title: Impairment of ocular blood flow during regional orbital anesthesia.
abstract: BACKGROUND
  Regional anesthesia for ophthalmic surgery has been associated with ischemic complications, such as central retinal vascular occlusion, optic atrophy and ischemic optic neuropathy. Impairment of pulsatile ocular blood flow (POBF) may occur with regional orbital anesthesia. In this study we quantified POBF in patients undergoing regional orbital anesthesia.
  
  
  METHODS
  Eleven patients (12 eyes) with a mean age of 76.5 years having regional orbital anesthesia for cataract or retinal surgery at a private refractive surgical centre in Calgary had POBF monitoring before, during and 15 minutes after induction of anesthesia.
  
  
  RESULTS
  There were no significant changes in intraocular pressure or heart rate during the induction phase or 15 minutes after induction of regional orbital anesthesia. However, ocular blood flow indices, including pulse amplitude, pulse volume and POBF, were significantly reduced following attainment of regional orbital blockade (p < 0.05). With time there was recovery in these variables, but they all remained significantly reduced from baseline 15 minutes later.
  
  
  CONCLUSIONS
  Ocular blood flow appears to be significantly impaired during regional orbital anesthesia, induced as described. There could be benefit in monitoring POBF to reveal otherwise undetectable deleterious effects on retinal circulation in patients having retrobulbar injections, orbital compression or digital manipulation of the globe.
authors.affiliation: University of Ottawa Eye Institute, Ottawa Hospital, General Campus, 501 Smyth Rd., Ottawa ON K1H 8L6. scoupland@ottawahospital.on.ca
authors.forename: S G
authors.initials: SG
authors.lastname: Coupland
authors.forename: M C
authors.initials: MC
authors.lastname: Deschênes
authors.forename: R C
authors.initials: RC
authors.lastname: Hamilton
mesh_terms: D000368:Aged; D000772:Anesthesia, Local; D000779:Anesthetics, Local / Q000008:administration & dosage; D001783:Blood Flow Velocity; D002387:Cataract Extraction; D002829:Choroid / Q000098:blood supply*; D005260:Female; D006339:Heart Rate; D006801:Humans; D007429:Intraocular Pressure; D008297:Male; D009915:Orbit; D011673:Pulsatile Flow; D012039:Regional Blood Flow; D012164:Retinal Diseases / Q000601:surgery; D014065:Tonometry, Ocular
chemical_list: D000779:Anesthetics, Local