Tiina Andersen

Laryngeal response patterns influence the efficacy of mechanical assisted cough in amyotrophic lateral sclerosis

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.

Laryngeal response patterns to mechanical insufflation-exsufflation in healthy subjects.

ObjectiveMechanical insufflation-exsufflation (MI-E) is used to assist cough in patients with neuromuscular diseases. Clinically, application may be challenging in some patient groups, possibly related to laryngeal dysfunction. Before launching a study in patients, the authors investigated laryngeal responses to MI-E in healthy individuals. DesignTwenty healthy volunteers, aged 21–29 yrs, were studied with video-recorded flexible transnasal fiber-optic laryngoscopy while performing MI-E using the Cough Assist (Respironics, United States) according to a standardized protocol applying pressures of ±20 to ±50 cm H2O. ResultsAn initial abduction of the vocal folds was observed in all subjects, both during the insufflation and exsufflation phases. Nineteen of the 20 subjects adequately coordinated glottic closure when instructed to cough. When instructed simply to exhale during exsufflation, the glottis stayed open in a majority. Subsequent to an initial abduction during exsufflation and cough, various obstructive laryngeal movements were observed in some subjects, such as narrowing of the vocal folds, retroflexion of the epiglottis, hypopharyngeal constriction, and backward movement of the base of the tongue. ConclusionsThe larynx can be studied with transnasal laryngoscopy during MI-E in healthy individuals. Laryngeal responses to MI-E vary, and laryngoscopy may offer valuable clinical information when applying MI-E in patients with bulbar muscle weakness.

Airway clearance techniques in neuromuscular disorders: A state of the art review

This is a unique state of the art review written by a group of 21 international recognized experts in the field that gathered during a meeting organized by the European Neuromuscular Centre (ENMC) in Naarden, March 2017. It systematically reports the entire evidence base for airway clearance techniques (ACTs) in both adults and children with neuromuscular disorders (NMD). We not only report randomised controlled trials, which in other systematic reviews conclude that there is a lack of evidence base to give an opinion, but also include case series and retrospective reviews of practice. For this review, we have classified ACTs as either proximal (cough augmentation) or peripheral (secretion mobilization). The review presents descriptions; standard definitions; the supporting evidence for and limitations of proximal and peripheral ACTs that are used in patients with NMD; as well as providing recommendations for objective measurements of efficacy, specifically for proximal ACTs. This state of the art review also highlights how ACTs may be adapted or modified for specific contexts (e.g. in people with bulbar insufficiency; children and infants) and recommends when and how each technique should be applied.

Laryngeal Responses to Mechanically Assisted Cough in Progressing Amyotrophic Lateral Sclerosis

BACKGROUND: Respiratory complications represent the major cause of death in amyotrophic lateral sclerosis (ALS). Noninvasive respiratory support is the mainstay therapy, but treatment becomes challenging as the disease progresses, possibly due to a malfunctioning larynx, which is the entrance to the airways. We studied laryngeal response patterns to mechanically assisted cough (mechanical insufflation-exsufflation) as ALS progresses. METHODS: This prospective longitudinal study of 13 consecutively included subjects with ALS were followed up during 2011–2016 with repeated tests of lung function, neurological status, and laryngeal responses to mechanical insufflation-exsufflation using video-recorded flexible transnasal fiberoptic laryngoscopy. RESULTS: Follow-up time was median 17 (range 6–59) months. In total, 751 laryngoscopy recordings from 67 individual examinations (median 4 per subject, range 2–11 per subject) were analyzed. Adverse laryngeal events that developed with disease progression during insufflation included adduction of true vocal folds in 8 of 9 spinal-onset subjects and adduction of aryepiglottic folds in all subjects, initially at the highest positive pressure and prior to onset of other bulbar symptoms in spinal-onset subjects. As cough became less expulsive with disease progression, laryngeal adduction occurred at lower insufflation pressures. Retroflex movement of the epiglottis was observed in 7 of 13 subjects regardless of insufflation pressures and independent of bulbar involvements. Backward movement of the tongue base occurred regardless of insufflation pressures in all but 1 subject. During exsufflation, constriction of the hypopharynx was observed in all subjects regardless of the presence of bulbar symptoms, after the adverse events that occurred during insufflation. CONCLUSIONS: Applying high insufflation pressures during mechanically assisted cough in ALS can become counterproductive as the disease progresses; importantly also prior to the onset of bulbar symptoms. The application of positive inspiratory pressures should be tailored to the individual patient, and laryngoscopy during ongoing treatment appears to be a feasible tool.

The clinical use of mechanical insufflation-exsufflation in children with neuromuscular disorders in Europe

Mechanical insufflation-exsufflation (MI-E) is a strategy to treat pulmonary exacerbations in neuromuscular disorders (NMDs). Pediatric guidelines for optimal setting titration of MI-E are lacking and the settings used in studies vary. Our objective was to assess the actual MI-E settings being used in current clinical treatment of children with NMDs and a survey was sent in July 2016 to European expertise centers. Ten centers from seven countries gave information on MI-E settings for 240 children aged 4 months to 17.8 years (mean 10.5). Settings varied greatly between the centers. Auto mode was used in 71%, triggering of insufflation in 21% and manual mode in 8% of the cases. Mean (SD) time for insufflation (Ti) and exsufflation (Te) were 1.9 (0.5) and 1.8 (0.6) s respectively, both ranging from 1 to 4s. Asymmetric time settings were common (65%). Mean (SD) insufflation (Pi) and exsufflation (Pe) pressures were 32.4 (7.8) and -36.9 (7.4), ranging 10 to 50 and -10 to -60cmH2O, respectively. Asymmetric pressures were as common as symmetric. Both Ti, Te, Pi and Pe increased with age (p < 0.001). In conclusion, pediatric MI-E settings in clinical use varied greatly and altered with age, highlighting the need of more studies to improve our knowledge of optimal settings in MI-E in children with NMDs.