Laryngoscopic assessment during non-invasive respiratory support in patients with neuromuscular disease: a...

Non-invasive ventilation (NIV) improves symptoms and survival in neuromuscular disease (NMD), but a subgroup of patients experience NIV intolerance, particularly those with bulbar involvement. Positive-pressure respiratory support may provoke dynamic laryngeal narrowing in susceptible individuals, a phenomenon termed ventilation-induced laryngeal obstruction (V-ILO). Continuous laryngoscopy during respiratory support may help identify V-ILO and guide optimisation of ventilator settings.

This single-centre observational service evaluation included consecutive patients with confirmed NMD who presented with upper-airway symptoms warranting endoscopic assessment. Continuous laryngoscopy was performed during NIV, mechanical insufflation-exsufflation (MI-E) or CPAP where symptoms suggested intolerance of positive-pressure respiratory support. Laryngeal behaviour, secretion burden and response to ventilator adjustments were assessed under direct visualisation.

Forty-nine patients were included; 48 underwent laryngoscopy. Twenty-one underwent continuous laryngoscopy during positive-pressure respiratory support because of NIV intolerance or related symptoms. Twelve demonstrated V-ILO, characterised by inappropriate dynamic glottic and/or supraglottic narrowing, predominantly during inspiration. Nine of these twelve patients were successfully established on NIV following laryngoscopy-guided optimisation, which involved identifying an initially tolerable level and pattern of support by adjusting inspiratory pressure and/or rise time under direct visualisation. Subsequent titration to therapeutic pressures was performed clinically, with no recurrence of clinically recognised V-ILO.

V-ILO represents a potentially reversible cause of NIV intolerance in patients with neuromuscular disease. Continuous laryngoscopy during respiratory support provides clinically useful information that can guide ventilator optimisation, improve tolerance of NIV and inform management of secretion burden and other laryngeal abnormalities. These findings support further evaluation of laryngoscopy-guided optimisation within specialist home mechanical ventilation services.