title: Relationship of pharyngeal water content and jugular volume with severity of obstructive sleep apnea in renal failure.
abstract: BACKGROUND
  In patients with end-stage renal disease (ESRD), fluid overload may contribute to their high prevalence of obstructive sleep apnea (OSA) by increasing the amount of fluid displaced from the legs into the neck overnight, and possibly compressing the upper airway (UA). Indeed, in ESRD patients, the amount of overnight rostral fluid displacement from the legs is related to the frequency of apneas and hypopneas per hour of sleep (apnea-hypopnea index, AHI). We, therefore, hypothesized that in ESRD patients, the greater the UA-mucosal water content (UA-MWC) and internal jugular vein volume (IJVVol), the higher the AHI.
  
  
  METHODS
  We studied 20 patients with ESRD on thrice weekly hemodialysis who had undergone diagnostic polysomnography (age 41.0 ± 12.3 years, with a body mass index (BMI) of 25.8 ± 6.3 kg/m(2) and an AHI of 20.2 ± 26.8). The leg fluid volume (LFV) was measured by bioelectric impedance. The IJVVol and MWC were measured by UA magnetic resonance imaging (MRI).
  
  
  RESULTS
  The only significant independent correlates of the AHI were IJVVol (r = 0.801, P < 0.0001) and UA-MWC (r = 0.720, P = 0.0005) which together explained 72% of its variability.
  
  
  CONCLUSIONS
  These data suggest that fluid overload via increased IJVVol, and UA-MWC, contributes to the pathogenesis of OSA in patients with ESRD. These findings help us to explain the high prevalence of OSA in ESRD patients, and attenuation of OSA in association with nocturnal dialysis. They also suggest the need for randomized trials to determine whether more aggressive fluid removal in ESRD patients will alleviate OSA.
authors.affiliation: Sleep Research Laboratory of the Toronto Rehabilitation Institute, Toronto, Ontario, Canada.
authors.forename: Rosilene M
authors.initials: RM
authors.lastname: Elias
authors.forename: Christopher T
authors.initials: CT
authors.lastname: Chan
authors.forename: Narinder
authors.initials: N
authors.lastname: Paul
authors.forename: Shveta S
authors.initials: SS
authors.lastname: Motwani
authors.forename: Takatoshi
authors.initials: T
authors.lastname: Kasai
authors.forename: Joseph M
authors.initials: JM
authors.lastname: Gabriel
authors.forename: Neil
authors.initials: N
authors.lastname: Spiller
authors.forename: Thomas D
authors.initials: TD
authors.lastname: Bradley
mesh_terms: D000328:Adult; D000403:Airway Resistance; D001826:Body Fluids / Q000502:physiology*; D017097:Electric Impedance; D005260:Female; D018495:Fluid Shifts; D005500:Follow-Up Studies; D006801:Humans; D007676:Kidney Failure, Chronic / Q000150:complications*; D008279:Magnetic Resonance Imaging; D008297:Male; D010614:Pharynx / Q000503:physiopathology*; D017286:Polysomnography; D011379:Prognosis; D006435:Renal Dialysis / Q000009:adverse effects*; D020181:Sleep Apnea, Obstructive / Q000209:etiology*; D014867:Water / Q000737:chemistry*
chemical_list: D014867:Water