title: Retrograde air escape via the nasolacrimal system: a previously unrecognized complication of continuous positive airway pressure in the management of obstructive sleep apnea.
abstract: BACKGROUND
  Continuous positive airway pressure (CPAP) is the gold standard treatment for moderate to severe obstructive sleep apnoea (OSA). Eye-related side effects of CPAP are commonly attributed to a poorly sealed mask, allowing leaked air to blow over the eye.
  
  
  METHODS
  We present 3 cases where attended polysomnography (A-PSG) demonstrated CPAP-associated retrograde air escape via the nasolacrimal system (CRANS) in the absence of any mask leaks. Symptoms included dry eye, epiphora, air escape from the medial canthus, and eyelid flutter. Symptoms were controlled with a variety of surgical and nonsurgical techniques.
  
  
  CONCLUSIONS
  CRANS represents a previously undescribed clinical entity. CRANS may be responsible for some CPAP-related eye side effects and possibly for rarer secondary eye complications, including conjunctivitis and corneal ulceration. CRANS should be suspected in any patient on CPAP complaining of eye symptoms. CRANS may be diagnosed through careful observation during A-PSG and confirmed by performing a "saline bubble test." Management options include nonsurgical (mask alternatives, humidification, nasopharyngeal airway) and surgical techniques (nasal airway surgery, inferior turbinate out-fracture and adhesion, injection of bulking agent around Hasner's valve).
authors.affiliation: Department of Otolaryngology, Head and Neck Surgery, Westmead Hospital/University of Sydney, Sydney, Australia.
authors.forename: Narinder Pal
authors.initials: NP
authors.lastname: Singh
authors.forename: Robbie James Eades
authors.initials: RJ
authors.lastname: Walker
authors.forename: Fiona
authors.initials: F
authors.lastname: Cowan
authors.forename: Arthur Craig
authors.initials: AC
authors.lastname: Davidson
authors.forename: David Newton
authors.initials: DN
authors.lastname: Roberts
mesh_terms: D000328:Adult; D000388:Air; D045422:Continuous Positive Airway Pressure / Q000009:adverse effects*; D005128:Eye Diseases / Q000175:diagnosis / Q000209:etiology / Q000601:surgery; D006801:Humans; D008297:Male; D008875:Middle Aged; D009301:Nasolacrimal Duct / Q000033:anatomy & histology / Q000502:physiology*; D020181:Sleep Apnea, Obstructive / Q000628:therapy*
keywords: continuous positive airway pressure; eye; nasolacrimal duct; obstructive sleep apnea