title: Duration of intraocular gases following vitreoretinal surgery.
abstract: BACKGROUND
  Intraocular gas tamponades are an important tool in modern vitreoretinal surgery. However, there is considerable variation in their use and perceptions amongst clinicians regarding these agents.
  
  
  METHODS
  An electronic survey of vitreoretinal surgeons in the UK was undertaken to establish the patterns of use and surgeons' estimates of the longevity and expansion timing of gas tamponades. In addition, data were prospectively collected on the longevity of gas tamponades in 114 patients from our unit. An analysis was performed to identify patient or surgery factors affecting gas longevity RESULTS: A wide variation in the patterns of use and estimates of longevity and expansion timing of intraocular tamponades was found in the survey of vitreoretinal surgeons. Data from our unit give informed estimates on the longevity of three commonly used tamponades. For 30 % sulphur hexafluoride (SF6), mean 18.0 days, standard deviation (SD) 2.6 days. For 20 % hexafluoroethane (C2F6), mean 34.5 days, SD 3.3 days. For 15 % perfluoropropane (C3F8), mean 67.7 days SD 5.5 days. In the C2F6 group there was correlation between longer duration of the gas bubble and longer axial length (r = 0.438, p = 0.02) and longer gas duration with male sex (p = 0.002).
  
  
  CONCLUSIONS
  We present informed gas tamponade longevity figures in clinical practice and report statistically significant associations between longer gas longevity and increasing axial length and male sex.
authors.affiliation: Department of Ophthalmology, St Thomas' Hospital, Westminster Bridge Road, London, SE1 7EH, UK. akontos@doctors.org.uk.
authors.forename: Andreas
authors.initials: A
authors.lastname: Kontos
authors.affiliation: Department of Ophthalmology, St Thomas' Hospital, Westminster Bridge Road, London, SE1 7EH, UK.
authors.forename: James
authors.initials: J
authors.lastname: Tee
authors.affiliation: Department of Ophthalmology, Queen Mary's Hospital, Frognal Avenue, Sidcup, DA14 6LT, UK.
authors.forename: Alastair
authors.initials: A
authors.lastname: Stuart
authors.affiliation: Department of Ophthalmology, Queen Mary's Hospital, Frognal Avenue, Sidcup, DA14 6LT, UK.
authors.forename: Zaid
authors.initials: Z
authors.lastname: Shalchi
authors.affiliation: Department of Ophthalmology, St Thomas' Hospital, Westminster Bridge Road, London, SE1 7EH, UK.
authors.forename: Tom H
authors.initials: TH
authors.lastname: Williamson
mesh_terms: D000328:Adult; D058450:Endotamponade / Q000379:methods*; D005260:Female; D005466:Fluorocarbons / Q000008:administration & dosage*; D005500:Follow-Up Studies; D006801:Humans; D008297:Male; D008875:Middle Aged; D011446:Prospective Studies; D012164:Retinal Diseases / Q000601:surgery*; D013459:Sulfur Hexafluoride / Q000008:administration & dosage*; D013997:Time Factors; D014821:Vitrectomy / Q000379:methods*; D014822:Vitreous Body / Q000601:surgery*
chemical_list: D005466:Fluorocarbons; C048381:perfluoroethane; D013459:Sulfur Hexafluoride
keywords: C2F6; C3F8; Duration; Intraocular gas; SF6; Tamponade; Vitrectomy