Midtveisevaluering - Tiina Andersen
Background Most patients with amyotrophic lateral sclerosis (ALS) are treated with mechanical cough assist devices using the technique of mechanical insufflation-exsufflation (MI-E) in order to improve cough and prevent lung infections. The technique often fails in ALS patients with bulbar involvement, allegedly due to upper airway malfunction. Laryngeal collapse during exsufflation has been proposed to explain the ineffectiveness of MI-E in bulbar ALS.
Objectives We have studied laryngeal response patterns during MI-E in detail with laryngoscopy, aiming to unravel information that could lead to better treatment.
Methods In the first study, 20 healthy medical students were examined to determine if the method of laryngoscopy is useful to reveal laryngeal responses to MI-E. In the second study , 20 patients with ALS and 20 healthy age and gender matched volunteers were examined. Video recorded flexible transnasal fiberoptic laryngoscopy was used during ongoing MI-E, performed according to a standardized protocol applying pressures of ±20 to ±50 cmH2O. Laryngeal movements were retrospectively assessed from video files. The subclass of ALS and the presence of upper and lower motor neuron symptom characteristics were determined.
First results 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 in patients with ALS.