title: CPAP washout prior to reevaluation polysomnography: a sleep surgeon's perspective.
abstract: OBJECTIVE
  Obstructive sleep apnea (OSA) is characterized by repetitive upper airway collapse during sleep, leading to decreased oxygen blood levels and arousal from sleep. The gold standard treatment option for moderate to severe OSA is considered continuous positive airway pressure (CPAP). In case primary treatment with CPAP fails, a reevaluation of disease severity [by means of the apnea/hypopnea-index (AHI)] can be required. A subset of patients that prefer a CPAP alternative is still using CPAP until the reevaluation polysomnography (PSG), and a so-called washout effect is not ruled out. The purpose of this study is to evaluate the evidence on the existence and duration of this washout effect and its clinical relevance for current practice.
  
  
  METHODS
  To identify papers for this review, an extensive literature search was run electronically through MEDLINE and EMBASE databases.
  
  
  RESULTS
  An overview of currently available literature on this washout effect and the findings of 13 studies on this topic are discussed.
  
  
  CONCLUSIONS
  There is some evidence that CPAP washout exists in patients with a stable BMI throughout the follow-up period. However, the intensity and duration of this effect remains unclear. Within the limitations of the present study, it seems reasonable to maintain a washout period of 1 week, in case alternative treatments options are considered and especially when a baseline PSG (and subsequent repeat PSG after treatment) is needed in case of clinical trials.
authors.affiliation: Department of ENT, Head and Neck Surgery, Saint Lucas Andreas Hospital, Jan Tooropstraat 164, 1061 AE, Amsterdam, The Netherlands, anneclaire.vroegop@uza.be.
authors.forename: Anneclaire V M T
authors.initials: AV
authors.lastname: Vroegop
authors.forename: Jim W
authors.initials: JW
authors.lastname: Smithuis
authors.forename: Linda B L
authors.initials: LB
authors.lastname: Benoist
authors.forename: Olivier M
authors.initials: OM
authors.lastname: Vanderveken
authors.forename: Nico
authors.initials: N
authors.lastname: de Vries
mesh_terms: D015992:Body Mass Index; D002986:Clinical Trials as Topic; D003131:Combined Modality Therapy; D045422:Continuous Positive Airway Pressure; D003299:Cooperative Behavior; D006801:Humans; D033183:Interdisciplinary Communication; D013517:Otorhinolaryngologic Surgical Procedures; D017286:Polysomnography; D020181:Sleep Apnea, Obstructive / Q000175:diagnosis / Q000628:therapy*