title: Influence of infusion volume on the ocular hemodynamic effects of peribulbar anesthesia.
abstract: OBJECTIVE
  To test the hypothesis that ocular blood-flow response to peribulbar anesthesia can be reduced by using a smaller volume of anesthetic mixture.
  
  
  METHODS
  Departments of Ophthalmology and Clinical Pharmacology, Medical University of Vienna, Vienna, Austria.
  
  
  METHODS
  Twenty patients scheduled for bilateral age-related cataract surgery were enrolled in a prospective randomized balanced observer-masked crossover study. Two study days with a 2 mL injection volume or 5 mL injection volume used for peribulbar anesthesia were scheduled. On 1 study day, patients received the 1-dose regimen and on the other study day, when the contralateral eye had surgery, patients received the other injection volume. On both study days, the anesthetic mixture consisted of an equal amount of lidocaine, bupivacaine, and hyaluronidase independently of the injection volume. Intraocular pressure (IOP), blood pressure, and pulse rate were measured noninvasively. Ocular fundus pulsation amplitude (FPA) and peak systolic and end diastolic flow velocities in the central retinal artery were measured with laser interferometry and color Doppler imaging, respectively. The results were recorded as means +/- SD.
  
  
  RESULTS
  Peribulbar anesthesia increased IOP and reduced FPA and flow velocities in the central retinal artery. The effects on IOP (5 mL, 35.1% +/- 16.0%; 2 mL, 14.1% +/- 14.1%; P<.001) and ocular hemodynamic parameters (FPA: 5 mL, -17.5% +/- 7.8%/2 mL, -7.3% +/- 7.2%, P<.001; peak systolic velocity: 5 mL, -19.5% +/- 10.7%/2 mL, -10.6% +/- 9.8%, P = .013; end diastolic velocity: 5 mL, -16.7% +/- 6.2%/2 mL, -8.4% +/- 7.3%, P = .005) were more pronounced with the 5 mL injection volume than with the 2 mL injection volume.
  
  
  CONCLUSIONS
  An injection volume of 2 mL instead of 5 mL reduced the ocular blood-flow response to peribulbar anesthesia. This procedure may be used in patients with ocular vascular disease to reduce the incidence of anesthesia-induced ischemia and loss of vision.
authors.affiliation: Department of Clinical Pharmacology, Medical University of Vienna, Vienna, Austria.
authors.forename: Solveig
authors.initials: S
authors.lastname: Lung
authors.forename: Alexandra
authors.initials: A
authors.lastname: Luksch
authors.forename: Günther
authors.initials: G
authors.lastname: Weigert
authors.forename: Michael
authors.initials: M
authors.lastname: Georgopoulos
authors.forename: Rupert
authors.initials: R
authors.lastname: Menapace
authors.forename: Elzbieta
authors.initials: E
authors.lastname: Polska
authors.forename: Gerhard
authors.initials: G
authors.lastname: Garhofer
authors.forename: Oliver
authors.initials: O
authors.lastname: Findl
authors.forename: Leopold
authors.initials: L
authors.lastname: Schmetterer
mesh_terms: D000368:Aged; D000772:Anesthesia, Local / Q000379:methods; D019162:Anesthetics, Combined / Q000008:administration & dosage*; D000779:Anesthetics, Local / Q000008:administration & dosage*; D001783:Blood Flow Velocity / Q000187:drug effects; D001794:Blood Pressure / Q000187:drug effects; D002045:Bupivacaine / Q000008:administration & dosage*; D018592:Cross-Over Studies; D006339:Heart Rate / Q000187:drug effects; D006439:Hemodynamics / Q000187:drug effects; D006801:Humans; D006821:Hyaluronoglucosaminidase / Q000008:administration & dosage*; D007267:Injections; D007429:Intraocular Pressure / Q000187:drug effects; D017078:Laser-Doppler Flowmetry; D008012:Lidocaine / Q000008:administration & dosage*; D009915:Orbit; D018918:Phacoemulsification; D011446:Prospective Studies; D012161:Retinal Artery / Q000502:physiology*
chemical_list: D019162:Anesthetics, Combined; D000779:Anesthetics, Local; D008012:Lidocaine; D006821:Hyaluronoglucosaminidase; D002045:Bupivacaine