Takatoshi Kasai1, Shveta S Motwani2, Rosilene M Elias1, Joseph M Gabriel2, Luigi Taranto Montemurro1, Naotake Yanagisawa3, Neil Spiller4, Narinder Paul4, T Douglas Bradley5. 1. Toronto Rehabilitation Institute, Toronto, Ontario, Canada ; Departments of Medicine of the Toronto General Hospital University Health Network, Toronto, Ontario, Canada. 2. Toronto Rehabilitation Institute, Toronto, Ontario, Canada. 3. Department of Cardiology, Juntendo University, School of Medicine, Tokyo, Japan. 4. Medical Imaging of the Toronto General Hospital University Health Network. 5. Toronto Rehabilitation Institute, Toronto, Ontario, Canada ; Departments of Medicine of the Toronto General Hospital University Health Network, Toronto, Ontario, Canada ; Centre for Sleep Medicine and Circadian Biology of the University of Toronto, Toronto, Ontario, Canada.
Abstract
STUDY OBJECTIVE: Fluid displacement from the legs during recumbency while in bed might narrow the upper airway (UA) in association with nuchal fluid accumulation that may contribute to the pathogenesis of obstructive sleep apnea (OSA). The aim of this study was to test the hypothesis that rostral fluid displacement from the legs causes a greater decrease in UA cross-sectional area (UA-XSA) and a greater increase in UA mucosal water content (UA-MWC) and internal jugular venous volume (IJVVol) in subjects with OSA than in those without OSA. METHODS: Subjects underwent baseline assessment of leg fluid volume (LFV) measured by bio-electrical impedance, as well as UA-XSA and UA-MWC by magnetic resonance imaging. They were then randomly assigned to a 20-min period either with or without application of lower body positive pressure (LBPP) of 40 mm Hg, followed by a 15-min washout period, after which they crossed over to the other arm of the study. Measurements of LFV, UA-MWC, and UA-XSA were repeated after each arm of the study. RESULTS: In 12 subjects without sleep apnea, UA-XSA increased and UA-MWC decreased significantly, whereas in 12 subjects with OSA, UA-XSA decreased and UA-MWC increased significantly in response to LBPP. The changes in UA-XSA and UA-MWC in response to LBPP differed significantly between the 2 groups (p = 0.006 and p < 0.001, respectively), despite similar changes in LFV and IJVVol. CONCLUSIONS: Our results suggest that rostral fluid shift may contribute to the pathogenesis of OSA at least partly through narrowing of the UA due to transudation of fluid into the UA mucosa.
RCT Entities:
STUDY OBJECTIVE: Fluid displacement from the legs during recumbency while in bed might narrow the upper airway (UA) in association with nuchal fluid accumulation that may contribute to the pathogenesis of obstructive sleep apnea (OSA). The aim of this study was to test the hypothesis that rostral fluid displacement from the legs causes a greater decrease in UA cross-sectional area (UA-XSA) and a greater increase in UA mucosal water content (UA-MWC) and internal jugular venous volume (IJVVol) in subjects with OSA than in those without OSA. METHODS: Subjects underwent baseline assessment of leg fluid volume (LFV) measured by bio-electrical impedance, as well as UA-XSA and UA-MWC by magnetic resonance imaging. They were then randomly assigned to a 20-min period either with or without application of lower body positive pressure (LBPP) of 40 mm Hg, followed by a 15-min washout period, after which they crossed over to the other arm of the study. Measurements of LFV, UA-MWC, and UA-XSA were repeated after each arm of the study. RESULTS: In 12 subjects without sleep apnea, UA-XSA increased and UA-MWC decreased significantly, whereas in 12 subjects with OSA, UA-XSA decreased and UA-MWC increased significantly in response to LBPP. The changes in UA-XSA and UA-MWC in response to LBPP differed significantly between the 2 groups (p = 0.006 and p < 0.001, respectively), despite similar changes in LFV and IJVVol. CONCLUSIONS: Our results suggest that rostral fluid shift may contribute to the pathogenesis of OSA at least partly through narrowing of the UA due to transudation of fluid into the UA mucosa.
Entities:
Keywords:
fluid displacement; lower body positive airway pressure; obstructive sleep apnea; upper airway cross-sectional area; upper airway mucosal water
Authors: Aviya Lanis; Eric Kerns; Susie L Hu; Margaret H Bublitz; Patricia Risica; Susan Martin; Jeffrey Parker; Richard Millman; Lance D Dworkin; Ghada Bourjeily Journal: Lung Date: 2018-05-26 Impact factor: 2.584