Local anesthetic toxicity: acute and chronic management

Pharmacokinetics of single dose levobupivacaine after peri-incisional subcutaneous infiltration in anaesthetized domestic pigs

Increasing use of pigs as models in translational research, and growing focus on animal welfare are leading to better use of effective analgesics and anaesthetics when painful procedures are performed. However, there is a gap in basic knowledge such as pharmacokinetics of different anaesthetics in these species. The main objective of our study was to determine the pharmacokinetics of levobupivacaine in domestic pigs. Twelve female grower pigs weighing 31.17 ± 4.6 kg were subjected to general anaesthesia and experimental surgery, at the end of which they received 1 mg/kg levobupivacaine via peri-incisional subcutaneous infiltration. Plasma samples were collected before administration of levobupivacaine and at 0.5, 1, 2, 4, 8, 12, 24 and 48 h thereafter. Concentrations of levobupivacaine were determined by liquid chromatography coupled with tandem mass spectrometry. Following single dose of levobupivacaine, all animals had measurable plasma concentrations 0.5 h after drug administration, with most peak concentrations observed at the 1-h time point. In all 12 animals, levobupivacaine was below the limit of quantification 48 h after drug administration. The mean maximum plasma concentration, area under the curve and half-life were determined to be 809.98 μg/l, 6552.46 μg/l h and 6.25 h, respectively. Plasma clearance, volume of distribution and weight-normalized volume of distribution were 4.41 l/h, 35.57 l and 1.23 l/kg, respectively. Peak plasma concentrations in our study were well below concentrations that were found to produce toxicity in pigs.

Emergency Medicine Case Study on Local Anesthetic Systemic Toxicity

The purpose of this case study on local anesthetic systemic toxicity (LAST), a potentially life-threatening complication of local anesthetic, is to ensure that emergency nurse practitioners (ENPs) are knowledgeable on this disease process. Local anesthetics are used frequently, often daily, by ENPs, as well as multiple other health care providers for various procedures. They should be knowledgeable of the steps to resuscitate a patient who may have severe LAST. This case study reviews the emergency management of LAST, including pharmacologic treatment, deviations from routine advanced resuscitative guidelines, and disposition of the patient upon successful resuscitation. Additionally, risk assessment and clinical manifestations will be discussed. After reviewing this case study, ENPs should be able to recognize the presentation of LAST and provide emergent management to reduce complications, comorbidities, and death.

Anesthesia Techniques for Harvesting via Follicular Unit Excision

Follicular unit excision (FUE) is one of the established techniques for harvesting donor hair for hair transplantation. Traditionally, hair restoration surgery is performed using local anesthesia, although some surgeons use general anesthesia for the procedure. Normally, local anesthesia is coupled with light oral sedation to make the procedure more comfortable for patients. Techniques such as "ring block" or nerve blocks are common and effective for scalp anesthesia. Due to its simplicity, adequate pain control and safety, ring blocks are typically used for FUE donor harvesting, reserving nerve blocks only to patients who cannot be adequately anesthetized with the ring block. Using the correct technique for application of local anesthesia can dramatically decrease the pain associated with it and create a comfortable and easy experience for the patient.

Knowledge, Attitudes and Practices Regarding Use of Local Anaesthetics Among Non-Anaesthesia Healthcare Professionals at Mulago National Referral Hospital

Introduction

Local anaesthetics (LA) are commonly used in dental and surgical emergency wards by both anaesthesia professionals and non-anaesthesia professionals. Anecdotal evidence shows that non-anaesthesia health-care professionals do not monitor vital signs during the use of local anaesthesia, and there are no standard hospital guidelines on the use of LA and management of LA toxicity by non-anaesthesia professionals.

Purpose

This study sought to assess the knowledge, attitudes and practices regarding local anaesthetic use among non-anaesthesia health-care professionals at Mulago National Referral Hospital.

Patients and Methods

This was a cross-sectional study that utilized a quantitative research approach. The sample size of the study was 43 non-anaesthesia healthcare professionals from the casualty and surgical outpatient wards and Mulago dental ward. Data was collected using a questionnaire and analyzed using STATA 15.

Results

Overall, 66.67% of the Specialist, 76.47% of the senior house officers, 100% of medical officers, and 80% of the clinical orthopedic house officers had unsatisfactory levels of knowledge in Mulago casualty and surgical outpatient wards. 20% of the specialist and 16.67% of the senior house officers had unsatisfactory levels of knowledge in Mulago dental ward. 87.5% of the non-anaesthesia health-care professionals do not give a test dose on a routine basis in Mulago casualty and surgical outpatient wards. A total of 63.64% of the non-anaesthesia healthcare professionals in Mulago dental ward do not sterilize the site of injection.

Conclusion

Non-anaesthesia health-care professionals had unsatisfactory levels of knowledge, somewhat good practices, and negative attitudes toward LA use.

An overview of local anesthetics in over-the-counter products

Over-the-counter (OTC) local anesthetics have historically been used to alleviate pain in several common conditions including toothache and sore throat. With a rise in chronic conditions and an aging population, there has been an increase in associated chronic pain-related disorders. Individuals with chronic pain often seek OTC treatments for quick and accessible pain relief. There are several common OTC local anesthetics, including benzocaine, lidocaine, and dibucaine, which are readily available to patients in several formulations. In order to appropriately advise patients on the use of local anesthetics, it is important to understand their key characteristics, including the mechanism of action, clinical properties, pharmacokinetics, clinical applications, and adverse reactions, which may occur.

Crocin alleviates neurotoxicity induced by bupivacaine in SH-SY5Y cells with inhibition of PI3K/AKT signaling

BACKGROUND

Bupivacaine, a common local anesthetic, can cause neurotoxicity and permanent neurological disorders. Crocin has been widely reported as a potential neuroprotective agent in neural injury models.

OBJECTIVE

The aim of this study was to investigate the role and regulatory mechanism of crocin underlying bupivacaine-induced neurotoxicity.

METHOD

Human neuroblastoma SH-SY5Y cells were treated with bupivacaine and/or crocin for 24 h, followed by detecting cell viability using 3-(4,5-dimethylthiazol-2-yl)-2, 5-diphenyltetrazolium bromide assay. The effect of crocin or bupivacaine on SH-SY5Y cell proliferation was measured by Ki67 immunofluorescence assay. The levels of apoptosis-related proteins and the markers in the PI3K/Akt signaling pathway were examined using western blot analysis. The activities of caspase 3, catalase (CAT), superoxide dismutase (SOD), malondialdehyde (MDA) and glutathione peroxidase (GSH-Px) were tested using respective commercial assay kits. Flow cytometry analysis was executed for detecting SH-SY5Y cell apoptosis.

RESULT

Crocin attenuated bupivacaine-induced neurotoxicity in SH-SY5Y cells. Meanwhile, crocin inhibited SH-SY5Y cell apoptosis induced by bupivacaine via repressing the activity of caspase-3, reducing Bax expression, and elevating Bcl-2 expression. Moreover, crocin mitigated oxidative stress in SH-SY5Y cells by increasing the content of CAT, SOD, GSH-Px and reducing the content of MDA. Additionally, crocin protected against bupivacaine-induced dephosphorylation of Akt and GSK-3β. The protective effects of crocin against bupivacaine-induced neurotoxicity in SH-SY5Y cells were counteracted by the Akt inhibitor.

CONCLUSION

These results suggested that crocin may exert a neuroprotective function by promoting cell proliferation and suppressing apoptosis and oxidative stress in SH-SY5Y cells. Thus, crocin might become a promising drug for the treatment of bupivacaine-induced neurotoxicity.

The Effectiveness of Ultrasound-Guided, Continuous, Bilateral Erector Spinae Plane Block in Perioperative Pain Management of Patients Undergoing Colorectal Surgery: A Randomized, Controlled, Double Blind, Prospective Trial

Open and laparoscopic colorectal surgeries, while essential in the management of various colorectal pathologies, are associated with significant postoperative pain. Effective perioperative pain management strategies remain an anesthesiologic challenge. The erector spinae plane block (ESPB), a novel peripheral nerve block, has gained attention for its potential in providing analgesia for a wide variety of surgeries. This study aimed to evaluate the effectiveness of continuous, bilateral ultrasound-guided ESPB in perioperative pain management of patients undergoing colectomy. This prospective, randomized, controlled, double-blind trial included 40 adult patients scheduled for elective open or laparoscopic colectomy. Patients undergoing open colectomy as well as patients undergoing laparoscopic colectomy were randomly allocated into two groups: the ESPB group (n = 20) and the control group (n = 20). All patients received preoperatively ultrasound-guided, bilateral ESPB with placement of catheters for continuous infusion. Patients in the ESPB group received 0.375% ropivacaine, while patients in the control group received sham blocks. All patients received standardized general anesthesia and multimodal postoperative analgesia. Pain scores, perioperative opioid consumption, and perioperative outcomes were assessed. Patients in the ESPB group required significantly less intraoperative (p < 0.001 for open colectomies, p = 0.002 for laparoscopic colectomies) and postoperative opioids (p < 0.001 for open colectomies, p = 0.002 for laparoscopic colectomies) and had higher quality of recovery scores on the third postoperative day (p = 0.002 for open and laparoscopic colectomies). Patients in the ESPB group did not exhibit lower postoperative pain scores compared to those in the control group (p > 0.05 at various time points), while patients in both groups reported comparable satisfaction scores with their perioperative pain management (p = 0.061 for open colectomies, and p = 0.078 in laparoscopic colectomies). No complications were reported. ESPB is a novel and effective strategy in reducing perioperative opioid consumption in patients undergoing colectomy. This technique, as part of a multimodal analgesic plan and enhanced recovery after surgery protocols, can be proven valuable in improving the comfort and satisfaction of patients undergoing colorectal surgery.

Anti-Adhesive Resorbable Indomethacin/Bupivacaine-Eluting Nanofibers for Tendon Rupture Repair: In Vitro and In Vivo Studies

The treatment and surgical repair of torn Achilles tendons seldom return the wounded tendon to its original elasticity and stiffness. This study explored the in vitro and in vivo simultaneous release of indomethacin and bupivacaine from electrospun polylactide-polyglycolide composite membranes for their capacity to repair torn Achilles tendons. These membranes were fabricated by mixing polylactide-polyglycolide/indomethacin, polylactide-polyglycolide/collagen, and polylactide-polyglycolide/bupivacaine with 1,1,1,3,3,3-hexafluoro-2-propanol into sandwich-structured composites. Subsequently, the in vitro pharmaceutic release rates over 30 days were determined, and the in vivo release behavior and effectiveness of the loaded drugs were assessed using an animal surgical model. High concentrations of indomethacin and bupivacaine were released for over four weeks. The released pharmaceutics resulted in complete recovery of rat tendons, and the nanofibrous composite membranes exhibited exceptional mechanical strength. Additionally, the anti-adhesion capacity of the developed membrane was confirmed. Using the electrospinning technique developed in this study, we plan on manufacturing degradable composite membranes for tendon healing, which can deliver sustained pharmaceutical release and provide a collagenous habitat.

Efficacy of the erector spinae plane block with sedation for unilateral biportal endoscopic spine surgery and comparison with other anesthetic methods

BACKGROUND

Erector spinae plane block (ESPB) is a new regional anesthesia. Unilateral biportal endoscopic (UBE) spine surgery, a minimal invasive technique, has been performed under not only general anesthesia (GA) but regional anesthesia including spinal anesthesia (SA). The aims of this study were to evaluate the efficacy of ESPB with sedation for UBE lumbar decompression and compare it with GA and SA.

METHOD

A retrospective age matched case-control study design was performed. Three groups (20 patients in each group) of patients who underwent UBE lumbar decompressions under each anesthetic method (GA, SA, or ESPB) were formed. The total anesthesia time excluding operation time, postoperative analgesia effects, hospital days, and complications related to anesthetic methods were evaluated.

RESULTS

In the ESPB group, all the operations were performed without change of anesthetic methods and without anesthetic complications. But there were no anesthetic effects in the epidural space, which resulted in additional intravenous fentanyl usage. The mean of time from initiation of anesthesia to completion of surgical preparation was 23.3 ± 4.7 min in the ESPB group, which was shorter than 32.3 ± 10.8 min in the GA (p value = 0.001) or 33.3 ± 6.7 min in the SA group (p < 0.001). The proportion of patients requiring first rescue analgesia within 30 min was 30% in the ESPB group, which was lower than 85% in the GA (p < 0.001), but no significant different with 10% in the SA (p = 0.11). The mean of total hospital days in the ESPB was 3.0 ± 0.8, shorter than 3.7 ± 1.8 in the GA (p = 0.02) or 3.8 ± 1.1 in the SA group (p = 0.01). There was no case of postoperative nausea and vomiting in the ESBB even without prophylactic antiemesis.

CONCLUSION

ESPB with sedation is a viable anesthetic option for UBE lumbar decompression.

A Hematoma Block in the Wrist for a Displaced Distal Radius Fracture Induces Systemic Neurological Symptoms: A Case Report

Hematoma blocks are considered a relatively simple, safe, and effective technique in the acute setting to provide sufficient anesthesia and allow for closed reduction of displaced distal radius fractures. Complications associated with the utilization of local anesthetics in this setting are rare. We present the case of a patient who had a hematoma block in the wrist and developed short-term systemic neurologic complications likely secondary to systemic absorption of 20 mL of 1% lidocaine without epinephrine via the cancellous bone channels.

LC-MS/MS quantification of ropivacaine and local analgesic and adverse effects of Long-acting Ropivacaine Injection based on pharmacokinetic-pharmacodynamic modelling in Bama minipigs

The local analgesic efficacy and adverse effects of a new Long-acting Ropivacaine formulation were examined based on pharmacokinetic-pharmacodynamic (PK-PD) modelling in Bama minipigs. 24 Bama minipigs, 12 males and 12 females, were randomly and equally divided into the following treatment groups: normal saline injection, drug vehicle injection, Long-acting Ropivacaine Injection and Ropivacaine Hydrochloride Injection. After routine disinfection, a skin incision about 3 cm long and 3 cm deep was produced in the leg of each pig, and mechanical withdrawal threshold (MWT) measured at various times pre- and post-injection as an index of analgesia against incision pain. Plasma ropivacaine concentrations were also measured at the same times using a novel liquid chromatography-tandem mass spectroscopy (LC-MS/MS) method. Minipigs were sacrificed 24 h post-injection and hearts collected for drug concentration measurements by LC-MS/MS. The LC-MS/MS method demonstrated high sensitivity, linearity and precision. The Long-acting Ropivacaine formulation produced a longer analgesic effect (∼12 h) at a lower plasma concentration than Ropivacaine Hydrochloride (∼4h), suggesting a better side-effects profile. A PK-PD model revealed a direct relationship between plasma ropivacaine concentration and MWT, with peak analgesia at about 1000 ng/mL and behaved good prediction ability. Long-acting Ropivacaine Injection is a superior local anaesthetic-analgesic treatment due to longer-lasting efficacy at lower concentrations compared to Ropivacaine Hydrochloride, which will reduce the risk of side effects such as cardiotoxicity.

Neurological pain relief interventional radiology procedures

Neurological interventions have taken on a significant role in interventional radiology (IR) practice. Indications fall under three main categories: (1) intraprocedural pain management, (2) cancer pain palliation, and (3) chronic non-cancer pain control. Short-term regional anaesthesia can be achieved with local anaesthetics, while longer-term pain control can be attained with radiofrequency neuromodulation (pulsed or otherwise) or thermal/chemical neurolysis. This review article summarises the therapeutic options, applications, and techniques of commonly used peripheral nerve and plexus interventions in IR.

Hepatic Hilar Nerve Block for Adjunctive Analgesia during Percutaneous Thermal Ablation of Hepatic Tumors: A Retrospective Analysis

PURPOSE

To determine whether hepatic hilar nerve block techniques reduce analgesic and sedation requirements during percutaneous image-guided thermal ablation of hepatic tumors.

MATERIALS AND METHODS

A single-center retrospective cohort analysis was performed of 177 patients (median age, 67 years; range, 33-86 years) who underwent percutaneous image-guided thermal ablation of liver tumors. All patients were treated utilizing local anesthetic and moderate sedation between November 2018 and November 2021 at a tertiary level hospital, with or without the administration of a hepatic hilar nerve block. Univariable and multivariable linear regression analyses were performed to determine the relationship between the administration of the hilar nerve block and fentanyl and midazolam dosages.

RESULTS

A total of 114 (64%) patients received a hilar nerve block in addition to procedural sedation, and 63 (36%) patients received procedural sedation alone. There were no significant differences in the baseline demographic and tumor characteristics between the cohorts. The procedure duration was longer in the hilar block cohort than in the unblocked cohort (median, 95 vs 82 minutes; P = .0012). The technical success rate (98% in both the cohorts, P = .93) and adverse event rate (11% vs 3%, P = .14) were not significantly different between the cohorts. After adjusting for patient and tumor characteristics, ablation modality, and procedure and ablation durations, hilar nerve blocks were associated with lower fentanyl (-18.4%, P = .0045) and midazolam (-22.7%, P = .0007) dosages.

CONCLUSIONS

Hepatic hilar nerve blocks significantly decrease the fentanyl and midazolam requirements during thermal ablation of hepatic tumors, without a significant change in the technical success or adverse event rates.

Dexmedetomidine protects against Ropivacaine-induced neuronal pyroptosis via the Nrf2/HO-1 pathway

Dexmedetomidine (DEX) has been demonstrated to protect against ropivacaine (Ropi)-induced neuronal damages. This study was conducted to explore the protective role of DEX in Ropi-induced neuronal pyroptosis and provide a strategy to eliminate Ropi-induced neurotoxicity. The impacts of different concentrations of Ropi and DEX on neurotoxicity in SK-N-SH cells were evaluated by cell counting kit-8 assay and lactic dehydrogenase assay kits. Levels of nuclear factor erythroid 2-related factor 2 (Nrf2), heme oxygenase 1 (HO-1), NLR family pyrin domain containing 3 (NLRP3), cleaved Caspase-1, cleaved N-terminal gasdermin D, interleukin (IL)-1β, and IL-18 were measured by real-time quantitative PCR, Western blotting, and enzyme linked immunosorbent assay. The Nrf2 level after nuclear/cytoplasmic separation was quantified. SK-N-SH cells were treated with si-Nrf2, Nigericin (NLRP3 activator), and Zinc Protoporphyrin (HO-1 inhibitor) to validate the mechanism. Ropi reduced SK-N-SH cell viability in a concentration- and time-dependent manner. DEX treatment alleviated Ropi-induced toxicity and inhibited pyroptosis. Ropi increased the expression levels of Nrf2 and HO-1, and DEX further enhanced the increases and promoted Nrf2 nuclear translocation. Nrf2/HO-1 inhibition or NLRP3 activation both neutralized the inhibitory role of DEX in Ropi-induced pyroptosis of SK-N-SH cells. Overall, DEX promoted the Nrf2/HO-1 pathway to inhibit NLRP3 expression, thus alleviating Ropi-induced neuronal pyroptosis.

Enhanced Recovery After Aesthetic Breast Surgery Under Sedation, Intercostal Block and Tumescent Anaesthesia: A Prospective Cohort Study of the Early Postoperative Phase

BACKGROUND

Comfort and recovery are major concerns of patients seeking aesthetic surgery. This study aimed to assess postoperative pain and recovery after outpatient breast surgery under sedation, intercostal block, and local anaesthesia.

METHODS

This prospective cohort study included all consecutive patients who underwent aesthetic breast surgery between April 2021 and August 2022. Epidemiological data, anaesthesia, pain, and patients' satisfaction were systematically assessed with standardized self-assessment questionnaires.

RESULTS

Altogether, 48 patients [median (IQR) age: 30 (36-25)] were included. The most frequent surgery was mastopexy. 69% of surgeries involved additional procedures. The mean intercostal block and local anaesthesia time was 15 min. Patients received a median (IQR) of 19 (34-2) mg/kg lidocaine and 2.3 (2.5-2.0) mg/kg ropivacaine. The median (IQR) consumption of propofol and alfentanil was, respectively, 4.89 (5.48-4.26) mg/kg/h and 0.27 (0.39-0.19) µg/kg/min. No conversion to general anaesthesia or unplanned hospital admission occurred. Patients were discharged after a median (IQR) of 2:40 (3:43-1:58) hours. Within the first 24 postoperative hours, 17% required once an antiemetic medication and 38% an opioid. Patients were very satisfied with the anaesthesia and 90% of the patients had not wished more analgesia in the first 24 h.

CONCLUSIONS

Aesthetic breast surgery under sedation, intercostal block, and tumescent anaesthesia can safely be performed as an ambulatory procedure and is associated with minimal intra- and postoperative opioid consumption and high patient satisfaction. These data may be used to inform patients and clinicians and improve the overall quality of care.

LEVEL OF EVIDENCE IV

This journal requires that authors assign a level of evidence to each article. For a full description of these Evidence-Based Medicine ratings, please refer to the Table of Contents or the online Instructions to Authors www.springer.com/00266 .

Tri-Layered Doxycycline-, Collagen- and Bupivacaine-Loaded Poly(lactic-co-glycolic acid) Nanofibrous Scaffolds for Tendon Rupture Repair

Achilles tendon rupture is a severe injury, and its optimal therapy remains controversial. Tissue engineering scaffolds play a significant role in tendon healing and tissue regeneration. In this study, we developed tri-layered doxycycline/collagen/bupivacaine (DCB)-composite nanofibrous scaffolds to repair injured Achilles tendons. Doxycycline, collagen, and bupivacaine were integrated into poly(lactic-co-glycolic acid) (PLGA) nanofibrous membranes, layer by layer, using an electrospinning technique as healing promoters, a 3D scaffold, and painkillers, respectively. After spinning, the properties of the nanofibrous scaffolds were characterized. In vitro drug discharge behavior was also evaluated. Furthermore, the effectiveness of the DCB–PLGA-composite nanofibers in repairing ruptured Achilles tendons was investigated in an animal tendon model with histological analyses. The experimental results show that, compared to the pristine PLGA nanofibers, the biomolecule-loaded nanofibers exhibited smaller fiber size distribution and an enhanced hydrophilicity. The DCB-composite nanofibers provided a sustained release of doxycycline and bupivacaine for over 28 days in vivo. Additionally, Achilles tendons repaired using DCB-composite nanofibers exhibited a significantly higher maximum load-to-failure than normal tendons, suggesting that the biomolecule-incorporated nanofibers are promising scaffolds for repairing Achilles tendons.

Future Treatment of Neuropathic Pain in Spinal Cord Injury: The Challenges of Nanomedicine, Supplements or Opportunities?

Neuropathic pain (NP) is a common chronic condition that severely affects patients with spinal cord injuries (SCI). It impairs the overall quality of life and is considered difficult to treat. Currently, clinical management of NP is often limited to drug therapy, primarily with opioid analgesics that have limited therapeutic efficacy. The persistence and intractability of NP following SCI and the potential health risks associated with opioids necessitate improved treatment approaches. Nanomedicine has gained increasing attention in recent years for its potential to improve therapeutic efficacy while minimizing toxicity by providing sensitive and targeted treatments that overcome the limitations of conventional pain medications. The current perspective begins with a brief discussion of the pathophysiological mechanisms underlying NP and the current pain treatment for SCI. We discuss the most frequently used nanomaterials in pain diagnosis and treatment as well as recent and ongoing efforts to effectively treat pain by proactively mediating pain signals following SCI. Although nanomedicine is a rapidly growing field, its application to NP in SCI is still limited. Therefore, additional work is required to improve the current treatment of NP following SCI.

Micro- and nanocarriers for pain alleviation

Acute or chronic pain is a major source of impairment in quality of life and affects a substantial part of the population. To date, pain is alleviated by a limited range of treatments with significant toxicity, increased risk of misuse and inconsistent efficacy, owing, in part, to lack of specificity and/or unfavorable pharmacokinetic properties. Thanks to the unique properties of nanoscaled drug carriers, nanomedicine may enhance drug biodistribution and targeting, thus contributing to improved bioavailability and lower off-target toxicity. After a brief overview of the current situation and the main critical issues regarding pain alleviation, this review will examine the most advanced approaches using nanomedicine of each drug class, from the preclinical stage to approved nanomedicines.

A Novel Photoswitchable Azobenzene-Containing Local Anesthetic Ethercaine with Light-Controlled Biological Activity In Vivo

Pain is a common symptom that impairs the quality of life for people around the world. Local anesthetics widely used for pain relief have a number of side effects, which makes the development of both new drugs and new ways to control their activity particularly important. Photopharmacology makes it possible to reduce the side effects of an anesthetic and control its biological activity in the body. The purpose of this work was to create a new light-controlled local anesthetic and study its biological activity in animals. A compound with a simple scheme of synthesis was chosen to shift the UV-Vis absorption band towards the visible range of the spectrum and was synthesized for the first time. Some computer calculations were performed to make sure that the aforementioned changes would not lead to loss of biological activity. The micellar form of the new compound was prepared, and in vivo biological studies were carried out in rabbits. The existence of a local anesthetic effect, which disappeared almost completely on irradiation with light (λ = 395 nm), was shown using the surface anesthesia model. Moreover, the possibility of multiple reversible changes in the biological activity of ethercaine under the action of light was demonstrated. The latter compound manifests no local irritating effect, either. The data obtained indicate the prospects for the development of new compounds based on azobenzene for light-controlled local anesthesia.

Effects of intrathecal injection of ropivacaine on spinal cord in rats based on genomics

OBJECTIVES

There are clinical reports of nerve injury caused by ropivacaine. The mechanism for nerve injury induced by ropivacaine has not been fully clarified. This study aims to investigate the changes of pain threshold and L3 spinal cord genomics at 6 h and 24 h after intrathecal injection of 0.5% and 1.0% ropivacaine, and to explore the underlying mechanisms for nerve injury caused by ropivacaine.

METHODS

A total of 30 male Sprague Dawley rats weighing 220-260 g were successfully implanted with microspinal catheter. The rats were randomly divided into 5 groups (each n=6): a control group (given saline), a ropivacaine group 1 and a ropivacaine group 2 (both given 1% ropivacaine), a ropivacaine group 3 and a ropivacaine group 4 (both given 0.5% ropivacaine). The rats received continuous intrathecal injection of corresponding drugs at 8.3 μL/h for 24 h via an implanted intrathecal catheter followed by 24 h-pause of injection for the ropivacaine group 2, the ropivacaine group 4 and the control group, 6 h-pause of injection for the ropivacaine group 1 and the ropivacaine group 3. For each group, the observation of behavioral change and the paw withdrawal mechanical threshold (PWMT) was conducted immediately after the injection and again after the pause of injection. After the PWMT observation, the rats were dissected to acquire L3 spinal cords. Illumina sequencing was applied to construct gene libraries. Then the statistical methods were used to find out differentially expressed genes between the groups. Gene Ontology (GO) enrichment analysis and Kyoto Encyclopedia of Genes and Genomes (KEGG) signaling pathway analysis were conducted for those genes. Real-time RT-PCR was used to determine different expressions of some of those genes.

RESULTS

Compared with control group, the PWMT got higher in the ropivacaine group 1-4 and was positively correlated with concentration, negatively correlated with discontinuation duration. Compared with control group, the ropivacaine group 1 had 488 differentially expressed genes, of which 456 were up-regulated and 32 were down-regulated; the ropivacaine group 2 had 1 194 differentially expressed genes, of which 1 092 were up-regulated and 102 were down-regulated; the ropivacaine group 3 had 518 differentially expressed genes, of which 384 were up-regulated and 134 were down-regulated; and the ropivacaine group 4 had 68 differentially expressed genes, of which 46 were up-regulated and 22 were down-regulated. GO enrichment analysis and KEGG signaling pathway analysis showed that most of these differentially expressed genes were related to signaling pathways of inflammatory response.

CONCLUSIONS

After intrathecal injection of 0.5% ropivacaine and 1.0% ropivacaine for 24 h, the differentially expressed genes in L3 spinal cord of rats are mainly related to signaling pathways of inflammatory response.

Perioperative Pain Management for Elective Spine Surgery: Opioid Use and Multimodal Strategies

In recent years, physicians and institutions have come to recognize the increasing opioid epidemic in the United States, thus prompting a dramatic shift in opioid prescribing patterns. The lack of well-studied alternative treatment regimens has led to a substantial burden of opioid addiction in the United States. These forces have led to a huge economic burden on the country. The spine surgery population is particularly high risk for uncontrolled perioperative pain, because most patients experience chronic pain preoperatively and many patients continue to experience pain postoperatively. Overall, there is a large incentive to better understand comprehensive multimodal pain management regimens, particularly in the spine surgery patient population. The goal of this review is to explore trends in pain symptoms in spine surgery patients, overview the best practices in pain medications and management, and provide a concise multimodal and behavioral treatment algorithm for pain management, which has since been adopted by a high-volume tertiary academic medical center.

Local anesthetics for the Nephrologist

Several specialists in medicine use local anesthetics. In patients with kidney disease, these agents are used during catheter insertions for hemodialysis and peritoneal dialysis, arteriovenous fistula and graft procedures, kidney transplantation, parathyroidectomy, kidney biopsies, and dental and skin procedures. Patients on chronic hemodialysis use a topical application prior to use of needles for arteriovenous fistula cannulation before starting dialysis. They are also used to manage acute and chronic pain conditions, in regional nerve blockade and in multi-modal enhanced recovery protocols. Despite their frequent use by both physicians and patients, data on the use of local anesthetics in patients with kidney impairment are not well reported. This review will summarize the use of local anesthetics in chronic kidney disease, describe their pharmacology and the impact of lower estimated glomerular filtration rate on their pharmacokinetics, and suggest dose regulation in those with kidney dysfunction.

Complications After Dental Sedation: A Myotonic Mystery Case Report

Myotonic dystrophy (dystrophia myotonica; DM) is an uncommon progressive hereditary muscle disorder that can present with variable severity at birth, in early childhood, or most commonly as an adult. Patients with DM, especially type 1 (DM1), are extremely sensitive to the respiratory depressant effects of sedative-hypnotics, anxiolytics, and opioid agonists. This case report describes a 37-year-old male patient with previously undiagnosed DM1 who received dental care under minimal sedation using intravenous midazolam. During the case, the patient experienced 2 brief episodes of hypoxemia, the second of which required emergency intubation after propofol and succinylcholine and resulted in extended hospital admission. A lipid emulsion (Liposyn II 20%) infusion was given approximately 2 hours after the last local anesthetic injection due to slight ST elevation and suspicion of local anesthetic toxicity (LAST). Months after treatment, the patient suffered a fall resulting in a fatal traumatic brain injury. Complications noted in this case report were primarily attributed to the unknown diagnosis of DM1, although additional precipitating factors were likely present. This report also provides a basic review of the literature and clinical guidelines for managing myotonic dystrophy patients for dental care with local anesthesia, sedation, or general anesthesia.

Mechanisms and Efficacy of Intravenous Lipid Emulsion Treatment for Systemic Toxicity From Local Anesthetics

Local anesthetics are widely used clinically for perioperative analgesia to achieve comfort in medical treatment. However, when the concentration of local anesthetics in the blood exceeds the tolerance of the body, local anesthetic systemic toxicity (LAST) will occur. With the development and popularization of positioning technology under direct ultrasound, the risks and cases of LAST associated with direct entry of the anesthetic into the blood vessel have been reduced. Clinical occurrence of LAST usually presents as a series of severe toxic reactions such as myocardial depression, which is life-threatening. In addition to basic life support (airway management, advanced cardiac life support, etc.), intravenous lipid emulsion (ILE) has been introduced as a treatment option in recent years and has gradually become the first-line treatment for LAST. This review introduces the mechanisms of LAST and identifies the clinical symptoms displayed by the central nervous system and cardiovascular system. The paper features the multimodal mechanism of LAST reversal by ILE, describes research progress in the field, and identifies other anesthetics involved in the resuscitation process of LAST. Finally, the review presents key issues in lipid therapy. Although ILE has achieved notable success in the treatment of LAST, adverse reactions and contraindications also exist; therefore, ILE requires a high degree of attention during use. More in-depth research on the treatment mechanism of ILE, the resuscitation dosage and method of ILE, and the combined use with other resuscitation measures is needed to improve the efficacy and safety of clinical resuscitation after LAST in the future.

Local anesthetic systemic toxicity in the pediatric patient: A case report and review of the literature

Lidocaine and prilocaine are local anesthetics, a class of medications which are frequently used in clinical medicine to minimize pain in a variety of procedures. They are commonly found in over-the-counter products such as topical anesthetic creams advertised to relieve localized muscle and joint pain. While safe and well-tolerated when used appropriately, an overdose of these anesthetics increases the risk for local anesthetic systemic toxicity (LAST), which in severe cases can present with seizures, cardiac dysrhythmias, and ultimately cardiovascular collapse. The reduced muscle mass of pediatric patients puts them at an increased risk of LAST due to the depot effect of the systemically absorbed anesthetic. Methemoglobinemia may also be associated with local anesthetic toxicity. Our case involves a previously healthy 15-month-old female who presented to one of our networks' emergency departments in status epilepticus following an accidental ingestion of a tube of 2.5% lidocaine/2.5% prilocaine cream. Her seizure activity was initially resistant to intraosseous benzodiazepine administration, but ultimately resolved following administration of lipid emulsion and sodium bicarbonate. Additionally, the patient had refractory hypoxia on the monitor which resolved shortly after administration of methylene blue. After stabilization, the patient was transferred to the Pediatric ICU and ultimately made a complete recovery. LAST is a life-threatening presentation which requires early recognition by clinicians, as well as an understanding of the appropriate treatment modalities. We review the assessment and management of LAST, with special focus on the pediatric patient.

Biodegradable Antimicrobial Agent/Analgesic/Bone Morphogenetic Protein-Loaded Nanofibrous Fixators for Bone Fracture Repair

Purpose

Postoperative infection and pain management are of great concern to orthopedic surgeons. Although there are several protocols available to deal with these aspects, they are fraught with complications, such as cartilage damage, cardiovascular and neurological intoxication, and systemic adverse responses. Therefore, it is necessary to develop safe and effective perioperative protocols. In the current study, antimicrobial agents/analgesics/growth factor-embedded biodegradable hybrid fixators (polycaprolactone fixator + poly[lactide-co-glycolide] sheath-core structured nanofibers) for bone fracture repair were designed.

Methods

The biodegradable hybrid fixators were fabricated using solution-extrusion three-dimensional printing and electrospinning. In vitro, the characteristics of the hybrid fixators were examined. Additionally, the release of the incorporated vancomycin, ceftazidime, lidocaine, and bone morphogenetic protein-2 (BMP-2) was evaluated. The in vivo efficacy including drug-eluting properties, fracture repair, and pain management of the biomolecule-loaded nanofibrous fixators was investigated in rabbit rib-fracture models.

Results

The nanofibrous fixators released vancomycin, ceftazidime, and lidocaine in a sustained manner under both in vitro and in vivo conditions and protected BMP-2 from burst release. The implantation of these hybrid fixators around the fractured rib significantly improved animal activities and bone union, indicating that the inclusion of analgesic in the fixator effectively reduced postsurgical pain and thereby helped in recovery.

Conclusion

The novel biomolecule-loaded nanofibrous hybrid fixators resulted in excellent therapeutic outcomes. These fixators may be effective in the repair of rib fractures in clinical settings and may help mitigate surgical complications, such as infection, nonunion, and intolerable postoperative pain.

Nanotechnology for Pain Management: Current and Future Therapeutic Interventions

Pain is one of the most common medical conditions and affects more Americans than diabetes, heart disease, and cancer combined. Current pain treatments mainly rely on opioid analgesics and remain unsatisfactory. The life-threatening side effects and addictive properties of opioids demand new therapeutic approaches. Nanomedicine may be able to address these challenges as it allows for sensitive and targeted treatments without some of the burdens associated with current clinical pain therapies. This review discusses the physiology of pain, the current landscape of pain treatment, novel targets for pain treatment, and recent and ongoing efforts to effectively treat pain using nanotechnology-based approaches. We highl ight advances in nanoparticle-based drug delivery to reduce side effects, gene therapy to tackle the source of pain, and nanomaterials-based scavenging to proactively mediate pain signaling.

Lidocaine: A Local Anesthetic, Its Adverse Effects and Management

The most widely used medications in dentistry are local anesthetics (LA), especially lidocaine, and the number of recorded adverse allergic responses, particularly of hazardous responses, is quite low. However, allergic reactions can range from moderate to life-threatening, requiring rapid diagnosis and treatment. This article serves as a review to provide information on LA, their adverse reactions, causes, and management.

Dexmedetomidine may decrease the bupivacaine toxicity to heart

Objective

The purpose of our study was to explore the effect of dexmedetomidine on cardiac tolerance to bupivacaine.

Method

Human coronary endothelial cells were used to establish in vitro model. They were randomly divided into control (Con) group, dexmedetomidine (Dex) group, bupivacaine (Bupi) group, dexmedetomidine + bupivacaine group (DB group), and dexmedetomidine + bupivacaine + PI3K inhibitor (DB-inhibitor) group. Cell activity was measured by Cell counting kit-8 (CCK-8). Transwell was used to detect cell permeability. Western blotting was used to detect the protein expression of related factors.

Results

There were no notable differences in cell activity among the five groups (P > 0.05). Dexmedetomidine significantly reduced the permeability of endothelial cells to bupivacaine and increased the protein expression of Zonulaoeeludens-1 (ZO-1) (P < 0.01). However, the aforementioned effects of dexmedetomidine were disappeared after the addition of PI3K inhibitors. Furthermore, Dex and DB markedly increased the protein expression of PI3K, p-Akt, and p-PTEN in comparison with Con group (P < 0.001), but there was no significant difference in p-PTEN among DB-inhibitor, Con, and Bupi groups (P > 0.05).

Conclusion

Dex reduced Bupi-induced vasopermeability through protein expression of ZO-1 and PI3K/Akt pathway, which may lead to the decrease of Bupi-induced cardiotoxicity.

Postoperative pain treatment with transmuscular quadratus lumborum block and fascia iliaca compartment block in patients undergoing total hip arthroplasty: a randomized controlled trial

Background

Patients often suffer moderate or even severe pain after total hip arthroplasty; such pain seriously affects early postoperative recovery. This study aimed to investigate the analgesic efficacy of ultrasound-guided transmuscular quadratus lumborum block combined with fascia iliaca compartment block for elderly patients undergoing total hip arthroplasty.

Methods

Fifty-four patients scheduled for total hip arthroplasty were included in this randomized controlled study. The patients were randomly assigned to receive only transmuscular quadratus lumborum block (group Q) or transmuscular quadratus lumborum block combined with fascia iliaca compartment block (group QF) with ultrasound guidance. Postoperatively in both groups, paracetamol 1 g was regularly administered at 6 h intervals and patient-controlled intravenous analgesia was administered. The primary outcome was cumulative sufentanil consumption via patient-controlled intravenous analgesia 24 h postoperatively. The secondary outcomes included pain degree, time to the first analgesic requirement, joint range of motion, quality of recovery, and the incidence of postoperative complications.

Results

Fifty patients were included, and their data were analyzed. The cumulative sufentanil consumption in group QF was significantly lower during the first 24 h after surgery than that in group Q, and the cumulative sufentanil consumption in group QF was reduced at 6–12 and 12–18 h after surgery. The postoperative pain intensity was lower in group QF than in group Q (linear mixed-effects model, the main effect of treatment: P < 0.001). Compared with group Q, group QF had higher quality of recovery and joint range of movement. The time to the first analgesic requirement was longer in group QF than in group Q (log-rank, P < 0.001). There was no statistically significant difference in complications postoperatively between the two groups.

Conclusions

Our study provides a multimodal, opioid-sparing analgesic regimen for elderly patients undergoing total hip arthroplasty. The combination of transmuscular quadratus lumborum block and fascia iliaca compartment block provides a significant advantage for early postoperative functional recovery. Further studies are required to confirm the minimum effective dose.

Trial registration

The study was registered on the 21st December 2020 (retrospectively registered) on the Chinese Clinical Trial Registry: ChiCTR2000038686.

Lidocaine Infusions for Pain Management in Pediatrics

Lidocaine is an amino amide with a well-established role as a local anesthetic agent. Systemic intravenous administration expands its clinical use to include acute and chronic pain circumstances, such as postoperative pain, neuropathic pain, postherpetic neuralgia, hyperalgesia, visceral pain, and centrally mediated pain. For refractory pain that has not responded to conventional therapy or if further escalation of treatment is prevented by contraindications or side effects to standard therapies, a continuous infusion of lidocaine may be considered as a single intervention or as a sequence of infusions. Here, we review and evaluate published data reflecting the use of lidocaine continuous infusions for pain management in the pediatric population.

P53 inhibitor pifithrin-α inhibits ropivacaine-induced neuronal apoptosis via the mitochondrial apoptosis pathway

The neurotoxicity of local anesthetics (LAs) has attracted more and more attention, However, they lack preventive and therapeutic measures. Many studies have shown that apoptosis plays an important role in the process of LA-induced neurotoxicity. As an important signaling molecule to activate apoptosis, p53 has been proved to be involved in the neurotoxicity induced by LAs, but the mechanism is unclear. In this study, we explored the effect of pifithrin-α (PFT-α), a p53 inhibitor, on apoptosis by ropivacaine (Rop) in vivo and in vitro. Cell viability and apoptosis detected by CCK-8 and a JC-1 apoptosis detection kit, the changes of spinal cord structure observed after hematoxylin and eosin staining, apoptosis of the spinal cord measured by terminal deoxynucleotidyl transferase dUTP nick end labeling staining, behavioral assessment of the nerve Injury evaluated by the detection of sciatic nerve conduction velocity (SNCV) andmechanical withdrawal threshold (MWT), the expression of p53 and many apoptosis-related genes included Bax, Bcl-2, and caspase-3 detected by quantitative real-time polymerase chain reaction, Western blot analysis, immunofluorescence, and immunohistochemistry. Results showed that PC12 cell viability decreased because of Rop, but the pretreatment of PFT-α could protect it. And PFT-α reduced the injuries in the spinal cord by Rop included vacuoles or edema. The results of immunofluorescence and immunohistochemistry testing showed that PFT-α inhibited the p53 protein upregulated by Rop. Apoptosis rate and many proapoptotic genes include p53, Bax, caspase-3 messenger RNA, and proteins were increased by Rop, but PFT-α could decrease it. In conclusion, PFT-α inhibited cell apoptosis and spinal cord injuries induced by Rop.

Two fatal and four surviving cases after accidental infusion of ropivacaine

Purpose

In this paper, we describe six cases, where patients were falsely treated with pre-filled ropivacaine solution instead of medical saline solution for postoperative settings. Two of the patients died because of fatal concentrations of ropivacaine in blood, four survived with no further physical injury, and two of them showed typical intoxication symptoms. The collected blood and urine samples of the deceased, as well as the surviving patients, were analyzed in laboratory routine screening.

Methods

Ropivacaine and its main metabolite 3-OH-ropivacaine were analyzed by gas chromatography–mass spectrometry.

Results

All of the six cases showed positive blood results of ropivacaine. Due to the poorly secured sample material of the survived patients at hospital, the quantitative examination of 3-OH-ropivacaine could not be carried out. In one fatal case, there were ropivacaine and 3-OH-ropivacaine traceable in urine. In all cases, metamizole was found in blood and traces of piritramide in urine. The amount of metamizole was within the upper limits of therapeutical treatment values. Patients with lower blood concentrations of ropivacaine showed more physical symptoms as compared to those with higher concentrations of active substances.

Conclusions

In the context of symptom development and intoxication, the speed of injection was a very important factor to cause fatal ropivacaine cases. To our knowledge, these are the first reported cases of fatal intoxication with ropivacaine.

Complications of Intraosseous Access: Two Case Reports From a Single Center

CASES

Intraosseous (IO) access is an effective surrogate for intravascular access in critically ill patients. We present 2 cases of IO complications. The first patient is a 44-year-old man with deep peroneal nerve sensorimotor dysfunction due to possible missed acute compartment syndrome from improper placement of a tibial IO needle. The second patient is an immunosuppressed 69-year-old man with idiopathic factor VIII deficiency who required amputation 7 months after right tibia IO access.

CONCLUSION

These adverse events of IO access are limited in the literature. We make recommendations to reduce these outcomes.

In vitro evaluation of loaded chitosan membranes for pain relief and infection prevention

Wounds resulting from surgeries, implantation of medical devices, and musculoskeletal trauma result in pain and can also result in infection of damaged tissue. Up to 80% of these infections are due to biofilm formation either on the surface of implanted devices or on surrounding wounded tissue. Bacteria within a biofilm have intrinsic growth and development characteristics that allow them to withstand up to 1,000 times the minimum inhibitory concentration of antibiotics, demonstrating the need for new therapeutics to prevent and treat these infections. Cis-2-decenoic acid (C2DA) is known to disperse preformed biofilms and can prevent biofilm formation entirely for some strains of bacteria. Additionally, local anesthetics like bupivacaine have been shown to have antimicrobial effects against multiple bacterial strains. This study sought to evaluate hexanoic acid-treated electrospun chitosan membranes (HA-ESCM) as wound dressings that release C2DA and bupivacaine to simultaneously prevent infection and alleviate pain associated with musculoskeletal trauma. Release profiles of both therapeutics were evaluated, and membranes were tested in vitro against Methicillin-resistant Staphylococcus aureus (MRSA) to determine efficacy in preventing biofilm infection and bacterial growth. Results indicate that membranes release both therapeutics for 72 hr, and release profile can be tailored by loading concentration. Membranes were effective in preventing biofilm growth but were toxic to fibroblasts when loaded with 2.5 or 5 mg of bupivacaine.

Minimally Invasive Triple Therapy of the Presurgical Neck

Minimally invasive in-office procedures are a fast growing field in plastic surgery. Patients often notice and complain about their neck at an earlier age. Modern treatments for the aging neck have continued to evolve over the past decade, with more options continuing to become available. In this article, we describe our noninvasive approach to the aging neck through the combination of submental liposuction, radiofrequency (RF) microneedling, and percutaneous RF as a safe and effective option. Through appropriate patient selection, preoperative counseling, and good surgical technique, appropriate results can be achieved with minimal downtime. Patient selection, counseling, appropriate anesthesia, procedure details, and results are discussed in this article.

Electrocorticographic description of the effects of anticonvulsant drugs used to treat lidocaine-induced seizures

INTRODUCTION

Local anesthetics are widely used in clinical practice. While toxicity is rare, these drugs can cause potentially lethal seizures.

OBJECTIVE

In the present study, we investigated the electrocorticographic (ECoG) and electromyographic patterns of seizures induced by acute lidocaine (LA) toxicity and treated with anticonvulsant drugs. The study used adult male Wistar rats to describe of the seizure-related behavior of LA and investigated the treatment with anticonvulsant drugs.

RESULTS

The use of LA resulted in clear changes in the ECoG pattern, which presented characteristics of Status epilepticus, with increased intensity in all brainwaves. The decomposition of the cerebral waves showed an increase in the beta and gamma waves that may be related to tonic-clonic seizure. Although the treatment with anticonvulsants drugs reduces the power of brainwaves at frequencies between 1 and 40 Hz compared to the LA group, but only diazepam (DZP) was able to decrease the intensity of oscillations. The muscle contraction power also indicated a difference in the effectiveness of the three treatments.

CONCLUSION

The sum of the evidence indicates that LA causes status epilepticus and that DZP is the most effective treatment for the control of these seizures, by restoring the systemic values to levels close to those recorded in the control group.

Care and management of patients receiving epidural analgesia

Epidural analgesia continues to have an important role in the management of acute pain in post-operative settings. Although its use in clinical practice has declined, it continues to demonstrate superior analgesia effect compared with parenteral opioids. However, despite these benefits, epidural analgesia requires additional monitoring to ensure the timely identification of significant complications, such as haematoma and abscess. This article details the nursing care and management of adults receiving epidural analgesia in post-operative settings. It also outlines the main complications that may occur and how these can be managed.

Local anaesthesia in dentistry: a review

Over the past century, there is perhaps no greater contribution to the practice of clinical dentistry than the development and application of local anaesthesia. What were once considered painful procedures have now been made routine by the deposition and action of local anaesthetics. This article will serve as a review of basic pharmacological principles of local anaesthesia, subsequent sequelae that can arise from their use, considerations when using local anaesthetics, and recent advances in the delivery of local anaesthetics.

Regional Anesthesia: An Overview

Advances in anesthesia techniques and guidance imaging have made regional anesthetics effective both for pain management and as a primary anesthesia modality for patients undergoing operative and other invasive procedures. Patients can receive regional anesthesia in most areas of the body, including the upper and lower extremities and torso. It is critical that perioperative nurses are familiar with regional anesthetic options and understand them well enough to support their patients in the preoperative, intraoperative, and postoperative phases of surgical care. They also should be familiar with the signs and symptoms of local anesthetic systemic toxicity and be prepared to help treat this condition as soon as indicated. Nurses play a pivotal role in ensuring patients are properly educated about regional anesthetics and remain safe throughout all phases of perioperative care.

Injectable PLGA-Coated Ropivacaine Produces A Long-Lasting Analgesic Effect on Incisional Pain and Neuropathic Pain

The management of persistent postsurgical pain and neuropathic pain remains a challenge in the clinic. Local anesthetics have been widely used as simple and effective treatment for these 2 disorders, but the duration of their analgesic effect is short. We here reported a new poly lactic-co-glycolic acid (PLGA)-coated ropivacaine that was continuously released in vitro for at least 6 days. Perisciatic nerve injection of the PLGA-coated ropivacaine attenuated paw incision-induced mechanical allodynia and heat hyperalgesia during the incisional pain period, and spared nerve injury-induced mechanical and cold allodynia for at least 7 days postinjection. This effect was dose-dependent. Perisciatic nerve injection of the PLGA-coated ropivacaine did not produce detectable inflammation, tissue irritation, or damage in the sciatic nerve and surrounding muscles at the injected site, dorsal root ganglion, spinal cord, or brain cortex, although the scores for grasping reflex were mildly and transiently reduced in the higher dosage-treated groups. PERSPECTIVE: Given that PLGA is an FDA-approved medical material, and that ropivacaine is used currently in clinical practice, the injectable PLGA-coated ropivacaine represents a new and highly promising avenue in the management of postsurgical pain and neuropathic pain.

Local infiltration of tramadol as an effective strategy to reduce post-operative pain: a systematic review protocol and meta-analysis

OBJECTIVE

The purpose of this review is to evaluate the use and effectiveness of the local administration of tramadol in reducing post-operative pain during surgical interventions.

METHODS

The PubMed, EMBASE and Cochrane Central Register of Controlled Trials (CENTRAL) databases will be searched for this review. This systematic review will include studies evaluating the clinical efficacy of the local infiltration of tramadol, with no study design restrictions. Only studies that present clear descriptions of local tramadol administration are published in peer-reviewed journals in the English, Italian, Spanish, French, Portuguese or German language and are published in full will be taken into consideration. A meta-analysis will be performed when there is sufficient clinical homogeneity among the retrieved studies, and only randomized controlled studies and quasi-randomized controlled studies will be included. The Grading of Recommendations Assessment, Development and Evaluation (GRADE) approach will be used to assess the certainty in the evidence. If a quantitative analysis cannot be conducted, a qualitative description of the results of the retrieved studies will be provided.

RESULTS

A high-quality synthesis of the current evidence on the local administration of tramadol for managing post-surgical pain will be illustrated using subjective reports and objective measures of performance. The primary outcomes will include the magnitude of post-operative pain intensity improvement, with improvement being as defined by a reduction by at least 2 points in the visual analogue scale (VAS) score or numerical rating scale (NRS) score. The secondary outcomes will be the magnitude of reduction in tramadol rescue doses and in other analgesic drug doses.

CONCLUSION

This protocol will present evidence on the efficacy of tramadol in relieving post-surgical pain.

SYSTEMIC REVIEW REGISTRATION

PROSPERO CRD42018087381.

Local Anesthetic Facelift

A thorough medical history is critical in patient selection for local anesthesia facelifting. Patients with no prior issues with dental procedures and no history of significant anxiety are better candidates. Simplifying local anesthesia mixtures and using dilute concentrations will minimize dosing errors and decrease risk of local anesthesia toxicity. Oral anxiolytics can be used with caution to minimize patient anxiety. Pulse oximetry, telemetry, and blood pressure monitoring should be performed with any addition of oral or IV sedation/anxiolytic. The short-scar anterior facelift is ideal for local anesthesia due to the limited deep-plane dissection and shorter procedure duration.

Dexmedetomidine protects against lidocaine-induced neurotoxicity through SIRT1 downregulation-mediated activation of FOXO3a

Lidocaine, a typical local anesthetic, has been shown to directly induce neurotoxicity in clinical settings. Dexmedetomidine (DEX) is an alpha-2-adrenoreceptor agonist that has been used as anxiolytic, sedative, and analgesic agent which has recently found to protect against lidocaine-induced neurotoxicity. Nicotinamide adenine dinucleotide-dependent deacetylase sirtuin-1 (SIRT1)/forkhead box O3 (FOXO3a) signaling is critical for maintaining neuronal function and regulation of the apoptotic pathway. In the present study, we designed in vitro and in vivo models to investigate the potential effects of lidocaine and DEX on SIRT1 and FOXO3a and to verify whether SIRT1/FOXO3a-mediated regulation of apoptosis is involved in DEX-induced neuroprotective effects against lidocaine. We found that in both PC12 cells and brains of mice, lidocaine decreased SIRT1 level through promoting the degradation of SIRT1 protein. Lidocaine also increased FOXO3a protein level and increased the acetylation of SIRT1 through inhibiting SIRT1. Upregulation of SIRT1 or downregulation of FOXO3a significantly inhibited lidocaine-induced changes in both cell viability and apoptosis. DEX significantly inhibited the lidocaine-induced decrease of SIRT1 protein level and increase of FOXO3a protein level and acetylation of FOXO3a. Downregulation of SIRT1 or upregulation of FOXO3a suppressed DEX-induced neuroprotective effects against lidocaine. The data suggest that SIRT1/FOXO3a is a potential novel target for alleviating lidocaine-induced neurotoxicity and provide more theoretical support for the use of DEX as an effective adjunct to alleviate chronic neurotoxicity induced by lidocaine.

The effect of retrobulbar anesthesia for cataract surgery on the retinal nerve fiber layer thickness

OBJECTIVE

The aim of this study was to evaluate the effect retrobulbar and topical anesthesia on optic nerve by measuring retinal nerve fiber layer (RNFL) thickness before and after phacoemulsification cataract surgery using optical coherence tomography (OCT).

METHODS

A total of 126 eyes of 108 patients were included in the study. Retrobulbar anesthesia was used in 61 eyes of 53 patients, and topical anesthesia was used in 65 eyes of 55 patients. OCT scans were done 1 week before the surgery and 4 weeks after surgery, and the results were evaluated.

RESULTS

The average RNFL thickness increased postoperatively in both groups (p < 0.001 for topical anesthesia group and p = 0.001 for retrobulbar anesthesia group). The preoperative and postoperative average and quadrant RNFL thickness and the change in RNFL thickness were not significantly different between the two anesthesia groups (p > 0.05).

CONCLUSION

Our results suggest that retrobulbar anesthesia has no unfavorable effect on the retinal nerve fiber layer.