Laryngeal Responses During Non-Invasive Ventilation in Stable Chronic Obstructive Pulmonary Disease: An Observational...

Long-term non-invasive ventilation (NIV) is an established therapy for hypercapnic chronic obstructive pulmonary disease (COPD); however, many patients remain challenging to ventilate effectively. We hypothesized that NIV-induced laryngeal obstruction (NIV-ILO), observed during laryngoscopy, may contribute to reduced ventilatory effectiveness, and that this obstruction can be identified using laryngeal ultrasound (US).

This exploratory cross-sectional study included 15 participants with stable COPD receiving long-term NIV. Laryngeal responses were assessed using transnasal flexible laryngoscopy (TFL) and US. Assessments began during spontaneous breathing, followed by NIV at each participant's prescribed settings. Inspiratory positive airway pressure (IPAP) was increased in 2 cmH₂O increments to the device's maximum. Laryngeal responses were assessed in real time and reassessed retrospectively from video recordings. The participants rated discomfort using a numeric rating scale (0-10).

Fifteen participants (40% female) were included. The prescribed IPAP ranged from 7 to 30 cmH₂O, with NIV-ILO observed in 5 of 15 participants at a median of 22.0 cmH₂O. During subsequent pressure increments, additional 6 of 15 developed NIV-ILO at a median (range) IPAP of 20.5 cmH₂O (16.0-30.0), yielding 11 participants (73.3%) developing NIV-ILO within the pressure range of their device. US was assessable in 11 participants, with the structures of interest visualized during 54 of 63 pressure increments. The two methods demonstrated complete concordance for all assessable findings.

NIV-ILO was common in patients with COPD using long-term NIV, occurring within the pressure range typically applied to achieve effective ventilation. US can serve as a less invasive diagnostic alternative to TFL.