title: The effect of pars plan vitrectomy on oxygen saturation in retinal vessels--a pilot study.
abstract: OBJECTIVE
  To determine the effect of pars plana vitrectomy (PPV) on oxygen saturation in retinal vessels.
  
  
  METHODS
  We performed a prospective consecutive interventional case series of 20 eyes of 20 patients with macular hole or epiretinal membrane. We performed automatic retinal oximetry (Oxymap Inc., Reykjavik, Iceland) in each patient 24 hr prior to and 45 days (range 42-49) after PPV (classic 20G or sutureless 23G). We analysed oxygen saturations in retinal arteries and veins. Vessel segments of first or second degree were selected. The same segment was analysed before and after PPV. Oximetry data were compared by paired two-tailed t-test.
  
  
  RESULTS
  Pars plana vitrectomy did not alter arterial haemoglobin saturation with oxygen (98±2% prior to the surgery and 98±3% after the procedure, p=0.549). The mean venous haemoglobin saturation with oxygen increased after vitrectomy from 63±10% to 66±8% (p=0.012).
  
  
  CONCLUSIONS
  Oxygen saturation is higher in retinal veins after pars plana vitrectomy. Further studies are needed to unveil the mechanism of how vitrectomy affects oxygen metabolism in the retina.
authors.affiliation: Department of Ophthalmology, Faculty of Medicine and Dentistry, University Hospital, Palacky University Olomouc, Olomouc, Czech RepublicDepartment of Medical Biophysics, Faculty of Medicine and Dentistry, Institute of Molecular and Translational Medicine, Palacky University, Olomouc, Czech Republic.
authors.forename: Martin
authors.initials: M
authors.lastname: Sín
authors.forename: Irena
authors.initials: I
authors.lastname: Sínová
authors.forename: Oldřich
authors.initials: O
authors.lastname: Chrapek
authors.forename: Zuzana
authors.initials: Z
authors.lastname: Prachařová
authors.forename: Marta
authors.initials: M
authors.lastname: Karhanová
authors.forename: Kateřina
authors.initials: K
authors.lastname: Langová
authors.forename: Jiři
authors.initials: J
authors.lastname: Rehák
mesh_terms: D000368:Aged; D000369:Aged, 80 and over; D001794:Blood Pressure / Q000502:physiology; D019773:Epiretinal Membrane / Q000503:physiopathology / Q000601:surgery*; D005260:Female; D006801:Humans; D007429:Intraocular Pressure / Q000502:physiology; D008297:Male; D008875:Middle Aged; D010092:Oximetry; D010100:Oxygen / Q000097:blood*; D010865:Pilot Projects; D011446:Prospective Studies; D012167:Retinal Perforations / Q000503:physiopathology / Q000601:surgery*; D012171:Retinal Vessels / Q000502:physiology*; D014821:Vitrectomy
chemical_list: D010100:Oxygen
keywords: oxygen saturation; pars plana vitrectomy; retinal blood flow velocity; retinal vessel blood saturation