Kasai Takatoshi, Motwani Shveta S, Elias Rosilene M, Gabriel Joseph M, Taranto Montemurro Luigi, Yanagisawa Naotake, Spiller Neil, Paul Narinder, Bradley T Douglas
Toronto Rehabilitation Institute, Toronto, Ontario, Canada ; Departments of Medicine of the Toronto General Hospital University Health Network, Toronto, Ontario, Canada.
Toronto Rehabilitation Institute, Toronto, Ontario, Canada.
J Clin Sleep Med. 2014 Oct 15;10(10):1069-74. doi: 10.5664/jcsm.4102.
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.
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.
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.
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.
卧床时腿部卧位液体移位可能会使上气道（UA）变窄，同时伴有颈部液体蓄积，这可能会导致阻塞性睡眠呼吸暂停（OSA）的发病机制。本研究的目的是检验这一假设：与无OSA的受试者相比，腿部向头侧的液体移位会导致OSA受试者的UA横截面积（UA-XSA）下降幅度更大，UA黏膜含水量（UA-MWC）和颈内静脉容量（IJVVol）增加幅度更大。
受试者接受通过生物电阻抗测量腿部液体量（LFV）的基线评估，以及通过磁共振成像测量UA-XSA和UA-MWC。然后将他们随机分为两组，一组施加40 mmHg的下体正压（LBPP）20分钟，另一组不施加LBPP，之后有15分钟的洗脱期，然后两组交叉进行另一组的研究。在研究的每个阶段后重复测量LFV、UA-MWC和UA-XSA。
在12名无睡眠呼吸暂停的受试者中，UA-XSA增加，UA-MWC显著下降；而在12名OSA受试者中，响应LBPP时UA-XSA下降，UA-MWC显著增加。尽管LFV和IJVVol的变化相似，但两组之间响应LBPP时UA-XSA和UA-MWC的变化有显著差异（分别为p = 0.006和p < 0.001）。
我们的结果表明，头侧液体移位可能至少部分通过液体渗入UA黏膜导致UA变窄，从而促成OSA的发病机制。
