Influence of infusion volume on the ocular hemodynamic effects of peribulbar anesthesia

Abstract

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.

Anestesia peribulbar com ropivacaína: estudo da ação vasoconstritora

“…The authors of the study that compared peribulbar to parabulbar anesthesia in 40 patients did not observe changes in intraocular pressure due to the small volume of anesthetics administered and attributed to 2% lidocaine the responsibility for the reduction in ocular pulse amplitude 3 . Lung et al 28 compared two volumes of anesthetic solution in peribulbar anesthesia and the group that used the smaller volume showed less reduction in the parameter of ocular hemodynamics, corroborating the theory of pharmacological action. The results of those studies are not comparable to the present study, since they used different anesthetics and volumes, but it is apparent that peribulbar anesthesia is related to the reduction in pulsatile ocular blood flow due to the effects of the local anesthetics.…”

“…Important studies on the action of regional blocks on pulsatile blood flow performed measurements only until 5 minutes after the blockade 12,28,37 . Other similar studies also performed evaluations only until 10 minutes 2,3,13 .…”

“…Thus, the perfusion pressure can be represented by the difference between the mean arterial pressure and the intraocular pressure. In other words, the greater the intraocular pressure, the lower the ocular perfusion pressure and, consequently, smaller ocular blood flow 16,28,44 .…”

“…However, are controversies on its presence in the choroid 4,28,59 . Studies have reported the presence of auto-regulatory mechanisms in the choroid, possibly neurogenic or passive 46,59 .…”

“…Patients with diabetes, glaucoma, known bleeding disorders, on anti-hypertensive or anti-glaucoma medications, with a history of intolerance or allergy to any of the drugs involved in the study, were excluded. The size of the study population was chosen based on data available in the current literature 2,3, 12,13,28,37 .…”