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


METHODS
Twenty 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.


RESULTS
An 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.


CONCLUSIONS
The 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.
From the Thoracic Department, Norwegian Centre of Excellence for Home Mechanical Ventilation (TA, OF), Department of Physiotherapy (TA), Department of Pediatrics (AS, TH, ODR), Department of Otolaryngology/Head and Neck Surgery (MH, J-HH), and Department of Neurology (O-BT), Haukeland University Hospital, Bergen, Norway; Institute of Clinical Medicine (TH, ODR) and Institute of Surgical Science (J-HH), University of Bergen, Bergen, Norway; and Bergen University College, Bergen, Norway (TA, ODR).
Tiina
T
Andersen
Astrid
A
Sandnes
Magnus
M
Hilland
Thomas
T
Halvorsen
Ove
O
Fondenes
John-Helge
JH
Heimdal
Ole-Bjørn
OB
Tysnes
Ola Drange
OD
Røksund
D000328:Adult; D003371:Cough; D003430:Cross-Sectional Studies; D005260:Female; D006801:Humans; D007327:Insufflation / Q000295:instrumentation; D007828:Laryngoscopy; D007830:Larynx / Q000502:physiology*; D008297:Male; D012123:Pulmonary Ventilation / Q000502:physiology; D013147:Spirometry; D014741:Video Recording; D055815:Young Adult