. Over 2 weeks, mean EPAP was almost half the mean maximum EPAP (11.7 vs 6.4 cmH2O respectively). Group mean ∆Xrs was ≤ 2.8 for 77.3% of their home use with a mean time to abolish new EFLT 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.
Conclusions:
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.
Trial Registration:
The trial was retrospectively registered at CT.gov NCT04725500.
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