Influence of infusion volume on the ocular hemodynamic effects of peribulbar anesthesia.
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.
Lung
Solveig
S
Department of Clinical Pharmacology, Medical University of Vienna, Vienna, Austria.
Luksch
Alexandra
A
Weigert
Günther
G
Georgopoulos
Michael
M
Menapace
Rupert
R
Polska
Elzbieta
E
Garhofer
Gerhard
G
Findl
Oliver
O
Schmetterer
Leopold
L
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*
D019162:Anesthetics, Combined; D000779:Anesthetics, Local; D008012:Lidocaine; D006821:Hyaluronoglucosaminidase; D002045:Bupivacaine