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Laryngeal Movements During the Respiratory Cycle Measured with an Endoscopic Imaging Technique in the Conscious Horse at Rest
Author(s) -
Lafortuna Claudio L.,
Albertini Mariangela,
Ferrucci Francesco,
Zucca Enrica,
Braghieri Martina,
Clement M. Giovanna,
Saibene Franco
Publication year - 1999
Publication title -
experimental physiology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.925
H-Index - 101
eISSN - 1469-445X
pISSN - 0958-0670
DOI - 10.1111/j.1469-445x.1999.01851.x
Subject(s) - expiration , larynx , respiratory system , respiratory tract , medicine , airflow , breathing , airway , rest (music) , horse , anatomy , anesthesia , nuclear medicine , biomedical engineering , cardiology , physics , biology , paleontology , thermodynamics
SUMMARY A video‐laryngoscopic method, implemented with an algorithm for the correction of the deformation inherent in the endoscope optical system, has been used to measure the dorsoventral diameter ( D rg ) and the cross‐sectional area (CSA rg ) of the rima glottidis in five healthy workhorses during conscious breathing at rest. Simultaneous recording of the respiratory airflow was also obtained in two horses. D rg measured 82·7 ± 4·5 mm (mean ± s.d. ) independently of the respiratory phase, and did not differ from the measurement in post‐mortem anatomical specimens of the same horses. CSA rg ranged from 1130 ± 117 mm 2 (mean ± s.d. ) during the inspiratory phase to 640 ± 242 mm 2 during the expiratory phase, being always narrower than tracheal cross‐sectional area, which was 1616 ± 224 mm 2 , as determined from anatomical specimens. Both inspiratory and expiratory airflow waves displayed a biphasic pattern. Maximal laryngeal opening occurred in phase with the second inspiratory peak, while during expiration CSA rg attained a minimum value during the first expiratory peak which was significantly smaller ( P < 0·01) than the area subsequently maintained during the rest of the expiratiory phase. These quantitative measurements of equine laryngeal movements substantiate the important role played by the larynx in regulating upper airway respiratory resistance and the expiratory airflow pattern at rest.