Intraocular pressure and pulsatile ocular blood flow after retrobulbar and peribulbar anaesthesia

Abstract

Aims-This study investigated the eVect of peribulbar and retrobulbar local anaesthesia on intraocular pressure (IOP) and pulsatile ocular blood flow (POBF), as such anaesthetic techniques may adversely aVect these parameters. Methods-20 eyes of 20 patients who were to undergo phacoemulsification cataract surgery were prospectively randomised to receive peribulbar or retrobulbar anaesthesia. The OBF tonometer (OBF Labs, Wiltshire, UK) was used to simultaneously measure IOP and POBF before anaesthesia and 1 minute and 10 minutes after anaesthesia. Between group comparisons of age, baseline IOP, and baseline POBF were performed using the non-parametric Mann-Whitney test. Within group comparisons of IOP and POBF measured preanaesthesia and post-anaesthesia were performed using the non-parametric Wilcoxon signed ranks test for both groups. Results-There was no statistically significant IOP increase post-anaesthesia in either group. In the group receiving peribulbar anaesthesia, there was a significant reduction in POBF initially postanaesthesia which recovered after 10 minutes. In the group receiving retrobulbar anaesthesia, there was a persistent statistically significant reduction in POBF. Conclusions-Retrobulbar and peribulbar injections have little eVect on IOP. Ocular compression is not needed for IOP reduction when using local anaesthesia for cataract surgery. Conversely, POBF falls, at least for a short time, when anaesthesia for ophthalmic surgery is administered via a retrobulbar route or a peribulbar route. This reduction may be mediated by pharmacologically altered orbital vascular tone. It may be safer to use other anaesthetic techniques in patients with ocular vascular compromise. (Br J Ophthalmol 2001;85:796-798)

Influência da anestesia geral e bloqueio peribulbar em trabeculectomias: comparação visual e pressórica

“…(5-10) Em um estudo com bloqueio peribulbar, a PIO mostrou-se elevada e diminuiu o fluxo sanguíneo ocular pulsátil nos minutos iniciais, porém mostrou recuperação total após 10min (11) . Em outro estudo os pesquisadores concluíram que o aumento da PIO após bloqueio peribulbar pode ser lesivo em olhos glaucomatosos.…”

“…Em ambos os grupos os resultados da mediana da PIO esteve dentro do classificado como sucesso cirúrgico (PIO<21mmHg com ou sem medicação antiglaucomatosa) como demonstrado em outros estudos. (11,12,13) Em resumo, não encontramos diferenças significativas entres os resultados de TRECs realizadas com anestesia geral e bloqueio peribulbar, porém o número de pacientes analisados é pequeno, é necessário mais estudos com um número maior de pacientes para comprovar os efeitos mostrados.…”

Anestesia peribulbar com ropivacaína: estudo da ação vasoconstritora

“…Chang et al 2 compared the technique of peribulbar anesthesia with subconjunctival block; the reduction of pulsatile ocular flow in the first group was attributed to the pharmacological effects of the anesthetic solution. Retrobulbar block, which uses a smaller volume of local anesthetic, caused temporary elevation of the intraocular pressure and persistent reduction of the ocular pulsatile flow similar to the peribulbar technique in a study in 20 eyes 13 . 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 .…”

“…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 .…”

“…Several authors have suggested that peribulbar anesthesia promotes a reduction in pulsatile ocular blood flow by pharmacologically-mediated changes in the vascular caliber, compression of the vasculature by the volume of anesthetic administered in the orbit, or by elevation of the intraocular pressure associated with a reduction in perfusion pressure 12,13 .…”