title: Effect of nasal continuous positive airway pressure on edema in patients with obstructive sleep apnea.
abstract: OBJECTIVE
  Previous research has identified an association between idiopathic edema and obstructive sleep apnea (OSA) in women, but a causal relationship between OSA and edema has not been established. This study was undertaken to determine whether nasal continuous positive airway pressure (CPAP) lessens edema in patients with idiopathic edema and OSA.
  
  
  METHODS
  This was a case-series study that enrolled eight ambulatory, obese, adults with bilateral, pitting pre-tibial edema and OSA from an inner city family practice and a suburban family practice from July 1995 until March 2003. Enrollees underwent subjective and physical examination assessment of changes in edema after initiation of nasal CPAP.
  
  
  RESULTS
  All but one of the subjects had severe OSA. The edema was typically 1+ to 2+, and the duration of the edema ranged from 6 months to more than 20 years. Seven of the eight subjects experienced a reduction in the amount of edema following nasal CPAP (P=0.04).
  
  
  CONCLUSIONS
  In subjects with OSA and idiopathic edema, nasal CPAP reduces the amount of edema. If valid, these results indicate that OSA can cause edema.
authors.affiliation: Department of Family Medicine, Case Western Reserve University School of Medicine, Cleveland, OH, USA. blankfield@adelphia.net
authors.forename: Robert P
authors.initials: RP
authors.lastname: Blankfield
authors.forename: Mansoor
authors.initials: M
authors.lastname: Ahmed
authors.forename: Stephen J
authors.initials: SJ
authors.lastname: Zyzanski
mesh_terms: D016022:Case-Control Studies; D045422:Continuous Positive Airway Pressure / Q000379:methods*; D004489:Edema, Cardiac / Q000150:complications*; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D017286:Polysomnography; D012720:Severity of Illness Index; D020181:Sleep Apnea, Obstructive / Q000150:complications* / Q000175:diagnosis / Q000628:therapy*; D013977:Tibia