Safety and efficacy of various concentrations of topical lidocaine gel for intravitreal injection

EFFECT OF ANESTHESIA DURATION ON INTRAVITREAL INJECTION PAIN: A double-blinded, randomized, comparative study

PURPOSE

To determine the effect of different durations of topical anesthesia on intravitreal injection (IVI) pain.

METHODS

This was a double-blinded, randomized, comparative study . Three hundred and twelve sequential eyes undergoing IVI were randomized to one of six groups according to the duration of topical anesthesia (from 1 to 30 minutes, one group for every 5-minute range, Groups 1-6). Topical anesthesia before IVI was standardized. Patients graded their pain using the visual analog scale and the Wong-Baker FACES scale at 15 minutes after the procedure.

RESULTS

The pain scores among the six groups were significantly different for the visual analog scale ( P = 0.013) and Wong-Baker FACES scale ( P = 0.024). The mean pain scores for Group 4 were 1.97 ± 1.04 (visual analog scale) and 2.02 ± 1.08 (Wong-Baker FACES scale) and were significantly lower than those of Group 1, 2, 5, or 6.

CONCLUSION

The duration of topical anesthesia significantly correlated with IVI pain. Preoperative 0.5% proparacaine hydrochloride drops were most effective in relieving IVI pain 11 to 20 minutes after topical administration.

Cooling Anesthesia for Intravitreal Injections - A Review

Intravitreal (IVT) injections are the most common procedure performed in retinal clinics today. It has revolutionized the treatment of neovascular age-related macular degeneration (nAMD), diabetic macular edema, macular edema due to veinous occlusive disease and other forms of exudative maculopathy. Though IVT injections prevent vision loss, the discomfort at the time of the injection has been troublesome to patients. This has led to patients missing their regular and routine dosage of treatment. Various modes of pre-injection anesthetic methods have been tried but in vain. Lidocaine-based topical anesthesia, in the form of pledgets, topical gel or subconjunctival lidocaine injection, has been the standard of care (SOC) for IVT injections worldwide. This article highlights the role of cooling anesthesia in reducing pain, anxiety and discomfort associated with needle penetration at the time of injection. PubMed and MedLine search were related to anesthesia for intravitreal injections, cooling anesthesia, mechanism of cooling anesthesia, COOL-1 trial, COOL-2 trial, results of COOL-1 trial and ultrarapid cooling anesthesia.

Efficacy and Safety of Oxybuprocaine Hydrochloride Gel in Alleviating Pain during Male Urethral Catheterization: A Single-Center Randomized Controlled Study

BACKGROUND

The purpose of this study was to determine whether oxybuprocaine hydrochloride gel could alleviate pain during male catheterization.

METHODS

Between September 2021 and March 2022, a randomized controlled trial was conducted at the Urology Department of Harbin Medical University Cancer Hospital (China). A total of 192 adult male patients requiring catheterization were enrolled and randomly assigned to one of two groups: 96 in the test group and 96 in the control group. The test group included patients who received oxybuprocaine hydrochloride gel as urethral lubricant, while patients in the control group received liquid paraffin. The preoperative and postoperative pain scores were compared using nonparametric tests.

RESULTS

At the baseline, there was no significant difference between the two groups. There was no significant difference in preoperative pain scores between the test group (mean ± SD = 20.04 ± 2.68 mm) and the control group (mean ± SD = 20.21 ± 3.23 mm) (p=0.694). Postoperative pain scores increased significantly in the test (mean ± SD = 31.98 ± 2.57 mm, p < 0.001) and control groups (mean ± SD = 38.96 ± 2.02 mm, p < 0.001) groups. Postoperative pain scores were significantly lower in the test group (mean ± SD = 31.98 ± 2.57 mm) than those in the control group (mean ± SD = 38.96 ± 2.02 mm (p < 0.001).

CONCLUSIONS

The use of oxybuprocaine hydrochloride gel significantly reduced pain during male urethral catheterization. The study provides evidence for clinicians to use oxybuprocaine hydrochloride gel during male catheterization.

Cooling Anesthesia for Intravitreal Injection: Results of the Prospective Open-Label, Dose-Ranging COOL-1 Trial

Purpose

To evaluate the safety and efficacy of a novel medical device to provide cooling anesthesia to the eye as local anesthesia for intravitreal injections.

Study Design

First in human, open-label study of 43 subjects assessed at three different doses: −10°C for 20 seconds (group 1), −15°C for 15 seconds (group 2), and −15°C for 20 seconds (group 3). Main outcome measures were safety and pain of injection using a numeric rating scale (NRS).

Results

Cooling anesthesia did not result in any serious ocular adverse events. One grade 1 adverse event was a vasovagal response during cooling administration which resolved immediately after cooling. Mean NRS scores at the time of injection for each group ranged from 2.5 to 4.3 There was a statistically significant difference between pain scores of the 3 groups at injection in aggregate but not in pairwise comparisons (P value = 0.047). There was a statistically significant decrease in pain from injection to 5 minutes post injection in all groups (P value = 0.00008, 0.003, 0.0005 for groups 1, 2, 3, respectively) as well as from 5 minutes to 24–48 hours (P value = 0.00001, 0.018, and 0.0545 for groups 1, 2, 3, respectively).

Conclusion

The rapid cooling anesthesia device was well tolerated for achieving local anesthesia among patients receiving intravitreal injections with no serious ocular adverse events.

The prominence of the dosage form design to treat ocular diseases

The eye is susceptible to various diseases commonly difficult to treat. To overcome the barriers imposed by this organ for required drugs penetration, technological strategies have been implemented to ocular formulations. Among them are the use of temperature or electric stimuli and the development of nanoparticles. The objective of this review is to present the main barriers to ocular drug delivery and to discuss strategies used in the development of ocular dosage forms, primarily for topical delivery, to increase the local bioavailability of drugs, target their delivery and increase patient compliance. Results obtained in the last years related to the topical administration of liposomes, dendrimers, iontophoresis, among other nanoparticulate systems focused on ophthalmic delivery, will be addressed. Finally, some clinical trials and marketed formulations that use nanotechnology to topically treat eye diseases will be presented.

Systematic review: non-adherence and non-persistence in intravitreal treatment

Purpose

Intravitreal injection of VEGF inhibitors has become the standard of care for different macular diseases within the last years resulting in improved visual outcomes. Under real-life conditions, however, the necessity for frequent retreatments and reexaminations poses a burden for patients and treatment centers. Non-adherence and non-persistence to intravitreal treatment may lead to inferior clinical outcomes, and knowledge of contributing factors is crucial to improve adherence. This systematic review analyzes current literature for potential factors involved in non-adherence and non-persistence.

Methods

A systematic search was conducted in PubMed and Embase including three different aspects of intravitreal injection therapy: (1) diseases with intravitreal injections as treatment, (2) intravitreal injection, and (3) aspects of therapy adherence or therapy persistence. Data from identified quantitative studies were further extracted and grouped according to WHO criteria (condition, socio-economy, therapy, patient, and health system). The methodological quality of identified studies was graded. Identified qualitative studies (i.e., interviews) were descriptively analyzed and their findings narratively reported.

Results

Twenty-four publications were included. In 16 of those publications, a quantitative data analysis was conducted, analyzing factors associated with non-adherence. Worse visual acuity at baseline and unfavorable development of visual acuity, higher age, and greater distance to the treatment center were associated with non-adherence, while there was inconsistent evidence for an association of comorbidity. In qualitative studies, high follow-up/treatment burden, fear and anxiety, disappointed patient expectations, and lack of motivation to continue treatment were reported as reasons for non-persistence.

Conclusions

Knowledge of potential barriers in IVT treatment may improve adherence and potentially clinical results. Improvements can be achieved particularly in the healthcare complex (organizational improvements) and the “patient” complex by establishing realistic expectations. Recurrent education of the patient may be necessary.

Electronic supplementary material

The online version of this article (10.1007/s00417-020-04798-2) contains supplementary material, which is available to authorized users.

Critical analysis of techniques and materials used in devices, syringes, and needles used for intravitreal injections

Intravitreal injections have become the most commonly performed intraocular treatments worldwide. Because intravitreal injections may induce severe adverse events, such as infectious and noninfectious endophthalmitis, cataract, ocular hypertension, vitreous hemorrhage, or retinal detachment, appropriate awareness of the materials and techniques used are essential to reduce these sight-threatening complications. This review provides insights into the needles, syringes, silicone oil coating, sterilization methods, devices to assist intravitreal injections, scleral piercing techniques using needles, syringe handling, anesthesia, and safety issues related to materials and techniques. It is paramount that physicians be aware of every step involved in intravitreal injections and consider the roles and implications of all materials and techniques used. The ability to understand the theoretical and practical circumstances may definitely lead to state-of-the-art treatments delivered to patients. The most important practical recommendations are: choosing syringes with as little silicone oil as possible, or, preferably, none; avoiding agitation of syringes; awareness that most biologics (e.g., antiangiogenic proteins) are susceptible to changes in molecular properties under some conditions, such as agitation and temperature variation; understanding that improper materials and techniques may lead to complications after intravitreal injections, e.g., inflammation; and recognizing that some devices may contribute to an enhanced, safer, and faster intravitreal injection technique.

Corneal anesthesia associated with topical application of 2% lidocaine nonophthalmic gel to healthy canine eyes

OBJECTIVE

To assess the degree and duration of corneal anesthesia induced by topical application of 2% lidocaine gel to the healthy canine eye.

ANIMALS

Nineteen adult Beagles free of ocular abnormalities.

PROCEDURES

Baseline corneal touch threshold (CTT) was measured bilaterally with a Cochet-Bonnet aesthesiometer. The 2% lidocaine gel (0.1 mL) was applied to one eye, randomly assigned, and the same volume of a lubricant gel was applied to the opposite eye. The CTT measurements were repeated bilaterally within 1 minute, after drug application, and every 5 minutes, until the baseline corneal sensitivity was restored. The potential for local adverse effects was evaluated.

RESULTS

Complete desensitization of the cornea (CTT = 0) was achieved one minute after lidocaine gel application and was maintained during 25.3 ± 12.5 minutes. Overall, the corneal sensitivity was significantly decreased for 58.4 ± 16.6 minutes compared with baseline level. Minor and reversible punctate epithelial erosions of the cornea were observed in the two treatment groups and were attributed to the anesthetic effect and the aesthesiometry procedure.

CONCLUSIONS

In the current study, the 2% lidocaine gel provided a sustained, deep and well-tolerated corneal anesthesia in ophthalmically normal dogs.

Anesthesia for Intravitreal Injection: A Systematic Review

Background

The intravitreal injection has become one of the most commonly performed procedures in ophthalmology; however, there is no standardized approach to anesthesia during the procedure. The goal of this systematic review is to review approaches to anesthesia for intravitreal injection and look at comparative efficacy between these different anesthetics.

Methods

A systematic review of literature was performed in the MEDLINE, PubMed, Cochrane Library, and Clinicaltrials.gov databases using the key words “anesthesia”, “pain management”, and “intravitreal injection”. Of the initial 239 search matches, 30 articles were found to be relevant to the topic. 18 studies were excluded as they did not include primary data or did not include the visual analog scale as a primary outcome. The remaining 12 articles were assessed to look at the comparative efficacy of anesthesia and adverse events.

Results

The anesthesia techniques reported include topical methods such as anesthetic eyedrops, anesthetic gels, and anesthetic-soaked pledgets as well as subconjunctival injection of anesthetic. Ultimately, no single anesthetic or delivery mechanism was shown to be superior to the others in a statistically significant way and adverse events were largely insignificant. Limitations of these studies include relatively small sizes of the studies, as well as the lack of masking which may introduce bias.

Conclusion

In the current literature, no type of anesthetic method was found to be superior to another for intravitreal injection. Future studies in this area may lead to new insights into the efficacy of different forms of intravitreal anesthesia.

Which quadrant is less painful for intravitreal injection? A prospective study

PURPOSE

To evaluate the relationship between injection site and pain severity following intravitreal injection of bevacizumab (IVB).

DESIGN

Prospective, randomized, four-armed, clinical trial.

METHODS

The present study was a prospective, randomized, four-armed clinical trial, which included 1004 eyes from 1004 patients. Patients receiving IVB were randomly assigned into four groups: superotemporal (ST); superonasal (SN); inferotemporal (IT); and inferonasal (IN) injections. The visual analog scale (VAS) was used to assess pain. Primary study variables were the relationship between pain severity and injection site, number of previous injections, age, sex, and indication for injection. Secondary variables included best-corrected visual acuity (BCVA) and central macular thickness (CMT) changes 1 month post IVB.

RESULTS

Overall mean pain score was 2.86 ± 2.2. Indications for injection were diabetic macular edema (84.1%), neovascular age-related macular degeneration (7.7%), and macular edema secondary to retinal vein occlusion (8.2%). The mean VAS scores in the SN, IN, ST, and IT groups were 1.5 ± 1.7, 3 ± 2.3, 4 ± 2, and 3 ± 2.1, respectively. Pain severity was significantly correlated with injection site (p < 0.001) and sex (p < 0.001); females showed higher pain scores. A negative correlation existed between pain score and number of previous injections (p = 0.03). Pain severity was not associated with age (p = 0.659), lens status (p = 0.478), vitreous reflux (p = 0.648), or indication for injection (p = 0.390). No significant complications were observed.

CONCLUSIONS

ST quadrant was the most painful and SN quadrant was the least painful sites for IVB. Pain severity score was significantly associated with injection site, number of injections, and sex.

Complications of Intravitreous Injections in Patients with Diabetes

Intravitreous injections are presently the second most frequently performed ophthalmic procedure and the most common vitreoretinal procedure. In diabetic patients, intravitreous injections are frequently performed for the treatment of center-involved diabetic macular edema, proliferative diabetic retinopathy, or other co-existing retinal vascular disease. Diabetic patients may be at higher risk of adverse events compared to non-diabetic individuals, given frequent systemic comorbidities, such as cardiovascular and renal disease and increased susceptibility to infection. This review highlights the potential complications and safety considerations in intravitreous injections in patients with diabetes.

Pilot Study Comparing Topical Anesthetic Agents in Pterygium Surgery: Subconjunctival Injection Versus 2% Lidocaine Gel Versus 5% Lidocaine Gel

PURPOSE

To compare the efficacy of different concentrations of topical lidocaine gel with standard subconjunctival anesthesia.

METHODS

This was a prospective randomized controlled pilot study with 3 different groups. Group SC received subconjunctival lidocaine and proparacaine drops as needed during surgery. Group L2 received 2% lidocaine gel and group L5 received 5% lidocaine gel. Both lidocaine gel groups could receive another gel dose as needed during the procedure. The primary outcome was pain, which was experienced during and after surgery. The assessment was done using a 10-point linear analog scale at predetermined stages of surgery (1-first incision, 2-pterygium body excision, 3-conjunctival suturing, 4-immediate postoperative period after patching, and 5-assessment by a trained nurse in the absence of a surgeon after operation).

RESULTS

We enrolled 45 consecutive patients who underwent primary pterygium surgery. Statistical significance between groups was found in mean pain at administration (2.2 vs. 0.4 vs. 0.0 in SC, L2, and L5 groups, respectively, with P < 0.05). The number of reapplications of anesthetic drops did not differ between the groups. We found a correlation between reapplication of the anesthetic and pain at administration and duration of the procedure.

CONCLUSIONS

We demonstrated that the use of lidocaine gel at concentrations of 2% and 5% in pterygium surgery was as effective as subconjunctival injection of lidocaine in reducing intraoperative and postoperative pain, producing significantly less pain during initial administration of the anesthetic.

Patient pain during intravitreal injections under topical anesthesia: a systematic review

Background

Intravitreal injection (IVI) is a very common vitreoretinal procedure, and multiple injections are often required per patient. This systematic review was conducted to evaluate the effectiveness of various local anesthetic techniques in reducing pain during injection.

Methods

A systematic review was conducted based on searches of Cochrane, LILACS, PubMed, Scopus, Web of Science, and the gray literature (Google Scholar). The end search date was February 19, 2016, across all databases. We classified pain by converting visual analog scale (VAS) scores (0–100 mm) into Jensen’s classification levels: 0–4, no pain; 5–44, mild pain; 45–74, moderate pain; and 75–100, severe pain. An intervention was considered clinically significant when pain score change was >12 mm on a 100-mm scale.

Results

Eight studies out of 23 met the eligibility criteria. The total number of patients was 847. Most studies (5/8 [62.5%]) were at unclear risk of bias because of unclear randomization, thus providing only moderate evidence to this review. The anesthetic techniques included eye drops with proparacaine, tetracaine or cocaine, a lidocaine pledget or gel, and subconjunctival injection of 2% lidocaine or 0.75% levobupivacaine. No study comprised all of the techniques. Pain was mild (VAS scores, 5–44 mm) regardless of anesthetic technique. A clinically significant intervention (pain score change >12 mm) was found for only one study comparing proparacaine drops, lidocaine gel, and subconjunctival lidocaine; in that study, a subconjunctival injection of 2% lidocaine provided the greatest pain reduction. A meta-analysis was not possible due to study heterogeneity.

Conclusions

Patient pain during IVI under topical anesthesia is mild regardless of anesthetic technique. A subconjunctival injection of 2% lidocaine could be an option for highly sensitive patients. However, with moderate level of evidence, no single anesthetic technique could be defined as the best option for IVI.

Electronic supplementary material

The online version of this article (doi:10.1186/s40942-017-0076-9) contains supplementary material, which is available to authorized users.

Intraoral Vacuum of Breast-Feeding Newborns Within the First 24 Hr

Objectives:

To explore whether newborns born via Cesarean section have a weaker intraoral vacuum compared with those born vaginally and to determine whether a weaker intraoral vacuum is related to a delayed onset of lactation.

Methods:

For this prospective cohort study, 71 mother–infant dyads were enrolled and divided into birthing groups, vaginal or Cesarean. The newborn intraoral vacuum was measured via a tube placed alongside the nipple and connected to a pressure sensor during a breast-feeding session within the first 24 hr after birth. Onset of lactation was confirmed by maternal perception of breast fullness. The intraoral vacuum and its relationship with the onset of lactation were analyzed. Results: After adjustment for confounding factors, the peak intraoral vacuum was −19.50 kPa in the vaginal group, which was significantly stronger than the −13.78 kPa in the Cesarean group ( p = .005). Additionally, the baseline intraoral vacuum in the vaginal group (−2.35 kPa) was significantly stronger than that in the Cesarean group (−1.18 kPa; p = .022). Strength of the newborn intraoral vacuum was associated with the time of onset of maternal lactation.

Conclusion:

Cesarean section may weaken newborns’ intraoral vacuum within the first 24 hr after birth. Stronger intraoral vacuum was related to earlier onset of lactation. Early intervention aimed at the weaker intraoral vacuum should be provided to promote the onset of lactation.

Comparative Study Between Lidocaine Gel 2% and 5% for Ophthalmic Procedures

PURPOSE

To compare same-day pain control and safety of 2 different anesthetic gels utilizing 5% and 2% lidocaine gel. Main outcome is to determine whether 5% lidocaine gel is more effective in decreasing pain during conjunctival clamping compared to 2% lidocaine gel 5 and 10 min after gel application.

METHODS

This is a prospective, randomized double-blind clinical trial. Patients were randomized to receive 2% or 5% lidocaine gel in each eye. Discomfort during the gel instillation and pain during conjunctival clamping 5 and 10 min after gel application were compared. Extent of corneal conjunctival staining was graded according to the Oxford scale.

RESULTS

Eighty eyes of 40 patients were enrolled. The groups were similar in gender, with a mean age of 48 ± 16.26 years. The 5% lidocaine gel resulted in higher discomfort during initial instillation (P = 0.092), however, the pain during conjunctival clamping was lower in the 5% lidocaine gel eyes (P = 0.564) in both 5 and 10 min later (P < 0.001). The majority of patients (80%) had no corneal conjunctival dye staining. The tear break-up time was not statistically different after lidocaine gel 2% (20.35 ± 7.37 s) and lidocaine 5% (19.75 ± 7.00 s).

CONCLUSION

Five percent and 2% lidocaine gel have similar efficacy controlling pain 5 min after instillation, however, 5% lidocaine gel appears to be more effective with a longer duration of action, without corneal toxicity. There was no corneal toxicity noted with either concentration.