Intraocular pressure and quality of blockade in peribulbar anesthesia using ropivacaine or lidocaine with adrenaline: a double-blind randomized study

Evaluation of efficacy of peribulbar block with the combination of 2% lidocaine and 0.5% bupivacaine in comparison with 2% lidocaine and 0.75% ropivacaine in cataract surgery

Introduction

Cataract surgery is performed under peribulbar or retrobulbar block. Majority of the patients posted for cataract have some form of medical diseases like diabetes, hypertension, angina, ischaemic heart disease etc. Lidocaine and bupivacaine are the most commonly used local anesthetic for the block procedure. Here we compare the efficacy of peribulbar block in cataract surgery using the combination of 1:1 mixture of 2% lidocaine with 0.5% bupivacaine and 1:1 mixture of 2% lidocaine with 0.75% ropivacaine.

Materials and Methods

It is a prospective, randomized, double blinded study including 60 patients were devided into two groups of 30 each, Group-R received 8 ml of 1:1 mixture of 4 ml of 2% lidocaine, 4 ml of 0.75% ropivacaine and 15 IU/ml of hyaluronidase and group-B received 8 ml of 1:1 mixture of 4 ml of 2% lidocaine, 4 ml of 0. 5% bubivacaineand 15 IU/ml of hyaluronidase. Peribulbar block was performed as per Bloomberg's modification of the Davis and Mandel technique where 5 ml of local anesthetic was injected in the infero temporal region and 3 ml of drug was injected in the superi nasal area. Patients were assessed for sensory block, eyelid and occular movements at an interval of 2 minutes. Systolic, diastolic and mean arterial pressures, heart rate, oxygen saturation, ECG were monitored non invasively at 1,3,5,8,10,15 and then every 10 minutes till the end of the surgery.

Observation and Discussion

Mean time for the onset of sensory blockade was 2.70 ± 6.5 minutes in Group B and 2.63 ± 0.57 minutes in group R with P-value 0.671, showing no significant difference in the onset of sensory blockade. Onset of motor blockade was 6.53 ± 1.81 minutes in group B, and 7.57 ± 1.46 minutes in the group R, the P-value being 0.018 was statistically significant. Regarding the duration of analgesia, our study showed mean time for analgesia lasted for 295 ± 54.63 minutes in group B and 414.67 ± 99.47 in group R with P value 0.001 showing statistically significant prolongation of duration of analgesia with group R. We observed a significant increase of mean IOP in bupivacaine group from 13.333 ± 1.582 mm Hg to 21.966 ± 2.697 mm Hg, whereas in ropivacaine group it increased from 12.766 ± 1.222 mm Hg to 13.0 ± 1.341 mm Hg after peribulbar anaesthesia.

PRESSÃO INTRAOCULAR, PRESSÃO ARTERIAL MÉDIA E DIÂMETRO PUPILAR EM COELHOS ( (Oryctolagus cuniculus) ) SUBMETIDOS AO BLOQUEIO RETROBULBAR COM DIFERENTES PROTOCOLOS ANESTÉSICOS

Resumo O objetivo deste estudo foi buscar novos protocolos de anestesia loco regional para procedimentos oftálmicos que proporcionem segurança e manutenção das funções vitais, além de manter a pressão intraocular estável, com centralização do bulbo do olho e acinesia palpebral. Foram utilizados 20 coelhos da raça Nova Zelândia para a realização de quatro protocolos de anestesia local através do bloqueio retrobulbar com lidocaína 2% com vasoconstritor, lidocaína 2% sem vasoconstritor associada ao tramadol, ropivacaína 1% e bupivacaína 0,5%, cada animal recebeu o volume anestésico de 1,0 mL. Todos os protocolos anestésicos utilizados promoveram acinesia palpebral e centralização do bulbo do olho durante todo o período de avaliação. A realização do bloqueio retrobulbar com os protocolos anestésicos demonstrou ser factível e segura quanto à manutenção da pressão intraocular, pressão arterial invasiva e diâmetro pupilar e pode ser utilizada para realização de cirurgias intraoculares. Os anestésicos proporcionaram bom bloqueio retrobulbar, entretanto a bupivacaína foi o anestésico que ocasionou o maior diâmetro pupilar comparativamente aos demais fármacos testados.

The quest for effective pain control during suture adjustment after strabismus surgery: a study evaluating supplementation of 2% lidocaine with 0.4% ropivacaine

Purpose

To determine whether the addition of 0.4% ropivacaine to the standard 2% lidocaine peribulbar anesthetic block improves pain scores during suture adjustment in patients undergoing strabismus surgery with adjustable sutures.

Methods

Prospective, double-blind study of 30 adult patients aged 21–84 years scheduled for elective strabismus surgery with adjustable sutures. Patients were divided into two groups of 15 patients each based on the local anesthetic. Group A received 2% lidocaine and Group B received 2% lidocaine/0.4% ropivacaine. Pain was assessed using the visual analog scale (VAS) preoperatively and at 2, 4, and 6 hours postoperatively. The Lancaster red-green test was used to measure ocular motility at the same time points.

Results

The pain scores in the two groups were low and similar at all measurement intervals. The VAS for Group A versus Group B at 2 hours (1.7 versus 2.4, P=0.5) and 4 hours (3.5 versus 3.7, P=0.8) showed no benefit from the addition of ropivacaine. At 6 hours, the VAS (3.7 versus 2.7) was not statistically significant, but the 95% confidence interval indicated that ropivacaine may provide some benefit. A repeated measures ANOVA did not find a statistically significant difference in VAS scores over time (P=0.9). In addition, the duration of akinesia was comparable in both groups (P=0.7).

Conclusion

We conclude that the 50:50 mixture of 2% lidocaine with 0.4% ropivacaine as compared to 2% lidocaine in peribulbar anesthetic blocks in adjustable-suture strabismus surgery does not produce significant improvements in pain control during the postoperative and adjustment phases. In addition, ropivacaine did not impair return of full ocular motility at 6 hours, which is advantageous in adjustable-suture strabismus surgery.

Update on the clinical utility and practical use of ropivacaine in Chinese patients

We reviewed the Chinese and English literature for efficacy and tolerability data as well as pharmacological properties of ropivacaine in Chinese patients. Ropivacaine is a long-acting amide local anesthetic agent that elicits nerve block via reversible inhibition of sodium ion influx in nerve fibers. The available evidence in the literature on anesthesia practice indicates that ropivacaine produces equally surgical sensory block and postoperative and obstetrics analgesia with good maternal and fetal outcome to those of bupivacaine or levobupivacaine. It appears to be associated with comparable onset, quality, and duration of sensory block, but with a lower incidence or grade of motor block, compared to bupivacaine. The satisfaction of both patients and surgeons is high when ropivacaine is used. Thus, ropivacaine appears to be an important option for regional anesthesia and for the management of postoperative and labor pain, with its enhanced sensorimotor differentiation blockage at lower concentrations and enhanced safety at higher concentrations.

Effects of intravitreal ropivacaine on retinal thickness and integrity in the guinea pig

BACKGROUND

Retrobulbar anesthesia is widely used for ocular surgery.Ocular complications are possible when retrobulbar anesthesia is accidentally injected intravitreally.

OBJECTIVE

The aim of this study was to determine the relative retinal toxicitiesof ropivacaine hydrochloride, a local anesthetic, using various concentrations in guinea pigs.

METHODS

This randomized, investigator-masked, experimental study wasconducted at the Department of Anesthesiology, Dicle University, Diyarbakir, Turkey. The right eyes of 18 guinea pigs were assigned to 1 of 3 treatment groups: 1%, 0.75%, or 0.5% ropivacaine. The right eye of each animal was injected intravitreally with 0.1 mL of 1%, 0.75%, or 0.5% ropivacaine. The left eye of each animal was injected with a balanced saline solution (control). The guinea pigs were euthanized 7 days after injection, and the retinal structures were examined using light microscopy. The total thickness of each retina was measured using an ocular micrometer.

RESULTS

No histologic abnormalities were observed in the control eyes.Retinal damage of most of the retinal section was seen in the eyes receiving study drug. The eyes injected with 0.5% ropivacaine had a generally intact appearance, with the exception of some atrophy and disorganization. Overall, the eyes injected with 1% ropivacaine had significantly more extensive retinal thinning compared with the eyes injected with 0.75% or 0.5% ropivacaine (both, P < 0.01). In the eyes injected with 0.75% or 1% ropivacaine, disorganization of the structure of the retinal layers and atrophy were noted on histopathology. The mean total thicknesses of the retina were significantly less in all ropivacaine-treated eyes compared with that in the controls (P < 0.001).

CONCLUSIONS

In this small experimental study, ropivacaine had concentration-dependent toxic effects on guinea pig retinas.

Ocular pain after intravitreal injection

PURPOSE

To evaluate the efficacy of different anesthetics and topical anti-inflammatory treatment in patients undergoing intravitreal injections (IVI).

METHODS

Prospective, randomized, double masked, comparative study. Patients undergoing 0.05 mL IVI were randomized to two different preoperative anesthetic regimes (regime A [0.5% tetracaine + naphazoline] versus regime B [5% lidocaine]) and two different post-injection topical protocols (protocol 1 [tobramycin qid] versus protocol 2 [tobramycin qid + diclofenac qid]). Patients were trained to score pain using a numerical rating pain scale from 0 (no pain) to 10 (excruciating pain) immediately after the injection, 30 min and 24 h later. Patients were instructed to take oral paracetamol (650-1000 mg, adjusted to the patient's weight) every six hours ad lib if necessary.

RESULTS

A total of 156 patients were enrolled; 86 patients were randomized to regime A and 70 to regime B; 78 patients were assigned to each of the post-injection topical protocols. The average pain score immediately after the IVI was 2.77 (SD 2.12) for the whole group (2.85, SD 2.23 with tetracaine and 2.67, SD 2.00 with lidocaine; p = 0.73, Mann-Whitney U-test). Twenty-four hours later, the average pain score was 1.84, SD 2.45 (topical diclofenac + tobramycin) versus 1.75, SD 1.83 (topical tobramycin; p = 0.46, Mann-Whitney U-test). Forty-seven patients (30%) required oral paracetamol (average 3.3 and range 1-5 tablets). Conjunctival hemorrhage 30 min after the injection was less frequent and severe in eyes treated with topical naphazoline (p = 0.055, Mann-Whitney U-test).

CONCLUSIONS

Topical tetracaine and lidocaine provide similar anesthesia before IVI. Topical diclofenac does not seem to reduce pain scores after IVI.

Anestesia peribulbar com ropivacaína como alternativa ao bloqueio neuromuscular para facectomia em cães

Desenvolveu-se uma técnica de bloqueio peribulbar comparando-a à técnica de anestesia oftálmica com bloqueio neuromuscular parcial em cães submetidos à facectomia extracapsular. Doze cães, de diferentes raças, foram alocados em dois grupos (G1 e G2) e anestesiados com acepromazina (0,05mg/kg, IV) e propofol (5mg/kg, IV) e mantidos com isofluorano sob ventilação espontânea. Os cães do G1 receberam o bloqueio peribulbar com ropivacaína 0,75%, e os do G2 o bloqueio neuromuscular parcial com brometo de pancurônio (0,01mg/kg, IV). Utilizaram-se, como parâmetros comparativos, escores de posicionamento do globo ocular, controle do reflexo oculocardíaco e pressão intraocular (mmHg). Foi possível propor uma técnica eficaz para cães baseando-se na técnica de bloqueio peribulbar posterior realizada no homem. Em ambos os grupos, o globo ocular permaneceu centralizado. Não ocorreram alterações eletrocardiográficas atribuídas ao reflexo oculocardíaco. Houve redução significativa da pressão intraocular em G1 após o bloqueio (10,7±0,6 e 14,7±0,6). Conclui-se que o bloqueio peribulbar proporcionou condições cirúrgicas apropriadas para a realização da facectomia, com a vantagem de promover bloqueio sensitivo do olho.

Ropivacaine: a review of its use in regional anaesthesia and acute pain management

Ropivacaine (Naropin) is the pure S(-)-enantiomer of propivacaine, and is a long-acting amide local anaesthetic agent, eliciting nerve block via reversible inhibition of sodium ion influx in nerve fibres. Ropivacaine is a well tolerated regional anaesthetic effective for surgical anaesthesia as well as the relief of postoperative and labour pain. The efficacy of ropivacaine is similar to that of bupivacaine and levobupivacaine for peripheral nerve blocks and, although it may be slightly less potent than bupivacaine when administered epidurally or intrathecally, equi-effective doses have been established. Clinically adequate doses of ropivacaine appear to be associated with a lower incidence or grade of motor block than bupivacaine. Thus ropivacaine, with its efficacy, lower propensity for motor block and reduced potential for CNS toxicity and cardiotoxicity, appears to be an important option for regional anaesthesia and for the management of postoperative and labour pain.

Liquid Chromatographic Determination of Plasma Ropivacaine for Assessing Pharmacokinetics of the Viscous Preparation

We developed assay method for determination of plasma ropivacaine by using reversed-phase high performance liquid chromatography (HPLC) equipped with ordinary octadecylsilyl silica-gel (ODS) column. Plasma samples spiked with internal standard (bupivacaine) were treated by ethylacetate to extract ropivacaine and internal standard. The ropivacaine and internal standard separated on ODS column were detected by an ultra violet (UV) detector set at 215 nm. The mobile phase solvent consisted of acetonitrile, methanol and 0.05 M phosphate buffer adjusted to pH 4.0 (10 : 30 : 60, v/v) was pumped at a flow rate of 0.8 ml/min. The calibration curve of ropivacaine was linear at the concentration of 25-1,000 ng/ml (r=0.9998). The recoveries of ropivacaine from plasma were greater than 87.9% with the coefficient of variations (CVs) less than 6.1%. The CVs for intra- and inter-day assay of ropivacaine were 2.0-12.0% and 1.7-14.8%, respectively. This HPLC method was applied to determining plasma ropivacaine in two healthy subjects after receiving 0.5% ropivacaine viscous preparation, which was prepared in our hospital. Our preliminary pharmacokinetic data showed that ropivacaine viscous could be used safely based on the plasma ropivacaine concentrations (C(max): 89-125 ng/ml) for pain relief in oral mucosa.