Background Most patients with amyotrophic lateral sclerosis (ALS) are treated with mechanical insufflation–exsufflation (MI-E) in order to improve cough. This method often fails in ALS with bulbar involvement, allegedly due to upper-airway malfunction. We have studied this phenomenon in detail with laryngoscopy to unravel information that could lead to better treatment.
Methods We conducted a cross-sectional study of 20 patients with ALS and 20 healthy age-matched and sex-matched volunteers. We used video-recorded flexible transnasal fibre-optic laryngoscopy during MI-E undertaken according to a standardised protocol, applying pressures of ±20 to ±50 cm H2O. Laryngeal movements were assessed from video files. ALS type and characteristics of upper and lower motor neuron symptoms were determined.
Results At the supraglottic level, all patients with ALS and bulbar symptoms (n=14) adducted their laryngeal structures during insufflation. At the glottic level, initial abduction followed by subsequent adduction was observed in all patients with ALS during insufflation and exsufflation. Hypopharyngeal constriction during exsufflation was observed in all subjects, most prominently in patients with ALS and bulbar symptoms. Healthy subjects and patients with ALS and no bulbar symptoms (n=6) coordinated their cough well during MI-E.
Conclusions Laryngoscopy during ongoing MI-E in patients with ALS and bulbar symptoms revealed laryngeal adduction especially during insufflation but also during exsufflation, thereby severely compromising the size of the laryngeal inlet in some patients. Individually customised settings can prevent this and thereby improve and extend the use of non-invasive MI-E.
- Non invasive ventilation
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Contributors All authors made a significant contribution to the conception and the design of the article and of the collection, analysis and interpretation of the data, drafting of the article and revising it critically for content and final approval of the version to be published. All authors participate in the research group and are collectively responsible for the final version of this paper.
Funding The Norwegian Centre of Excellence for Home Mechanical Ventilation, Thoracic Department, Haukeland University Hospital, Bergen, Norway and Western Norway Regional Health Authority funded this study.
Competing interests TA has received honoraria of €500 for a lecture in an international conference sponsored by Respironics. Sponsors were not involved and had no impact on the study design, in the collection, analysis and interpretation of data, in writing of the report, nor in the decision to submit the article for publication.
Patient consent Obtained.
Ethics approval Regional Committee for Medical Research Ethics, Western Norway Regional Health Authority, Bergen, Norway.
Provenance and peer review Not commissioned; externally peer reviewed.
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