Intraocular pressure and ropivacaine in peribulbar block: A comparative study with bupivacaine

Abstract

Ropivacaine 1.0% associated with hyaluronidase in peribulbar block is better than 0.75% bupivacaine under the same standard conditions for lowering IOP in intraocular surgery. This effect is probably due to relaxation of the extraocular muscles after the block with both anesthetics, and possibly to a smaller intraocular blood volume due to vasoconstriction in the case of ropivacaine.

Anestesia peribulbar com ropivacaína: estudo da ação vasoconstritora

“…A small increase, between 13 mmHg and 15.6 mmHg was observed without clinical significance, since the levels remained within normal limits. This increase, followed by a reduction of the intraocular pressure in bupivacaine group, is in agreement with other reports in the literature 15,50 . In ropivacaine group, a significant reduction or even a tendency towards stabilization of intraocular pressure was observed with values around 13 mmHg in all measurements.…”

“…Those results also confirm the findings of other authors who have reported the absence of an increase in this parameter after peribulbar anesthesia with ropivacaine 51 . The difference between both groups observed in the present study, as well as suggested by Nociti et al 50 , could be due to the intrinsic vasoconstrictive property of ropivacaine.…”

“…Nevertheless, Huha et al 35 demonstrated that the lower liposolubility of ropivacaine favors plasma levels relatively higher than bupivacaine. The lower levels of intraocular pressure were attributed to the vasoconstrictor effects of ropivacaine, when compared to bupivacaine, in the study by Nociti et al 50 However, the authors did not evaluate other parameters that could have proven this hypothesis. The present study is, possibly, the first to analyze the action of ropivacaine on the ocular blood flow and to demonstrate the effects of its vasoconstrictive property through the peribulbar approach, demonstrating that it is capable of reducing the ocular pulse amplitude in a higher magnitude than bupivacaine.…”

“…A study with 40 patients described that, despite similar blockade with analgesia and akinesia, 1% ropivacaine decreased the intraocular pressure immediately after its administration, unlike 0.75% bupivacaine, which promoted an initial elevation in intraocular pressure followed by a reduction. The authors suggested that the difference could be due to the vasoconstrictive action of ropivacaine 50 . However, one should take into consideration that comparing different concentrations of local anesthetics could affect the intensity of the motor blockade resulting in inaccurate evaluations of intraocular pressure.…”

“…Peribulbar anesthesia can cause a temporary increase in the intraocular pressure due to the compressive effect of anesthetic solution on the eye and increase in intraorbital pressure. However, after the onset of akinesia -due to relaxation of extrinsic ocular musculature -a reduction in intraocular pressure is observed 50 . In the current study, the interference of the extraocular musculature on intraocular pressure was considered similar in both groups since all patients presented complete akinesia at 5 and 10 minutes after the blockade.…”