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

Background: Tidal expiratory flow limitation (EFL) is common among COPD patients. Whether EFL 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 EFL.