Peribulbar anesthesia for cataract surgery: effect of lidocaine warming and alkalinization on injection pain, motor and sensory nerve blockade

A Bilayer Microneedle for Modulated Sequential Release of Adrenaline and Lidocaine for Prolonged Local Anesthesia

Chronic pain emerges as a major global health issue, significantly impacting individuals' health and quality of life. In this study, we designed a bilayer microneedle loaded with lidocaine nanocomposites in the inner layer and adrenaline (Adr) in the outer layer (HCP MNs) for modulated sequential release to achieve prolonged local anesthesia. The obtained HCP MNs featured an intact structure with adequate mechanical strength for efficient skin penetration. The bilayer structure of MNs was evidenced by loading two fluorescent dyes in each layer. Furthermore, these HCP MNs were capable of inducing rapid as well as prolonged local anesthetic effects in guinea pigs. Hence, the bilayer MN coloaded with Adr and lidocaine nanocomposite serves as a promising transdermal delivery platform for chronic pain management.

Effect of warming local anesthesia solutions before intraoral administration in dentistry: a systematic review

BACKGROUND

The aim of the present systematic review was to evaluate and compare the efficacy of warmed and unwarmed local anesthesia solutions in reduction of pain during intraoral injection administration.

METHODS

PubMed, Ovid SP, and Cochrane Central Register of Controlled Trials were searched from publication years 1990 to 2020 with relevant MeSH terms. Studies were screened by titles and abstracts, followed by full-texts evaluation of the included studies.

RESULTS

A total of four studies were included in the systematic review. Outcomes evaluated were subjective and objective pain during administration of the warmed local anesthesia solution in comparison with the unwarmed local anesthesia solution. Among the four studies that evaluated the self-reported pain score, three studies showed significantly lower pain scores associated with warmed local anesthesia. Only two studies evaluated the observed pain score, and both of them reported a significantly lower pain reaction with the warmed local anesthesia solution.

CONCLUSION

Within the limits of this systematic review, warming the local anesthesia solution to body temperature (37℃) before administration seemed to reduce the discomfort during intraoral local anaesthesia administration, and more high-quality studies should be carried out to validate the same.

Effect of warming anesthetic on pain perception during dental injection: a split-mouth randomized clinical trial

BACKGROUND

The purpose of this study is to determine the effectiveness of warming anesthesia on the control of the pain produced during the administration of dental anesthesia injection and to analyze the role of Transient Receptor Potential Vanilloid-1 nociceptor channels in this effect.

PATIENTS AND METHODS

A double-blind, split-mouth randomized clinical trial was designed. Seventy-two volunteer students (22.1±2.45 years old; 51 men) from the School of Dentistry at the Universidad Austral de Chile (Valdivia, Chile) participated. They were each administered 0.9 mL of lidocaine HCl 2% with epinephrine 1:100,000 (Alphacaine®) using two injections in the buccal vestibule at the level of the upper lateral incisor teeth. Anesthesia was administered in a hemiarch at 42°C (107.6°F) and after 1 week, anesthesia was administered by randomized sequence on the contralateral side at room temperature (21°C-69.8°F) at a standardized speed. The intensity of pain perceived during the injection was compared using a 100 mm visual analog scale (VAS; Wilcoxon test p<0.05).

RESULTS

The use of anesthesia at room temperature produced an average VAS for pain of 35.3±16.71 mm and anesthesia at 42°C produced VAS for pain of 15±14.67 mm (p<0.001).

CONCLUSION

The use of anesthesia at 42°C significantly reduced the pain during the injection of anesthesia compared to its use at room temperature during maxillary injections. The physiological mechanism of the temperature on pain reduction could be due to a synergic action on the permeabilization of the Transient Receptor Potential Vanilloid-1 channels, allowing the passage of anesthetic inside the nociceptors.

Pain Levels after Local Anaesthetic with or without Hyaluronidase in Carpal Tunnel Release: A Randomised Controlled Trial

Purpose. Hyaluronidase is an enzyme that temporarily liquefies the interstitial barrier, allowing easy dispersal of local anaesthetic through cleavage of tissue planes. This prospective, blinded, randomised controlled study investigates the utility of adding hyaluronidase to local anaesthetic in the setting of carpal tunnel release. Methods. 70 consecutive carpal tunnel release patients were recruited and randomised into a control group only receiving local anaesthetic and a hyaluronidase group receiving both hyaluronidase and local anaesthetic. Pain scores were rated using the visual analogue scale (VAS) by patients immediately after local anaesthetic injection and again immediately after the carpal tunnel release. Results. Preoperative VAS scores, taken after local anaesthetic injection, were greater than postoperative VAS scores. Postoperative VAS scores were significantly lower in the hyaluronidase group and tourniquet times were significantly shorter in the hyaluronidase group. Conclusion. Hyaluronidase addition to local anaesthetic in carpal tunnel release resulted in significant reductions in operative time and pain immediately after operation.

WITHDRAWN: Adjusting the pH of lidocaine for reducing pain on injection

May 2015

This review was originally published in 2010 and at that time complied with Cochrane’s Commercial Sponsorship Policy. The Commercial Sponsorship policy was updated in 2014 (http://community.cochrane.org/organisational‐policy‐manual/appendix‐5‐commercial‐sponsorship‐policy ). This review is no longer compliant with that policy.

The non conflicted members of the original team of authors have decided not to update the review. We have therefore decided to withdraw the review and seek new authors to update it

The editorial group responsible for this previously published document have withdrawn it from publication.

Ophthalmic regional anaesthesia: A review and update

Local anaesthetic techniques are increasingly popular for ophthalmic surgery. It is now being provided mainly by anaesthesiologists and varies from an akinetic injection technique to a non-akinetic topical technique. Each technique has its own risk/benefit profile, and proven to be highly successful if performed correctly. The choice of the technique should be individualized based upon specific needs of the patient, the nature and extent of eye surgery, and the anaesthesiologist's and surgeon's preferences and skill. This review article attempts to outline the orbital anatomy, discuss the commonly used agents, current method of pre-operative preparation, available clinical techniques and their inherent complications.

Systematic review and meta-analysis of the effect of warming local anesthetics on injection pain

STUDY OBJECTIVE

Local anesthetics are the main class of analgesics used for pain management during laceration repair and other minor surgeries; however, they are administered by injection, which is painful. Warming local anesthetics has been proposed as a cost-free intervention that reduces injection pain. A systematic review of the effectiveness of this technique has not yet been undertaken. We determine the effectiveness of warming local anesthetics to reduce pain in adults and children undergoing local anesthetic infiltration into intradermal or subcutaneous tissue.

METHODS

We used published articles from MEDLINE (1950 to June 2010), EMBASE (1980 to June 2010), CINAHL (1982 to June 2010), the Cochrane Library (second quarter 2010), International Pharmaceutical Abstracts (1970 to June 2010), and ProQuest Dissertations and Theses database (1938 to June 2010). We included studies with randomized or pseudorandomized designs and healthy subjects or patients receiving subcutaneous or intradermal injection of local anesthetics that were warmed (body temperature) or not (room temperature). Studies of regional anesthesia and intraarticular, spinal, or periorbital administration of local anesthetics were excluded. Data were extracted onto predesigned forms and verified by 2 reviewers. Quality was assessed with the Cochrane risk of bias tool. The primary outcome was self-reported pain as assessed by a visual analog or numeric rating scale. Data were combined with mean differences with 95% confidence intervals (CIs) by using a random-effects model.

RESULTS

Twenty-nine studies were retrieved for close examination and 19 studies met inclusion criteria. A total of 18 studies with 831 patients could be included in a meta-analysis. Seventeen studies had an unclear risk of bias and 1 had a high risk of bias. A mean difference of -11 mm (95% CI -14 to -7 mm) on a 100-mm scale was found in favor of warming local anesthetics. Subgroup analysis of 8 studies investigating the effect of warming on buffered local anesthetics yielded similar results: -7 mm (95% CI -12 to -3 mm).

CONCLUSION

Warming local anesthetics leads to less pain during injection and therefore should be done before administration.

Adjusting the pH of lidocaine for reducing pain on injection

BACKGROUND

Lidocaine administration produces pain due to its acidic pH.

OBJECTIVES

The objective of this review was to determine if adjusting the pH of lidocaine had any effect on pain resulting from non-intravascular injections in adults and children. We tested the hypothesis that adjusting the pH of lidocaine solution to a level closer to the physiologic pH reduces this pain.

SEARCH STRATEGY

We searched the Cochrane Central Register of Controlled Trials (CENTRAL) (The Cochrane Library, to June 2010); Ovid MEDLINE (1966 to June 2010); EMBASE (1988 to June 2010); LILACS (1982 to June 2010); CINAHL (1982 to June 2010); ISI Web of Science (1999 to June 2010); and abstracts of the meetings of the American Society of Anesthesiologists (ASA). We checked the full articles of selected titles. We did not apply any language restrictions.

SELECTION CRITERIA

We included double-blinded, randomized controlled trials that compared pH-adjusted lidocaine with unadjusted lidocaine. We evaluated pain at the injection site, satisfaction and adverse events. We excluded studies in healthy volunteers.

DATA COLLECTION AND ANALYSIS

We separately analysed parallel-group and crossover trials; trials that evaluated lidocaine with or without epinephrine; and trials with pH-adjusted lidocaine solutions < 7.35 and ≥ 7.35. To explain heterogeneity, we separately analysed studies with a low and higher risk of bias due to the level of allocation concealment; studies that employed a low and a higher volume of injection; and studies that used lidocaine for different types of procedures.

MAIN RESULTS

We included 23 studies of which 10 had a parallel design and 13 were crossover studies. Eight of the 23 studies had moderate to high risk of bias due to the level of allocation concealment.Pain associated with the infiltration of buffered lidocaine was less than the pain associated with infiltration of unbuffered lidocaine in both parallel and crossover trials. In the crossover studies, the difference was -1.98 units (95% confidence interval (CI) -2.62 to -1.34) and in the parallel-group studies it was -0.98 units (95% CI -1.49 to -0.47) on a 0 to 10 scale. The magnitude of the pain decrease associated with buffered lidocaine was larger when the solution contained epinephrine. The risk of bias, volume of injection, and type of procedure failed to explain the heterogeneity of the results.Patients preferred buffered lidocaine (odds ratio 3.01, 95% CI 2.19 to 4.15). No adverse events or toxicity were reported.

AUTHORS' CONCLUSIONS

Increasing the pH of lidocaine decreased pain on injection and augmented patient comfort and satisfaction.