Beyond the Larynx: New Insights Into Upper Airway Responses to Mechanical Insufflation-Exsufflation

This case report describes a 44-year-old man with amyotrophic lateral sclerosis (ALS) and ineffective secretion clearance despite home use of mechanical insufflation-exsufflation (MI-E). He reported upper airway obstruction, respiratory discomfort and recurrent aerophagia during therapy. Dynamic assessments using transnasal flexible laryngoscopy and videofluoroscopy under different MI-E settings showed that upper airway responses were strongly influenced by inspiratory flow, pressure levels, expiratory time and cervical positioning. Higher inspiratory flow and pressure induced supraglottic closure and airflow diversion to the oesophagus. In contrast, lower inspiratory flow combined with reduced expiratory pressure and shorter expiratory time improved glottic opening, maintained airway patency and enhanced cough mechanics. Spontaneously adopted cervical extension optimized airflow and minimized oesophageal insufflation, whereas neutral alignment impaired cough efficiency. These findings emphasize the importance of individualized MI-E settings and patient-specific biomechanics in optimizing therapy in ALS.