TY - JOUR
T1 - Respiratory-related displacement of the trachea in obstructive sleep apnea
AU - Tong, Joshua
AU - Juge, Lauriane
AU - Burke, Peter G.R.
AU - Knapman, Fiona
AU - Eckert, Danny J.
AU - Bilston, Lynne E.
AU - Amatoury, Jason
PY - 2019/1/1
Y1 - 2019/1/1
N2 - Tracheal displacement is thought to be the primary mechanism by which changes in lung volume influence upper airway patency. Caudal tracheal displacement during inspiration may help preserve the integrity of the upper airway in response to increasing negative airway pressure by stretching and stiffening pharyngeal tissues. However, tracheal displacement has not been previously quantified in obstructive sleep apnea (OSA). Accordingly, we aimed to measure tracheal displacements in awake individuals with and without OSA. The upper head and neck of 34 participants [apneahypopnea index (AHI) = 2-74 events/h] were imaged in the midsagittal plane using dynamic magnetic resonance imaging (MRI) during supine awake quiet breathing. MRI data were analyzed to identify peak tracheal displacement and its timing relative to inspiration. Epiglottic pressure was measured separately for a subset of participants (n = 30) during similar experimental conditions. Nadir epiglottic pressure and its timing relative to inspiration were quantified. Peak tracheal displacement ranged from 1.0-9.6 mm, with a median (25th-75th percentile) of 2.3 (1.7-3.5) mm, and occurred at 89 (78-99)% of inspiratory time. Peak tracheal displacement increased with increasing OSA severity (AHI) (R2 = 0.28, P = 0.013) and increasing negative nadir epiglottic pressure (R2 = 0.47, P = 0.023). Relative inspiratory timing of peak tracheal displacement also correlated with OSA severity, with peak displacement occurring earlier in inspiration with increasing AHI (R2 = 0.36, P = 0.002). Tracheal displacements during quiet breathing are larger in individuals with more severe OSA and tend to reach peak displacement earlier in the inspiratory cycle. Increased tracheal displacement may contribute to maintenance of upper airway patency during wakefulness in OSA, particularly in those with severe disease. NEW & NOTEWORTHY Tracheal displacement is thought to play an important role in stabilizing the upper airway by stretching/stiffening the pharyngeal musculature. Using dynamic magnetic resonance imaging, this study shows that caudal tracheal displacement is more pronounced during inspiration in obstructive sleep apnea (OSA) compared with healthy individuals. Softer pharyngeal muscles and greater inspiratory forces in OSA may underpin greater tracheal excursion. These findings suggest that tracheal displacement may contribute to maintenance of pharyngeal patency during wakefulness in OSA.
AB - Tracheal displacement is thought to be the primary mechanism by which changes in lung volume influence upper airway patency. Caudal tracheal displacement during inspiration may help preserve the integrity of the upper airway in response to increasing negative airway pressure by stretching and stiffening pharyngeal tissues. However, tracheal displacement has not been previously quantified in obstructive sleep apnea (OSA). Accordingly, we aimed to measure tracheal displacements in awake individuals with and without OSA. The upper head and neck of 34 participants [apneahypopnea index (AHI) = 2-74 events/h] were imaged in the midsagittal plane using dynamic magnetic resonance imaging (MRI) during supine awake quiet breathing. MRI data were analyzed to identify peak tracheal displacement and its timing relative to inspiration. Epiglottic pressure was measured separately for a subset of participants (n = 30) during similar experimental conditions. Nadir epiglottic pressure and its timing relative to inspiration were quantified. Peak tracheal displacement ranged from 1.0-9.6 mm, with a median (25th-75th percentile) of 2.3 (1.7-3.5) mm, and occurred at 89 (78-99)% of inspiratory time. Peak tracheal displacement increased with increasing OSA severity (AHI) (R2 = 0.28, P = 0.013) and increasing negative nadir epiglottic pressure (R2 = 0.47, P = 0.023). Relative inspiratory timing of peak tracheal displacement also correlated with OSA severity, with peak displacement occurring earlier in inspiration with increasing AHI (R2 = 0.36, P = 0.002). Tracheal displacements during quiet breathing are larger in individuals with more severe OSA and tend to reach peak displacement earlier in the inspiratory cycle. Increased tracheal displacement may contribute to maintenance of upper airway patency during wakefulness in OSA, particularly in those with severe disease. NEW & NOTEWORTHY Tracheal displacement is thought to play an important role in stabilizing the upper airway by stretching/stiffening the pharyngeal musculature. Using dynamic magnetic resonance imaging, this study shows that caudal tracheal displacement is more pronounced during inspiration in obstructive sleep apnea (OSA) compared with healthy individuals. Softer pharyngeal muscles and greater inspiratory forces in OSA may underpin greater tracheal excursion. These findings suggest that tracheal displacement may contribute to maintenance of pharyngeal patency during wakefulness in OSA.
KW - Lung volume
KW - Magnetic resonance imaging (MRI)
KW - Pharyngeal pressure
KW - Sleep-disordered breathing
KW - Tracheal traction
UR - http://www.scopus.com/inward/record.url?scp=85074746479&partnerID=8YFLogxK
UR - http://purl.org/au-research/grants/nhmrc/1058974
UR - http://purl.org/au-research/grants/nhmrc/1077934
UR - http://purl.org/au-research/grants/nhmrc/1116942
UR - http://purl.org/au-research/grants/nhmrc/1060992
U2 - 10.1152/japplphysiol.00660.2018
DO - 10.1152/japplphysiol.00660.2018
M3 - Article
C2 - 31513451
AN - SCOPUS:85074746479
SN - 8750-7587
VL - 127
SP - 1307
EP - 1316
JO - Journal of Applied Physiology
JF - Journal of Applied Physiology
IS - 5
ER -