Ropivacaine in peribulbar anesthesia - vasoconstrictive properties

Area of Science:

• Ophthalmology
• Anesthesiology
• Ocular Physiology

Background:

• Peribulbar anesthesia can impact ocular blood flow (OBF) through increased intraocular pressure (IOP) or drug effects.
• Ropivacaine, known for low toxicity and potential vasoconstriction, has not been extensively studied on ocular vasculature.
• Ocular pulse amplitude (OPA) serves as an indirect measure of OBF.

Purpose of the Study:

• To investigate the vasoconstrictive properties of ropivacaine in peribulbar anesthesia.
• To evaluate the effect of ropivacaine on ocular blood flow (OBF) using ocular pulse amplitude (OPA) measurements.

Main Methods:

• A randomized study involving 40 eyes undergoing peribulbar anesthesia.
• Two groups received either ropivacaine (n=20) or bupivacaine (n=20) anesthetic solution (7 mL, no vasoconstrictor).
• Evaluated IOP, ocular perfusion pressure (OPP), OPA, hemodynamics, and akinesia pre- and post-blockade using dynamic contour tonometry.

Main Results:

• No significant differences in hemodynamics or motor blockade intensity were observed between groups.
• Ropivacaine induced a greater reduction in OPA (-55.59% at 5 min, -59.67% at 10 min) compared to bupivacaine (-34.71% at 5 min, -28.82% at 10 min).
• Ropivacaine showed minimal changes in IOP (-0.88% at 5 min, -4.54% at 10 min) and OPP (1.5% at 5 min, 4.2% at 10 min), contrasting with bupivacaine's effects.

Conclusions:

• Ropivacaine significantly reduced ocular pulse amplitude, indicating a substantial decrease in ocular blood flow.
• The observed reduction in OBF with ropivacaine is likely due to its intrinsic vasoconstrictive properties.
• Ropivacaine presents a vasoconstrictive effect on ocular vasculature during peribulbar anesthesia.