The in vitro mechanisms and in vivo efficacy of intravenous lidocaine on the neuroinflammatory response in acute and chronic pain

Effects of intravenous lidocaine on postoperative pain and gastrointestinal function recovery following gastrointestinal surgery: a meta-analysis

INTRODUCTION

The full extent of intravenous lidocaine's effectiveness in alleviating postoperative pain and enhancing gastrointestinal function recovery remains uncertain.

EVIDENCE ACQUISITION

We conducted an exhaustive search of databases to identify randomized controlled trials that compared intravenous lidocaine infusion's efficacy to that of a placebo or routine care in patients undergoing gastrointestinal surgery. The primary outcome measure was resting pain scores 24 h postoperatively. We utilized a random-effects model based on the intention-to-treat principle for the overall results.

EVIDENCE SYNTHESIS

This study included twenty-four trials with 1533 patients. Intravenous lidocaine significantly reduced resting pain scores 24 h after gastrointestinal surgery (twenty trials, SMD -0.67, 95% CI -1.09 to -0.24, P=0.002, I2 = 90%). This finding was consistent in subgroup analyses and sensitivity analyses. The benefit was also observed at other resting and moving time points (1, 2, 4, and 12 h) postoperatively. Intravenous lidocaine significantly decreased opioid consumption within 24 h after surgery (eleven trials, SMD: -1.19; 95% CI: -1.99 to -0.39; P=0.003). Intravenous lidocaine also shortened the time to bowel sound (MD: -8.51; 95% CI: -14.59 to -2.44; P=0.006), time to first flatus (MD: -6.00; 95% CI: -9.87 to -2.13; P=0.002), and time to first defecation (MD: -9.77; 95% CI: -17.19 to -2.36; P=0.01).

CONCLUSIONS

Perioperative intravenous lidocaine can alleviate acute pain and expedite gastrointestinal function recovery in patients undergoing gastrointestinal surgery. However, the results should be interpreted with caution due to substantial heterogeneity. Further large-scale studies are necessary to validate these findings.

Patient Expectations and Therapeutic Alliance Affect Pain Reduction Following Lidocaine Infusion in an Interdisciplinary Chronic Pain Clinic

Pain experience is affected by both ascending nociceptive signals and descending modulation. Expectations can affect pain experience and augment treatment-induced analgesia through descending inhibitory modulation of pain. This open-label, prospective cohort study examined the association between participant expectation ratings and pain reduction in adult participants with chronic pain receiving an intravenous lidocaine infusion. We aimed to explore whether: 1) participants' expectations of treatment efficacy were associated with pain reduction over 8 weeks after infusion; and 2) participants' therapeutic alliance was associated with expectations and/or pain reduction. We recruited 70 participants with chronic pain scheduled for lidocaine infusion. Study measures included pain intensity (pre-treatment, post-treatment, and daily for 8 weeks), treatment expectations (EXPECT), and therapeutic alliance (Trust in Physician and Working Alliance Inventory-Short Revised). Baseline treatment expectations were significantly correlated with pain reduction (r = .42, P < .01). Therapeutic alliance was significantly correlated with expectations (r = .27, P < .05) and pain reduction (r = .38, P < .01). This study quantifies the contribution of: 1) treatment expectations; and 2) therapeutic alliance to the magnitude of lidocaine-induced pain reduction. Results generate the hypothesis that focused efforts to augment treatment expectations and therapeutic alliance could serve to improve pain treatment outcomes. PERSPECTIVE: This study evaluates the relationship between pain reduction and ratings of: 1) treatment expectations; and 2) therapeutic alliance following an intravenous lidocaine infusion. Results generate the hypothesis that focused efforts to augment treatment expectations and therapeutic alliance could serve to improve pain treatment outcomes.

Intranasal Lidocaine Administration via Mucosal Atomization Device: A Simple and Successful Treatment for Postdural Puncture Headache in Obstetric Patients

(1) Background: Postdural puncture headache (PDPH) remains a serious complication in obstetric patients. While the epidural blood patch represents the current gold standard in therapy, a growing number of alternative measures are thought to be beneficial for clinical management. The purpose of this study was to retrospectively analyze the efficacy of intranasal lidocaine administration to treat PDPH in obstetrics at our university hospital; (2) Methods: A retrospective analysis of the medical records of patients with PDPH has been performed focusing on the techniques of administration, dosing, treatment duration, impact on pain intensity as well as side effects of intranasal lidocaine; (3) Results: During the study period, 5610 obstetric patients received neuraxial anesthesia, of whom 43 (0.77%) developed PDPH. About one third of the patients with PDPH after spinal anesthesia (n = 8), epidural anesthesia (n = 5) or both (n = 2) were treated with intranasal lidocaine. Lidocaine was administered either via gauze compresses (GC, n = 4), a mucosal atomization device (MAD, n = 8) or with a second-line mucosal atomization device due to low gauze compress efficacy (n = 3). All patients treated with lidocaine refused the epidural blood patch. Nebulization of lidocaine resulted in a significant reduction in pain intensity after the first dose (p = 0.008). No relevant side effects developed except sporadic temporal pharyngeal numbness. The utilization of the mucosal atomization device averted the necessity for an epidural blood patch, whether employed as the primary or secondary approach; (4) Conclusions: Our data imply that the mucosal atomization device enhances the efficacy of intranasal lidocaine administration in obstetric patients suffering from PDPH.

Ketamine Infusions for Treatment-Resistant Neuropathic Pruritus

This case report describes a patient in her 50s with a 4-year history of brachioradial pruritus with bilateral pruritus on her upper arms and forearms.

Systemic Anti-Inflammatory Effects of Intravenous Lidocaine in Surgical Patients: A Systematic Review and Meta-Analysis

There has recently been increasing evidence that the use of perioperative intravenous lidocaine infusion possesses analgesic, opioid-sparing and anti-inflammatory effects in surgical patients. Although opioid-sparing and analgesic properties have been strongly supported, the anti-inflammatory features are not well established in elective surgery. Therefore, the aim of this systematic review is to examine the effect of perioperative intravenous lidocaine infusion on postoperative anti-inflammatory status in patients undergoing elective surgery. A search strategy was created to identify suitable randomised clinical trials (RCTs) in PubMed, Scopus, Web of Science and Clinicaltrials.gov databases until January 2023. RCTs that evaluated the effect of intravenous lidocaine infusion, compared with placebo, on adult patients who underwent elective surgery, in inflammatory markers response were included. Exclusion criteria consisted of paediatric patients, animal studies, non-RCT methodology, intervention without intravenous lidocaine, inadequate control group, duplicated samples, ongoing studies and lack of any relevant clinical outcome measures. The following inflammatory markers-interleukin (IL)-6, tumour necrosis factor (TNF)-α, IL-1RA, IL-8, IL-10, C-reactive protein (CRP), IL-1, IL-1β, interferon (IFN)-γ, cortisol, IL-4, IL-17, high-mobility group protein B1 (HMGB1) and transforming growth factor (TGF)-β-were evaluated as outcomes in this review. A total of 21 studies, including 1254 patients, were identified. Intravenous lidocaine infusion significantly reduced the change from IL-6 baseline levels at the end of surgery compared to a placebo (standardised mean difference [SMD]: -0.647, 95% confidence interval [CI]: -1.034 to -0.260). Usage of lidocaine was associated with a significant reduction in other postoperative pro-inflammatory markers, such as TNF-α, IL-1RA, IL-8, IL-17, HMGB-1 and CRP. There was no significant difference in other markers, such as IL-10, IL-1β, IL-1, IFN-γ, IL-4, TGF-β and cortisol. This systematic review and meta-analysis provide support for the administration of perioperative intravenous lidocaine infusion as an anti-inflammatory strategy in elective surgery.

Lidocaine inhibits influenza a virus replication by up-regulating IFNα4 via TBK1-IRF7 and JNK-AP1 signaling pathways

Influenza A viruses (IAV), significant respiratory pathogenic agents, cause seasonal epidemics and global pandemics in intra- and interannual cycles. Despite effective therapies targeting viral proteins, the continuous generation of drug-resistant IAV strains is challenging. Therefore, exploring novel host-specific antiviral treatment strategies is urgently needed. Here, we found that lidocaine, widely used for local anesthesia and sedation, significantly inhibited H1N1(PR8) replication in macrophages. Interestingly, its antiviral effect did not depend on the inhibition of voltage-gated sodium channels (VGSC), the main target of lidocaine for anesthesia. Lidocaine significantly upregulated early IFN-I, interferon α4 (IFNα4) mRNA, and protein levels, but not those of early IFNβ in mouse RAW 264.7 cell line and human THP-1 derived macrophages. Knocking out IFNα4 by CRISPR-Cas9 partly reversed lidocaine's inhibition of PR8 replication in macrophages. Mechanistically, lidocaine upregulated IFNα4 by activating TANK-binding kinase 1 (TBK1)-IRF7 and JNK-AP1 signaling pathways. These findings indicate that lidocaine has an incredible antiviral potential by enhancing IFN-I signaling in macrophages. In conclusion, our results indicate the potential auxiliary role of lidocaine for anti-influenza A virus therapy and even for anti-SARS-CoV-2 virus therapy, especially in the absence of a specific medicine.

Integrating mechanistic-based and classification-based concepts into perioperative pain management: an educational guide for acute pain physicians

Chronic pain begins with acute pain. Physicians tend to classify pain by duration (acute vs chronic) and mechanism (nociceptive, neuropathic and nociplastic). Although this taxonomy may facilitate diagnosis and documentation, such categories are to some degree arbitrary constructs, with significant overlap in terms of mechanisms and treatments. In clinical practice, there are myriad different definitions for chronic pain and a substantial portion of chronic pain involves mixed phenotypes. Classification of pain based on acuity and mechanisms informs management at all levels and constitutes a critical part of guidelines and treatment for chronic pain care. Yet specialty care is often siloed, with advances in understanding lagging years behind in some areas in which these developments should be at the forefront of clinical practice. For example, in perioperative pain management, enhanced recovery protocols are not standardized and tend to drive treatment without consideration of mechanisms, which in many cases may be incongruent with personalized medicine and mechanism-based treatment. In this educational document, we discuss mechanisms and classification of pain as it pertains to commonly performed surgical procedures. Our goal is to provide a clinical reference for the acute pain physician to facilitate pain management decision-making (both diagnosis and therapy) in the perioperative period.

Treatment of Pain in Rabbits

Rabbits occupy facets of veterinary medicine spanning from companion mammals, wildlife medicine, zoologic species, and research models. Therefore, analgesia is required for a variety of conditions in rabbits and is a critical component of patient care. Considerations when selecting an analgesic protocol in rabbits include timing of administration, route of administration, degree or anticipated pain, ability to access or use controlled drugs, systemic health, and any potential side effects. This review focuses on pharmacologic and locoregional management of pain in rabbits and emphasizes the need for further studies on pain management in this species.

One-step fabrication of lidocaine/CalliSpheres® composites for painless transcatheter arterial embolization

BACKGROUND

Transcatheter arterial embolization (TAE) is one of the first-line treatments for advanced hepatocellular cancer. The pain caused by TAE is a stark complication, which remains to be prevented by biomedical engineering methods.

METHODS

Herein, a commercial embolic agent CalliSpheres^® bead (CB) was functionally modified with lidocaine (Lid) using an electrostatic self-assembly technique. The products were coded as CB/Lid-n (n = 0, 5, 10, corresponding to the relative content of Lid). The chemical compositions, morphology, drug-loading, and drug-releasing ability of CB/Lid-n were comprehensively investigated. The biocompatibility was determined by hemolysis assay, live/dead cell staining assay, CCK8 assay, immunofluorescence (IHC) staining assay and quantitative real-time PCR. The thermal withdrawal latency (TWL) and edema ratio (ER) were performed to evaluate the analgesia of CB/Lid-n using a plantar inflammation model. A series of histological staining, including immunohistochemistry (IL-6, IL-10, TGF-β and Navi1.7) and TUNEL were conducted to reveal the underlying mechanism of anti-tumor effect of CB/Lid-n on a VX2-tumor bearing model.

RESULTS

Lid was successfully loaded onto the surface of CalliSpheres^® bead, and the average diameter of CalliSpheres^® bead increased along with the dosage of Lid. CB/Lid-n exhibited desirable drug-loading ratio, drug-embedding ratio, and sustained drug-release capability. CB/Lid-n had mild toxicity towards L929 cells, while triggered no obvious hemolysis. Furthermore, CB/Lid-n could improve the carrageenan-induced inflammation response micro-environment in vivo and in vitro. We found that CB/Lid-10 could selectively kill tumor by blocking blood supply, inhibiting cell proliferation, and promoting cell apoptosis. CB/Lid-10 could also release Lid to relieve post-operative pain, mainly by remodeling the harsh inflammation micro-environment (IME).

CONCLUSIONS

In summary, CB/Lid-10 has relatively good biocompatibility and bioactivity, and it can serve as a promising candidate for painless transcatheter arterial embolization.

Efficacy of Acupuncture, Intravenous Lidocaine, and Diet in the Management of Patients with Fibromyalgia: A Systematic Review and Network Meta-Analysis

Introduction: This network meta-analysis aimed to assess the efficacy of acupuncture, intravenous lidocaine, and diet compared with other comparators such as physiotherapy and sham/placebo in fibromyalgia patients. Materials and Methods: We searched Embase, PubMed, Scopus, and Web of Science for relevant studies till September 2021. The included studies were randomized controlled clinical trials. For the network meta-analysis, we used the R software. Results: There were 23 included RCTs. The total sample size was 1409 patients. Compared with the sham/placebo group, the network analysis showed the highest improvement in the quality of life in the acupuncture group standardized mean difference (SMD) = −10.28, 95%-CI [−14.96; −5.59]), and then in the physiotherapy group (SMD = −7.48, 95%-CI [−14.72; −0.23]). For the pain, there was a significant reduction with acupuncture (SMD = −1.69, 95%-CI [−2.48; −0.89]), compared with sham/placebo. Regarding depression, it showed a significant reduction with acupuncture (SMD = −9.64, 95%-CI [−16.13; −3.14]) compared with sham/placebo. Finally, for stiffness, it showed no significant differences in the stiffness between acupuncture (SMD = −8.52, 95%-CI [−20.40; 3.36]), fluoxetine (SMD = −6.52, 95%-CI [−29.65; 16.61]), and physiotherapy (SMD = −4.64, 95%-CI [−22.83; 13.54]) compared with sham/placebo. Conclusions: The acupuncture showed a significant effect in the management of fibromyalgia patients. It reduced pain, depression, and enhanced the quality of life. While physiotherapy showed a significant improvement in the quality of life only. In contrast, intravenous lidocaine and diet showed no significant differences when compared with sham/placebo.

Management of Postoperative Pain in Patients Following Spine Surgery: A Narrative Review

Perioperative pain management is a unique challenge in patients undergoing spine surgery due to the increased incidence of both pre-existing chronic pain conditions and chronic postsurgical pain. Peri-operative planning and counseling in spine surgery should involve an interdisciplinary approach that includes consideration of patient-level risk factors, as well as pharmacologic and non-pharmacologic pain management techniques. Consideration of psychological factors and patient focused education as an adjunct to these measures is paramount in developing a personalized perioperative pain management plan. Understanding the currently available body of knowledge surrounding perioperative opioid management, management of opioid use disorder, regional/neuraxial anesthetic techniques, ketamine/lidocaine infusions, non-opioid oral analgesics, and behavioral interventions can be useful in developing a comprehensive, multi-modal treatment plan among patients undergoing spine surgery. Although many of these techniques have proved efficacious in the immediate postoperative period, long-term follow-up is needed to define the impact of such approaches on persistent pain and opioid use. Future techniques involving the use of precision medicine may help identify phenotypic and physiologic characteristics that can identify patients that are most at risk of developing persistent postoperative pain after spine surgery.

Effect of intravenous lidocaine on propofol consumption in elderly patients undergoing colonoscopy: a double-blinded, randomized, controlled trial

BACKGROUND

Elderly patients undergoing colonoscopy with propofol as sedation are prone to respiratory or cardiovascular complications. Intravenous lidocaine has analgesic efficacy and reduces propofol consumption during surgery. Here, the effect of intravenous lidocaine on propofol consumption was evaluated in elderly patients undergoing colonoscopy.

METHODS

Patients were randomly allocated to receive intravenous lidocaine (1.5 mg/kg bolus dose, followed by a 2 mg/kg/h continuous infusion during the procedure; Group L) or a placebo (saline; Group N). During the procedure, sedation was achieved by propofol. The following outcomes were recorded: total propofol consumption; time to loss of consciousness; number of airway modifications; time to the first airway intervention; incidence of sedation-related events; pain score after awakening; endoscopists' and patients' satisfaction scores; memory level of the procedure; and adverse events within 24 h postoperatively.

RESULTS

Compared with Group N, propofol consumption was reduced by 13.2% in Group L (100.30 ± 25.29 mg vs. 115.58 ± 27.52 mg, respectively, p = 0.008). Kaplan-Meier curves showed that the median time to the loss of consciousness episode was shorter in Group L than in Group N (40 s vs. 55 s, respectively, log rank p < 0.0001). The number of airway modifications, time to the first airway intervention, incidence of sedation-related events, time to awakening, pain score after awakening, endoscopists' and patients' satisfaction scores, memory level of the procedure and adverse events within 24 h postoperatively did not differ between the two groups (p > 0.05).

CONCLUSIONS

Intravenous lidocaine can reduce propofol consumption in elderly patients undergoing colonoscopy, with quicker time to loss of consciousness.

TRIAL REGISTRATION

The clinical trial was registered at (12/01/2021, ChiCTR2100042001 ).

Lidocaine relieves murine allergic rhinitis by regulating the NF-κB and p38 MAPK pathways

Allergic rhinitis (AR) is one of the most common chronic inflammatory diseases and its main feature is nasal mucositis. It has been recently revealed that lidocaine demonstrates optimal effects in the treatment of various diseases. However, a limited number of studies have examined the association between lidocaine and AR. In the present study, the AR mouse model was established to explore the effects of lidocaine in AR and to further analyze its molecular mechanism. Subsequently, different concentrations of lidocaine were provided to the animals by intranasal administration and a series of indices were assessed. The data indicated that the frequencies of mouse sneezing and nose rubbing were suppressed following an increase in lidocaine concentration. Subsequently, the number of inflammatory cells was measured. Wright's-Giemsa staining results indicated that lidocaine significantly decreased the numbers of leukocytes, eosinophils, neutrophils and lymphocytes in the nasal lavage fluid (NLF) of AR mice. In addition, the expression levels of ovalbumin (OVA)-specific immunoglobulin E (IgE), leukotriene C4 (LTC4) and certain inflammatory factors were assessed by ELISA. Lidocaine reduced OVA-specific IgE and LTC4 expression in NLF and plasma derived from AR mice. It also decreased the expression levels of IL-4, IL-5, IL-13, IL-17 and TNF-α. Lidocaine caused upregulation of IFN-γ and IL-2 expression levels. Subsequently, western blot analysis indicated that lidocaine suppressed phosphorylated (p)-p38 and p-p65 expression levels in AR mice. Collectively, the results indicated that the NF-κB and p38 MAPK signaling pathways were involved in the lidocaine-mediated relief of AR in mice. In order to further verify the association between the NF-κB and p38 MAPK signaling pathways and AR in mice, the effects of the NF-κB inhibitor IMD-0354 and the p38 MAPK inhibitor SB 203580 were assessed on AR mice. The results indicated that these two compounds exhibited similar inhibitory effects on AR mice as those noted with the use of lidocaine. These findings suggested that lidocaine represented a novel therapeutic agent for AR.

Clinical Efficacy of Perioperative Intravenous Dexmedetomidine and Lidocaine Combined Infusion for Thyroidectomy: A Prospective, Randomized, Double-Blind, Placebo-Controlled Trial

OBJECTIVES

The aim of this study was to evaluate the efficacy of perioperative dexmedetomidine (DEX) combined with lidocaine intravenous infusion on relieving postoperative pain and improving recovery for patients undergoing thyroidectomy.

MATERIALS AND METHODS

A total of 138 patients undergoing thyroidectomy with general anesthesia were randomly divided into 4 groups: lidocaine (1.5 mg/kg bolus followed by 2 mg/kg/h infusion) in the group L, DEX (0.5 µg/kg) in the group D, lidocaine (same as the group L) with DEX (0.5 µg/kg) in the group L+D, and placebo as normal saline in the group C. All drugs were infused until the end of the surgery. The visual analog scale (VAS) scores of patients at 1, 4, 8, 12, and 24 hours following surgery, opioid requirement, propofol consumption, incidence of postoperative nausea and vomiting, awaking time, hemodynamic variables, and any adverse effects were assessed.

RESULTS

Compared with the group C, the VAS scores in the group L+D were significantly lower until 8 hours after surgery (P<0.05), while the VAS scores were significantly decreased just until 4 hours in the group L and 1 hour in the group D after surgery (P<0.05). There was no significant difference in opioid consumption between 4 groups. Propofol consumption in the group L+D was significantly lower than other groups (P<0.05). Compared with the group C, the incidence of postoperative nausea and vomiting in the group L+D was lower (P<0.05), and awaking time in the group L+D and the group L was shorter (P<0.05).

CONCLUSION

DEX combined with lidocaine infusion can effectively attenuate the postoperative pain without any serious adverse events, which may improve postoperative recovery in patients undergoing thyroidectomy.

Studies on local anesthetic lidocaine hydrochloride delivery via photo-triggered implantable polymeric microneedles as a patient-controlled transdermal analgesia system

This study aimed to develop photo-triggered implantable polymeric microneedles (MNs) for successful drug delivery in a transdermal analgesia system. The prepared iron oxide nanoparticles (Fe₃O₄NPs) were coated with polydopamine (PDA) followed by polyvinylpyrrolidone (PVP) and polycaprolactone (PCL). While the PCL/PVP-Fe₃O₄NPs synthesis, the absorption band of PVP at 1656 cm^-1 shifted to 1665 cm^-1 which indicate the presence of interaction between Fe⁺ and C = O groups. The size and morphology of PCL/PVP-Fe₃O₄NPs were examined by scanning electron microscope and transmission electron microscope (SEM and TEM) analysis. The results confirmed that the prepared PCL/PVP-Fe₃O₄NPs were spherical with sizes ranging from 9 to 11 nm. The lidocaine hydrochloride content in the microneedles was 3.72 ± 0.31 mg and A + 2.2S ≤ L representing that the drug was uniformly distributed. The insertion ability of lidocaine hydrochloride@PCL/PVP-Fe₃O₄NPs-DMNs was tested by porcine skin. The results demonstrated outstanding insertion ability and potential for drug delivery. In addition, near-infrared (NIR) irradiation has the potential to penetrate the skin and enhance lidocaine hydrochloride-releasing activity. The in vivo experimental data confirmed that lidocaine hydrochloride@PCL/PVP-Fe₃O₄NPs-DMNs allowed for painless drug delivery by breaking the barrier of the stratum corneum. To conclude, lidocaine hydrochloride can be safely delivered through the transdermal analgesic system, with a quick onset time.

Analysis of Airway Vagal Neurons

Internal organs, including the airway, are innervated by neurons of the autonomic and sensory nervous systems. The airway-innervating sensory neurons primarily originate from the vagus nerve, whose cell bodies are found, in rodents, in the jugular and nodose ganglia complex (JNC). About half of these sensory neurons expressed the heat-sensing ion channel TRPV1 and evolved to limit tissue damage by detecting chemical, mechanical, or thermal threats and to initiate protective airway reflexes such as coughing and bronchoconstriction. They also help monitor the host homeostasis by sensing nutrients, pressure, and O₂ levels and help mount airway defenses by controlling immune and goblet cell activity. To better appreciate the scope of the physiological role and pathological contributions of these neurons, we will review gain and loss-of-function approaches geared at controlling the activity of these neurons. We will also present a method to study transcriptomic changes in airway-innervating neurons and a co-culture approach designed to understand how nociceptors modulate immune responses.

Computational design of peptides to target NaV1.7 channel with high potency and selectivity for the treatment of pain

The voltage-gated sodium Na_V1.7 channel plays a key role as a mediator of action potential propagation in C-fiber nociceptors and is an established molecular target for pain therapy. ProTx-II is a potent and moderately selective peptide toxin from tarantula venom that inhibits human Na_V1.7 activation. Here we used available structural and experimental data to guide Rosetta design of potent and selective ProTx-II-based peptide inhibitors of human Na_V1.7 channels. Functional testing of designed peptides using electrophysiology identified the PTx2-3127 and PTx2-3258 peptides with IC₅₀s of 7 nM and 4 nM for hNa_V1.7 and more than 1000-fold selectivity over human Na_V1.1, Na_V1.3, Na_V1.4, Na_V1.5, Na_V1.8, and Na_V1.9 channels. PTx2-3127 inhibits Na_V1.7 currents in mouse and human sensory neurons and shows efficacy in rat models of chronic and thermal pain when administered intrathecally. Rationally designed peptide inhibitors of human Na_V1.7 channels have transformative potential to define a new class of biologics to treat pain.

Postoperative Pain Management in Enhanced Recovery Pathways

Postoperative pain is a common but often inadequately treated condition. Enhanced recovery pathways (ERPs) are increasingly being utilized to standardize perioperative care and improve outcomes. ERPs employ multimodal postoperative pain management strategies that minimize opioid use and promote recovery. While traditional opioid medications continue to play an important role in the treatment of postoperative pain, ERPs also rely on a wide range of non-opioid pharmacologic therapies as well as regional anesthesia techniques to manage pain in the postoperative setting. The evidence for the use of these interventions continues to evolve rapidly given the increasing focus on enhanced postoperative recovery. This article reviews the current evidence and knowledge gaps pertaining to commonly utilized modalities for postoperative pain management in ERPs.

Pain Management Considerations in Patients with Opioid Use Disorder Requiring Critical Care

The opioid epidemic has resulted in increased opioid-related critical care admissions, presenting challenges in acute pain management. Limited guidance exists in the management of critically ill patients with opioid use disorder (OUD). This narrative review provides the intensive care unit (ICU) clinician with guidance and treatment options, including non-opioid analgesia, for patients receiving medications for opioid use disorder (MOUD) and for patients actively misusing opioids. Verification and continuation of the patient's outpatient MOUD regimen, specifically buprenorphine and methadone formulations, assessment of pain and opioid withdrawal, and treatment of acute pain with non-opioid analgesia, nonpharmacologic strategies, and short-acting opioids as needed, are all essential to adequate management of acute pain in patients with OUD. A multidisciplinary approach to treatment and discharge planning in patients with OUD may be beneficial to engage patients with OUD early in their hospital stay to prevent withdrawal, stabilize their OUD, and to reduce the risk of unplanned discharge and other associated morbidity. This article is protected by copyright. All rights reserved.

Materials Chemistry of Neural Interface Technologies and Recent Advances in Three-Dimensional Systems

Advances in materials chemistry and engineering serve as the basis for multifunctional neural interfaces that span length scales from individual neurons to neural networks, neural tissues, and complete neural systems. Such technologies exploit electrical, electrochemical, optical, and/or pharmacological modalities in sensing and neuromodulation for fundamental studies in neuroscience research, with additional potential to serve as routes for monitoring and treating neurodegenerative diseases and for rehabilitating patients. This review summarizes the essential role of chemistry in this field of research, with an emphasis on recently published results and developing trends. The focus is on enabling materials in diverse device constructs, including their latest utilization in 3D bioelectronic frameworks formed by 3D printing, self-folding, and mechanically guided assembly. A concluding section highlights key challenges and future directions.

Acute Visceral Pain in Rats: Vagal Nerve Block Compared to Bupivacaine Administered Intramuscularly

BACKGROUND

Visceral and parietal peritoneum layers have different sensory innervations. Most visceral peritoneum sensory information is conveyed via the vagus nerve to the nucleus of the solitary tract (NTS). We already showed in animal models that intramuscular (i.m.) injection of local anesthetics decreases acute somatic and visceral pain and general inflammation induced by aseptic peritonitis. The goal of the study was to compare the effects of parietal block, i.m. bupivacaine, and vagotomy on spinal cord and NTS stimulation induced by a chemical peritonitis.

METHODS

We induced peritonitis in rats using carrageenan and measured cellular activation in spinal cord and NTS under the following conditions, that is, a parietal nerve block with bupivacaine, a chemical right vagotomy, and i.m. microspheres loaded with bupivacaine. Proto-oncogene c-Fos (c-Fos), cluster of differentiation protein 11b (CD11b), and tumor necrosis factor alpha (TNF-α) expression in cord and NTS were studied.

RESULTS

c-Fos activation in the cord was inhibited by nerve block 2 hours after peritoneal insult. Vagotomy and i.m. bupivacaine similarly inhibited c-Fos activation in NTS. Forty-eight hours after peritoneal insult, the number of cells expressing CD11b significantly increased in the cord (P = .010). The median difference in the effect of peritonitis compared to control was 30 cells (CI95, 13.5-55). TNF-α colocalized with CD11b. Vagotomy inhibited this microglial activation in the NTS, but not in the cord. This activation was inhibited by i.m. bupivacaine both in cord and in NTS. The median difference in the effect of i.m. bupivacaine added to peritonitis was 29 cells (80% increase) in the cord and 18 cells (75% increase) in the NTS. Our study underlines the role of the vagus nerve in the transmission of an acute visceral pain message and confirmed that systemic bupivacaine prevents noxious stimuli by inhibiting c-Fos and microglia activation.

CONCLUSIONS

In rats receiving intraperitoneal carrageenan, i.m. bupivacaine similarly inhibited c-Fos and microglial activation both in cord and in the NTS. Vagal block inhibited activation only in the NTS. Our study underlines the role of the vagus nerve in the transmission of an acute visceral pain message and confirmed that systemic bupivacaine prevents noxious stimuli. This emphasizes the effects of systemic local anesthetics on inflammation and visceral pain.

Association between perioperative intravenous lidocaine and subjective quality of recovery: A meta-analysis of randomized controlled trials

STUDY OBJECTIVE

To evaluate the impact of perioperative intravenous lidocaine on the quality of recovery (QoR) following surgery.

DESIGN

Meta-analysis of randomized controlled trials (RCTs).

SETTING

Postoperative care.

INTERVENTION

Intravenous lidocaine during perioperative period.

PATIENTS

Adults undergoing surgery under general anesthesia.

MEASUREMENTS

The primary outcome was postoperative QoR measured with QoR-40 questionnaire, while the secondary outcomes included five individual dimensions (i.e., emotional, state, physical comfort, psychological support, physical independence, and pain) of QoR-40, intraoperative opioid consumption, and risk of chronic postsurgical pain (CPSP).

MAIN RESULTS

Medline, Cochrane Library, Google scholar, and EMBASE databases were searched from inception to June 2021. Fourteen RCTs involving 1148 patients in total undergoing elective surgery published from 2012 to 2021 were included. QoR-40 scores were evaluated at postoperative 24 h (12 trials), 72 h (one trial), and Day 5 (one trial), respectively. Pooled results revealed significantly higher global [mean difference (MD) = 9.65, 95% confidence interval (CI): 6.33 to 12.97; I² = 97%; 13 RCTs; n = 1085] and individual dimension QoR-40 scores in the lidocaine group than those in placebo group. Subgroup analysis demonstrated no significant impact of the type of surgery, age, gender, surgical time, anesthetic technique, lidocaine dosage, and time of assessment on global QoR-40 scores. The use of intravenous lidocaine was associated with a significant reduction in intraoperative remifentanil consumption compared with that in the placebo group (standardized MD = -0.91, 95%CI: -1.32 to -0.51; I² = 86%; 10 RCTs; n = 799). There was no difference in risk of CPSP between the two groups [relative risk (RR) = 0.65, 95%CI: 0.33 to 1.25; I² = 58%; 4 RCTs; n = 309].

CONCLUSION

Our results verified the efficacy of intravenous lidocaine for enhancing postoperative quality of recovery by using a validated subjective tool and reducing intraoperative remifentanil consumption in patients receiving elective surgery under general anesthesia. Further studies are warranted to verify its efficacy in the acute care setting.

Effects of intravenous lidocaine on alfentanil consumption during procedural sedation for colonoscopy in patients with inflammatory bowel disease: a randomized controlled trial

Background: Procedural sedation and analgesia (PSA) is used during colonoscopy to facilitate the procedure and relieve patient’s discomfort. The foremost risk of PSA is respiratory depression. Lidocaine could be a promising additional analgesic in IBD patients to minimise side effects of PSA. Objective: Our primary objective was to investigate whether i.v. lidocaine reduces the amount of alfentanil used during PSA in IBD patients. Additionally, we investigated whether lidocaine reduces cardiorespiratory incidents and the amount of propofol required during the procedure. Design: A randomized, double-blind, placebo controlled study. Setting: Single-center study from November 2016 to December 2018. Methods: Seventy-six patients with IBD, ASA 1 or 2, between 18 and 65 years, scheduled for colonoscopy with PSA were included. Exclusion criteria were: pregnancy, emergency colonoscopy, allergies for study medication, rhythm disorders, cardiomyopathy, BMI < 18 kg m -2 , BMI > 35 kg m -2 , obstructive sleep apnea syndrome and uncontrolled hypertension. Patients received lidocaine 1.5 mg kg -1 followed by a continuous infusion of 2 mg kg -1 h -1 (intervention group, n=38) or 0.9% saline in equivalent volumes (control group, n=38) during colonoscopy. Main outcome measures: Amount of alfentanil and propofol used during the interventional procedure. Cardiorespiratory events as defined in methods during the colonoscopy. Results: There was a not statistically significant reduction in the use of alfentanil [327 µg (95%CI=-31-505, p=0.082)] and propofol [39 mg (95%CI=-5-83, p=0.083)] in the lidocaine group compared with the control group. Ten patients (26%) in the control group and 8 patients in the lidocaine group (21%) experienced a period of hypoxia (p=0.788). In both groups, no periods of hypotension were noted. Conclusion: Our investigation has shown a trend for reduced alfentanil and propofol consumption in patients receiving lidocaine during colonoscopy under sedation. The differences were not statistically significant. Lidocaine did not reduce the incidence of cardiorespiratory events.

Association between chronic pain medications and the severity and mortality of COVID-19: Study protocol for a case-population study

In patients with coronavirus disease 2019 (COVID-19) infection, common drugs may exacerbate symptoms and negatively impact outcomes. However, the role of chronic medications on COVID-19 effects remains poorly understood. We hypothesized that certain chronic pain medications would influence outcomes in patients with COVID-19. The main aim is to assess the effect of these medications on the course of the disease in COVID-19 patients. Secondary aims are to compare disease severity and outcomes in patients with COVID-19 receiving chronic treatment with analgesics or other medications versus untreated patients and to determine prevalence of chronic pain medications in specific subgroups of hospitalized patients for COVID-19. Multicenter case-population study in 15 care centers for patients ≥18 years of age diagnosed and hospitalized with COVID-19. Controls will include patients treated at participating centers for chronic pain during the six-month period prior to March 15th, 2020. Each case will be age- and sex-matched to 10 controls. Patients will be grouped according to disease severity criteria. The primary outcome measures in patients admitted for COVID-19 will be: 1. statistical association between chronic pain medication and disease severity; 2. association between chronic pain treatment and survival. Secondary outcome measures include: 1. prevalence of chronic pain medications in patients with COVID-19 by age and sex; 2. prevalence of chronic pain medications in patients with COVID-19 vs controls. Patients and controls will be paired by age, sex, and geographic residence. Odds ratios with 95% confidence intervals will be calculated to determine the association between each drug and clinical status. Univariate and multivariate analyses will be performed. This is a study protocol. Data is actually being gathered and results are yet not achieved. There is no numerical data presented, so the conclusions cannot be considered solid at this point. Pain medications are likely to influence severity of COVID-19 and patient survival. Identifying those medications that are most closely associated with severe COVID-19 will provide clinicians with valuable data to guide treatment and reduce mortality rates and the long-term sequelae of the disease.

Mechanisms of action of fascial plane blocks: a narrative review

BACKGROUND

Fascial plane blocks (FPBs) target the space between two fasciae, rather than discrete peripheral nerves. Despite their popularity, their mechanisms of action remain controversial, particularly for erector spinae plane and quadratus lumborum blocks.

OBJECTIVES

This narrative review describes the scientific evidence underpinning proposed mechanisms of action, highlights existing knowledge gaps, and discusses implications for clinical practice and research.

FINDINGS

There are currently two plausible mechanisms of analgesia. The first is a local effect on nociceptors and neurons within the plane itself or within adjacent muscle and tissue compartments. Dispersion of local anesthetic occurs through bulk flow and diffusion, and the resulting conduction block is dictated by the mass of local anesthetic reaching these targets. The extent of spread, analgesia, and cutaneous sensory loss is variable and imperfectly correlated. Explanations include anatomical variation, factors governing fluid dispersion, and local anesthetic pharmacodynamics. The second is vascular absorption of local anesthetic and a systemic analgesic effect at distant sites. Direct evidence is presently lacking but preliminary data indicate that FPBs can produce transient elevations in plasma concentrations similar to intravenous lidocaine infusion. The relative contributions of these local and systemic effects remain uncertain.

CONCLUSION

Our current understanding of FPB mechanisms supports their demonstrated analgesic efficacy, but also highlights the unpredictability and variability that result from myriad factors at play. Potential strategies to improve efficacy include accurate deposition close to targets of interest, injections of sufficient volume to encourage physical spread by bulk flow, and manipulation of concentration to promote diffusion.

Local Anesthetic Lidocaine and Cancer: Insight Into Tumor Progression and Recurrence

Cancer is a leading contributor to deaths worldwide. Surgery is the primary treatment for resectable cancers. Nonetheless, it also results in inflammatory response, angiogenesis, and stimulated metastasis. Local anesthetic lidocaine can directly and indirectly effect different cancers. The direct mechanisms are inhibiting proliferation and inducing apoptosis via regulating PI3K/AKT/mTOR and caspase-dependent Bax/Bcl2 signaling pathways or repressing cytoskeleton formation. Repression invasion, migration, and angiogenesis through influencing the activation of TNFα-dependent, Src-induced AKT/NO/ICAM and VEGF/PI3K/AKT signaling pathways. Moreover, the indirect influences are immune regulation, anti-inflammation, and postoperative pain relief. This review summarizes the latest evidence that revealed potential clinical benefits of lidocaine in cancer treatment to explore the probable molecular mechanisms and the appropriate dose.

Repeated Intravenous Lidocaine Infusions for Patients with Fibromyalgia: Higher Doses of Lidocaine Have a Stronger and Longer-Lasting Effect on Pain Reduction

OBJECTIVES

To determine the effect of escalating doses of lidocaine infusion with or without added magnesium on pain levels and the duration of pain relief in patients with fibromyalgia (FM).

METHODS

A retrospective chart review of 74 patients diagnosed with FM who underwent at least three escalating doses of intravenous (IV) lidocaine infusions (5 mg/kg of body weight, 7.5 mg/kg, and 7.5 mg/kg of lidocaine + 2.5 g of magnesium sulfate) was conducted. Each patient's subjective impression of change in pain intensity and duration of pain relief after each treatment was recorded, along with an 11-point numeric rating scale (NRS) for pain intensity, immediately before and after each infusion.

RESULTS

Short-term lidocaine analgesia was evaluated by the reduction in NRS pain score according to the patients reported pre- (immediately before treatment) and post-treatment (immediately after treatment) values. There was a statistical difference in the NRS score reduction between doses 5 mg/kg and 7.5 mg/kg of lidocaine (P = 0.009). Long-term analgesia was evaluated at follow-up visits by the patient's subjective impression of change in pain intensity and duration of pain relief. There was a statistical difference in the percentage of pain relief and the mean duration of pain relief between the treatments with 5 mg/kg and 7.5 mg/kg of lidocaine (P = 0.007 and P = 0.003). Although there was a trend of greater response to magnesium sulfate as a beneficial adjunct to the lidocaine infusion, we were unable to find a statistically significant difference for any of the variables studied.

CONCLUSIONS

This study demonstrated that escalating doses of IV lidocaine to 7.5 mg/kg safely and effectively reduced the pain with prolonged effect in a significant number of patients diagnosed with fibromyalgia. Larger, prospective clinical studies are required to confirm this finding.

Lidocaine coinfusion alleviates vascular pain induced by hypertonic saline infusion: a randomized, placebo-controlled trial

Background

Hypertonic saline solution has been frequently utilized in clinical practice. However, due to the nonphysiological osmolality, hypertonic saline infusion usually induces local vascular pain. We conducted this study to evaluate the effect of lidocaine coinfusion for alleviating vascular pain induced by hypertonic saline.

Methods

One hundred and six patients undergoing hypertonic saline volume preloading prior to spinal anesthesia were randomly allocated to two groups of 53 each. Group L received a 1 mg/kg lidocaine bolus followed by infusion of 2 mg/kg/h through the same IV line during hypertonic saline infusion; Group C received a bolus and infusion of normal saline of equivalent volume. Visual analogue scale (VAS) scores of vascular pain were recorded every 4 min.

Results

The vascular pain severity in Group L was significantly lower than that in Group C for each time slot (P < 0.05). The overall incidence of vascular pain during hypertonic saline infusion in Group L was 48.0%, which was significantly lower than the incidence (79.6%) in Group C (P < 0.05).

Conclusion

Lidocaine coinfusion could effectively alleviate vascular pain induced by hypertonic saline infusion.

Trial registration

Chinese Clinical Trial Registry, number: ChiCTR1900023753. Registered on 10 June 2019.

Topical Treatments and Their Molecular/Cellular Mechanisms in Patients with Peripheral Neuropathic Pain-Narrative Review

Neuropathic pain in humans results from an injury or disease of the somatosensory nervous system at the peripheral or central level. Despite the considerable progress in pain management methods made to date, peripheral neuropathic pain significantly impacts patients' quality of life, as pharmacological and non-pharmacological methods often fail or induce side effects. Topical treatments are gaining popularity in the management of peripheral neuropathic pain, due to excellent safety profiles and preferences. Moreover, topical treatments applied locally may target the underlying mechanisms of peripheral sensitization and pain. Recent studies showed that peripheral sensitization results from interactions between neuronal and non-neuronal cells, with numerous signaling molecules and molecular/cellular targets involved. This narrative review discusses the molecular/cellular mechanisms of drugs available in topical formulations utilized in clinical practice and their effectiveness in clinical studies in patients with peripheral neuropathic pain. We searched PubMed for papers published from 1 January 1995 to 30 November 2020. The key search phrases for identifying potentially relevant articles were "topical AND pain", "topical AND neuropathic", "topical AND treatment", "topical AND mechanism", "peripheral neuropathic", and "mechanism". The result of our search was 23 randomized controlled trials (RCT), 9 open-label studies, 16 retrospective studies, 20 case (series) reports, 8 systematic reviews, 66 narrative reviews, and 140 experimental studies. The data from preclinical studies revealed that active compounds of topical treatments exert multiple mechanisms of action, directly or indirectly modulating ion channels, receptors, proteins, and enzymes expressed by neuronal and non-neuronal cells, and thus contributing to antinociception. However, which mechanisms and the extent to which the mechanisms contribute to pain relief observed in humans remain unclear. The evidence from RCTs and reviews supports 5% lidocaine patches, 8% capsaicin patches, and botulinum toxin A injections as effective treatments in patients with peripheral neuropathic pain. In turn, single RCTs support evidence of doxepin, funapide, diclofenac, baclofen, clonidine, loperamide, and cannabidiol in neuropathic pain states. Topical administration of phenytoin, ambroxol, and prazosin is supported by observational clinical studies. For topical amitriptyline, menthol, and gabapentin, evidence comes from case reports and case series. For topical ketamine and baclofen, data supporting their effectiveness are provided by both single RCTs and case series. The discussed data from clinical studies and observations support the usefulness of topical treatments in neuropathic pain management. This review may help clinicians in making decisions regarding whether and which topical treatment may be a beneficial option, particularly in frail patients not tolerating systemic pharmacotherapy.

Post-partum relapse in women with multiple sclerosis after neuraxial labour analgesia or neuraxial anaesthesia: A multicentre retrospective cohort study

BACKGROUND

The proportion of women with multiple sclerosis experiencing a relapse in the post-partum period after neuraxial labour analgesia or neuraxial anaesthesia remains uncertain. This study aimed to assess the association between neuraxial labour analgesia or neuraxial anaesthesia and the occurrence of relapse during the first three months post-partum.

METHODS

In this retrospective cohort study, cases of women with a diagnosis of multiple sclerosis delivering between January 2010 and April 2015 were analysed. Demographic, anaesthetic and obstetric characteristics, occurrence and number of relapses in the year preceding pregnancy, during pregnancy, and the first three post-partum months, were recorded. Logistic regression analyses were performed for the identification of factors associated with the occurrence of post-partum relapse.

RESULTS

A total of 118 deliveries in 104 parturients were included, these were 78 (66%) vaginal deliveries and 40 (34%) caesarean deliveries. Neuraxial analgesia was provided in 50 deliveries, and neuraxial anaesthesia in 46 deliveries; no neuraxial anaesthesia or analgesia was administered in remaining 22 deliveries. Post-partum relapse occurred in 31 women (26%). There was no association between obstetric or anaesthetic characteristics and post-partum relapse. Both the occurrence and number of relapses prior to and during pregnancy, and the time between last relapse and delivery, were significantly associated with post-partum relapse in univariate analysis. The occurrence of relapse within the year preceding the pregnancy was the sole independent factor associated with post-partum relapse.

CONCLUSION

Neuraxial procedures were not associated with increased rate of post-partum relapse; only disease activity prior to pregnancy was predictive of post-partum relapse.

Efficacy and Long-term Effect of Radiofrequency Denervation in Patients with Clinically Diagnosed Cervical Facet Joint Pain: A Double-blind Randomized Controlled Trial

STUDY DESIGN

Multicenter double-blind randomized sham-controlled trial.

OBJECTIVE

To assess the efficacy of radiofrequency (RF) denervation of the cervical facet joints in chronic cervical facet joint pain.

SUMMARY OF BACKGROUND DATA

One randomized controlled trial showed efficacy of RF denervation in whiplash-associated disease. There are no randomized controlled trials on RF denervation in patients with chronic cervical facet joint pain.

METHODS

Patients were randomized to receive RF denervation combined with bupivacaine (intervention group) or bupivacaine alone (control group). In the intervention group, an RF thermal lesion was made at the cervical medial branches after the injection of bupivacaine. The primary outcome was measured at 6 months and consisted of pain intensity, self-reported treatment effect, improvement on the Neck Disability Index, and the use of pain medication. Duration of effect was determined using telephone interviews.

RESULTS

We included 76 patients. In the intervention group, 55.6% showed > 30% pain decrease versus 51.3% in the control group (P = 0.711); 50.0% reported success on the Patients' Global Impression of Change in the intervention group versus 41.0% (P = 0.435); the Neck Disability Index was 15.0 ± 8.7 in the intervention group compared with 16.5 ± 7.2 (P = 0.432), the need for pain medication did not differ significantly between groups (P = 0.461). The median time to end of treatment success for patients in the RF group was 42 months, compared with 12 months in the bupivacaine group (P = 0.014).

CONCLUSIONS

We did not observe significant differences between RF denervation combined with injection of local anesthesia compared with local anesthesia only at 6 months follow-up. We found a difference in the long-term effect after 6 months follow-up in favor of the RF treatment.Level of Evidence: 2.

Lidocaine attenuates CFA-induced inflammatory pain in rats by regulating the MAPK/ERK/NF-κB signaling pathway

Lidocaine is a commonly used local anesthetic that also confers analgesic effects, resistance to hyperalgesia and anti-inflammatory properties. The present study aimed to explore the effects of lidocaine on complete Freund's adjuvant (CFA)-induced inflammatory pain. In the present study, rats were subcutaneously injected with CFA to investigate the molecular mechanisms associated with lidocaine in an inflammation-induced pain model. Firstly, CFA was subcutaneously injected into the paws of Sprague-Dawley rats, following which lidocaine or saline and the ERK agonist recombinant human epidermal growth factor (rh-EGF) were injected via the tail vein. Rat behavior was then assessed at 0 and 4 h, 1, 4, 7 and 14 days after CFA treatment. Proinflammatory cytokine levels in the serum were measured using ELISA. Western blotting was performed to detect the protein levels of phosphorylated (p)-ERK1/2, ERK1/2 and NF-κB subunits p-p65 and p65. Reverse transcription-quantitative PCR was used to measure the mRNA expression of ERK1/2 and p65 in rat spinal cord tissues. The results showed that injection of CFA significantly reduced the mechanical withdrawal threshold, thermal withdrawal latency and the frequency of responses to cold stimulation in rats, whilst promoting tumor necrosis factor-α, interleukin (IL)-1β, IL-6 levels in addition to ERK1/2, p65 protein phosphorylation. These effects were alleviated by lidocaine treatment. Furthermore, treatment with rh-EGF reversed the protective effects of lidocaine on inflammatory pain caused by CFA. In conclusion, lidocaine inhibits the inflammatory response and pain through the MAPK/ERK/NF-κB pathway in a rat model of pain induced by CFA.

Wirelessly controlled, bioresorbable drug delivery device with active valves that exploit electrochemically triggered crevice corrosion

Implantable drug release platforms that offer wirelessly programmable control over pharmacokinetics have potential in advanced treatment protocols for hormone imbalances, malignant cancers, diabetic conditions, and others. We present a system with this type of functionality in which the constituent materials undergo complete bioresorption to eliminate device load from the patient after completing the final stage of the release process. Here, bioresorbable polyanhydride reservoirs store drugs in defined reservoirs without leakage until wirelessly triggered valve structures open to allow release. These valves operate through an electrochemical mechanism of geometrically accelerated corrosion induced by passage of electrical current from a wireless, bioresorbable power-harvesting unit. Evaluations in cell cultures demonstrate the efficacy of this technology for the treatment of cancerous tissues by release of the drug doxorubicin. Complete in vivo studies of platforms with multiple, independently controlled release events in live-animal models illustrate capabilities for control of blood glucose levels by timed delivery of insulin.

Acute Cytokine Response During Breast Cancer Surgery: Potential Role of Dexamethasone and Lidocaine and Relationship with Postoperative Pain and Complications - Analysis of Three Pooled Pilot Randomized Controlled Trials

Purpose

An imbalance in perioperative cytokine response may cause acute pain and postoperative complications. Anesthetic drugs modulate this cytokine response, but their role in non-major breast cancer surgery is unclear. In an exploratory study, we investigated whether intravenous lidocaine and dexamethasone could modulate the cytokine response into an anti-inflammatory direction. We also evaluated interrelationships between cytokine levels, pain scores and postoperative complications. Our goal is to develop multimodal analgesia regimens optimizing outcome after breast cancer surgery.

Patients and Methods

Forty-eight patients undergoing a lumpectomy were randomly assigned to placebo or lidocaine (1.5 mg⋅kg⁻¹ followed by 2 mg⋅kg⁻¹⋅hour⁻¹) supplemented by dexamethasone zero, 4 or 8 mg, yielding six groups of eight patients. Interleukin (IL)-1β, IL-1Ra, IL-6, IL-10 levels and pain scores were measured at baseline and four hours postoperatively. We assessed postoperative complications occurring within 30 days. We noted persistent pain and infections as potential immune-related complications (PIRC). We used multiple regression to disentangle the effects of the individual study drugs (given by their partial regression coefficients (b)). Odds ratios (OR) estimated the link between pain scores and complications.

Results

Dexamethasone 8 mg increased IL-10 (b=12.70 (95% CI=8.06–17.34), P<0.001). Dexamethasone 4 mg and 8 mg decreased the ratio IL-6/IL-10 (b=−2.60 (−3.93 to −1.26), P<0.001 and b=−3.59 (−5.04 to −2.13), P<0.001, respectively). We could not show modulatory effects of lidocaine on cytokines. High pain scores were linked to the occurrence of PIRC’s (OR=2.028 (1.134–3.628), P=0.017). Cytokine levels were not related either to acute pain or PIRC.

Conclusion

Dexamethasone modulated the perioperative cytokine response into an anti-inflammatory direction. An overall lidocaine effect was not found. Patients with higher pain scores suffered from more 30-day PIRCs. Cytokine levels were not associated with pain or more postoperative complications, even not with PIRC. Larger studies in breast cancer surgery are needed to confirm these explorative results.

Lidocaine as an element of multimodal analgesic therapy in major spine surgical procedures in children: a prospective, randomized, double-blind study

Background

Introducing the principles of multimodal analgesic therapy is necessary to provide appropriate comfort for the patient after surgery. The main objective of the study was evaluating the influence of perioperative intravenous (i.v.) lidocaine infusion on postoperative morphine requirements during the first 48 h postoperatively in children undergoing major spine surgery.

Materials and methods

Prospective, randomized, double-blind study: 41 children, qualified to multilevel spine surgery, were randomly divided into two treatment groups: lidocaine and placebo (control). The lidocaine group received lidocaine as a bolus of 1.5 mg/kg over 30 minutes, followed by a continuous infusion at 1 mg/kg/h to 6 hours after surgery. The protocol of perioperative management was identical for all patients. Measurements: morphine demand, intensity of postoperative pain (the Numerical Rating Scale), oral feeding initiation time, first attempts at assuming erect position, postoperative quality of life (the Acute Short-form /SF-12/ health survey).

Results

Patient data did not differ demographically. Compared to the control group, lidocaine treatment reduced the demand for morphine during the first 24h [95% CI 0.13 (0.11-0.28) mg/kg, p = 0.0122], 48h [95% CI 0.46 (0.22-0.52) mg/kg, p = 0.0299] after surgery and entire hospitalization [95% CI 0.58 (0.19-0.78) mg/kg, p = 0.04]; postoperative pain intensity; nutritional withdrawal period [introduction of liquid diet (p = 0.024) and solid diet (p = 0.012)], and accelerated the adoption of an upright position [sitting (p = 0.048); walking (p = 0.049)]. The SF-12 generic health survey did not differ between groups before operation, 2 months and 4 years after surgery.

Conclusions

Perioperative lidocaine administration, as a part of the applied analgesic therapy regimen, may decrease postoperative opioid demand and accelerates convalescence of children undergoing major surgery.

Intravenous lidocaine affects oxaliplatin pharmacokinetics in simultaneous infusion

BACKGROUND

Oxaliplatin is a chemotherapeutic agent used to treat malignancies of the gastrointestinal tract. Neuropathy is a frequent dose-limiting side-effect of oxaliplatin therapy, without preventive or curative strategies. Concomitant administration of intravenous lidocaine could be a promising treatment. However, the effect of intravenous lidocaine on oxaliplatin pharmacokinetics was never studied before. We evaluated the effect of lidocaine on the area under the curve and C_max of oxaliplatin as a part of a larger study addressing the prevention and treatment of oxaliplatin induced peripheral neuropathy with lidocaine.

METHODS

In this prospective cross-over trial, patients received an oxaliplatin cycle with and without lidocaine (bolus 1.5 mg kg^-1 followed by 1.5 mg kg^-1 h^-1 in 3 h). Levels of oxaliplatin, measured as ultrafiltrable platinum were determined at 10 min after cessation of oxaliplatin infusion and hourly thereafter. Outcomes are the difference in area under the curve of oxaliplatin (primary) and the difference in the C_max of oxaliplatin (secondary).

RESULTS

No difference in the %Δ area under the curve of oxaliplatin (-2.40 ± 7.66, 90% CI +10.50 to -15.31) was found. However, %Δ C_max of oxaliplatin (-28.72 ± 6.01, 90% CI -18.59 to -38.85) was lower to a statistically significant extent in the chemotherapy cycle with lidocaine. No (serious) adverse events were reported.

CONCLUSIONS

Lidocaine does not affect the area under the curve of oxaliplatin, which is the most important parameter in drug interaction studies and for oxaliplatin treatment effect. The lower C_max in the chemotherapeutic cycle with lidocaine is significant and remarkable, but with an unknown exact mechanism or clinical significance, making further research desirable.

HPLC-MS/MS measurement of lidocaine in rat skin and plasma. Application to study the release from medicated plaster

A simple, sensitive HPLC-MS/MS method was developed and validated for the determination of lidocaine in skin and plasma of rats. The methods were established and validated assessing lower limit of quantitation (LLOQ), linearity, intra and inter-day precision and accuracy, selectivity, recovery and matrix effect. Chromatography was done on a Gemini column embedded with C18 stationary phase (50 mm × 2.0 mm, 5 µm particle size), using a gradient with mobile phases consisting of 0.1% HCOOH in bidistilled water and 0.1% HCOOH in acetonitrile. The mass spectrometer worked with electrospray ionization in positive ion mode and selected reaction monitoring, using target ions m/z 235.10 for lidocaine and m/z 245.10 for lidocaine-d10, used as internal standard. RESULTS: The linearity of the method was in the ranges of lidocaine concentrations 10.0-200.0 ng/mL for skin homogenate (accuracy 94.1-105.5%; R² ≥ 0.998) and 0.025-2 ng/mL for plasma (accuracy 96.2-104.8%; R² ≥ 0.996). The intra- and inter-day precision and accuracy determined on three quality control samples (20, 75 and 170 ng/mL for skin and 0.075, 0.4 and 1.5 ng/mL for plasma) were ≤4.2% and 103.8-108.2% for skin and ≤12.4% and 95.5-101.4% for plasma. The LLOQ was 10 ng/mL in skin homogenate and 0.025 ng/mL in plasma. The applicability of the method was demonstrated by measuring lidocaine in skin and plasma after exposure to medicated patches containing 5% lidocaine.

A survey of perioperative intravenous lidocaine use by anaesthetists in Australia and New Zealand

Perioperative intravenous lidocaine administration by anaesthetists is purported to confer a variety of benefits across a range of surgical procedures. It remains unclear whether the available evidence regarding efficacy and safety is sufficient to influence Australasian practice broadly, and whether significant barriers to uptake exist. We therefore conducted a survey of Fellows of the Australian and New Zealand College of Anaesthetists to evaluate patterns of lidocaine use, and perceptions relating to benefit and safety. Of 979 survey invitations, 295 (30.1%) responded. Of these, 51.9% of anaesthetists incorporate lidocaine administration into their practice. Amongst users, the most common indication is open abdominal or pelvic surgery (88.9%), with the principal intent of reducing acute pain and opioid use (both 92.2%). Only 51% perceive lidocaine to have a role in the prevention of chronic post-surgical pain, and less than a third administer it for operations strongly linked to this condition. Nearly all (91%) users deliver the drug by intraoperative bolus and infusion, with the majority using doses between 1.0 and 1.5 mg/kg for both the bolus and the hourly infusion rate. When parallel local anaesthetic techniques are employed, 44.4% restrict the dose, 37.3% turn the lidocaine infusion off first and 15.7% make no modifications. Most respondents terminate infusions by the end of surgery (52.3%) or in the post-anaesthesia care unit (26.8%). Few deliver postoperative infusions without electrocardiographic monitoring (5.9%). There were no reports of life-threatening events. The dichotomy in Australasian use of perioperative lidocaine revealed by this survey confirms that large multicentre trials are now required to guide practice accurately.

Neurological dysfunction after cardiac surgery and cardiac intensive care admission: A narrative review part 2: Cognitive dysfunction after critical illness; potential contributors in surgery and intensive care; pathogenesis; and therapies to prevent/treat perioperative neurological dysfunction

Severe cognitive decline and cognitive dysfunction has been attributed to patient's stay in the cardiovascular intensive care unit. Prolonged mechanical ventilation, long duration of stay, sedation protocols, and sleep deprivation contribute to patients developing neurocognitive disorder after intensive care admission and it is associated with poor clinical outcomes. Trauma of surgery, stress of critical care, and administration of anaesthesia evoke a systemic inflammatory response and trigger neuroinflammation and oxidative stress. Anaesthetic agents modulate the function of the GABA receptors. The persistence of these effects in the postoperative period promotes development of cognitive dysfunction. A number of drugs are under investigation to restrict or prevent this cognitive decline.

Impact of perioperative pain management on cancer recurrence: an ASRA/ESRA special article

Cancer causes considerable suffering and 80% of advanced cancer patients experience moderate to severe pain. Surgical tumor excision remains a cornerstone of primary cancer treatment, but is also recognized as one of the greatest risk factors for metastatic spread. The perioperative period, characterized by the surgical stress response, pharmacologic-induced angiogenesis, and immunomodulation results in a physiologic environment that supports tumor spread and distant reimplantation.In the perioperative period, anesthesiologists may have a brief and uniquewindow of opportunity to modulate the unwanted consequences of the stressresponse on the immune system and minimize residual disease. This reviewdiscusses the current research on analgesic therapies and their impact ondisease progression, followed by an evidence-based evaluation of perioperativepain interventions and medications.

['Point of no return' in diabetic neuropathies: a dangerous delusion]

Polyneuropathy in patients with diabetes mellitus is manifested by a lesion of peripheral sensory, motor and autonomic nervous system. Different severity of damage of sensory, motor and autonomic fibers in typical and atypical forms of diabetic polyneuropathy, requires a differentiated approach to therapy, but not the rejection of its implementation. In an interdisciplinary consensus, consultations are held with physicians from different regions of the Russian Federation, and modern methods of diagnosing and assessing the severity of diabetic polyneuropathies, which determine the algorithm for treating patients, are discussed.

Intravenous infusion of lidocaine enhances the efficacy of conventional treatment of postherpetic neuralgia

BACKGROUND

Postherpetic neuralgia (PHN) is one kind of severe neuropathic pain which currently cannot be effectively cured. Recent researches suggest that intravenous infusion of lidocaine has a therapeutic effect on neuropathic pain such as PHN; however, the optimal dose and frequency of lidocaine infusion and the effectiveness and safety of this treatment in PHN patients still needs more clinical research. The aim of this study was to evaluate the therapeutic effects of daily intravenous lidocaine infusion on the outcome of the routine treatment of PHN.

METHODS

Sixty PHN patients were randomly divided into two groups: 1) control group (Control), treated with conventional therapies, such as antiepileptic pills, analgesics, neurotrophic medicines, paravertebral spinal nerve block and physiotherapy; 2) lidocaine group (Lido) received daily infusion of lidocaine (4 mg/kg) besides the conventional treatments. If the pain is not controlled sufficiently, additional tramadol is given and the average consumption of tramadol is calculated. Pain intensity was assessed before and after each infusion, and the number of breakthrough pain in the last 24 hrs were recorded. The incidence of adverse reactions related to intravenous lidocaine infusion was recorded.

RESULTS

For five consecutive days, numeric rating scale (NRS) scores were significantly decreased after 1 hr of intravenous infusion of lidocaine. Compared with Control, the NRS scores and the frequency of breakthrough pain in the Lido were significantly reduced. In addition, the extra tramadol consumption in the Lido was significantly lower than that in the Control, and the average hospital stay of patients in Lido was decreased. However, anxiety and depression scores showed no difference between Lido and Control.

CONCLUSION

Daily intravenous lidocaine (4 mg/kg for 5 days) enhanced the outcome of PHN treatment, reduced the amount of analgesic medicine and shortened the length of hospital stay with no obvious adverse side effects.

Tertiary Care Clinical Experience with Intravenous Lidocaine Infusions for the Treatment of Chronic Pain

Objective

To evaluate the safety of and long-term pain relief due to intravenous lidocaine infusion for the treatment of chronic pain in a tertiary pain management clinic.

Design

Retrospective chart review.

Methods

Medical records were reviewed from 233 adult chronic pain patients who underwent one to three lidocaine infusions. The initial lidocaine challenge consisted of 1,000 mg/h administered intravenously for up to 30 minutes until infusion was complete, full pain resolution, the patient requested to stop, side effects (SEs) became intolerable, and/or if there were any safety concerns. Subsequent infusions were tailored to patient response. Data reviewed included pain diagnosis, lidocaine dose, SEs, and duration of pain relief documented at a follow-up visit.

Results

Patients primarily had neuropathic pain (80%), were 94% white, 58% were female, and there was an average pain duration of 7.9 years. SEs were usually mild and transient, including perioral tingling, dizziness, tinnitus, and nausea/vomiting, and they were uncommon after the initial infusion. Overall, 41% of patients showed long-lasting pain relief, with positive response to the initial infusion associated with receiving and benefitting from subsequent infusions. Benefit by pain diagnoses varied from 32% to 58%.

Conclusions

Our retrospective study in a heterogeneous population with chronic pain suggests that intravenous lidocaine is a safe treatment. Data also suggest long-term pain relief in a significant proportion of patients. Additional study is important in order to delineate patient selection, determine optimal dosing and treatment frequency, assess pain reduction and duration, and treatment cost-effectiveness.

Intravenous lidocaine in the management of chronic peripheral neuropathic pain: a randomized-controlled trial

PURPOSE

Neuropathic pain, resulting from injury to the peripheral or central nervous system, is due to upregulation of aberrant sodium channels with neuronal hyperexcitability. Lidocaine blocks these channels and several studies show that intravenous (IV) lidocaine infusion provides significant relief in patients with chronic peripheral neuropathic pain in the short term (for up to six hours). Our objective was to determine if IV lidocaine provides significant pain relief and overall improvement in quality of life in the longer term (for up to four weeks).

METHODS

This single site randomized double-blind, crossover trial compared IV lidocaine infusion (5 mg·kg^-1) with active placebo infusion containing diphenhydramine (50 mg) in patients with chronic neuropathic pain of peripheral nerve origin of at least six months duration. The primary outcome was average pain intensity reduction from IV lidocaine relative to placebo at four weeks post-infusion. Secondary outcome measures included parameters of physical function, mood, and overall quality of life.

RESULTS

We enrolled 34 subjects in this trial-mostly with painful diabetic neuropathy and post-herpetic neuralgia. There were no significant differences between IV lidocaine and placebo infusions at any time point involving any of the outcome measures. Mean (standard deviation) pain intensity at week 4 for the placebo and lidocaine groups were not different [6.58 (1.97) vs 6.78 (1.56), respectively; between-group difference, 0.17; 95% confidence interval, - 0.50 to 0.84].

CONCLUSION

We found no significant long-term analgesic or quality of life benefit from IV lidocaine relative to control infusion for chronic peripheral neuropathic pain.

TRIAL REGISTRATION

clinicaltrials.gov (NCT01669967); registered 22 June, 2012.

Beyond Opioids for Pain Management in Adult Critically Ill Patients

Critically ill patients commonly experience pain, and the provision of analgesia is an essential component of intensive care unit (ICU) care. Opioids are the mainstay of pain management in the ICU but are limited by their adverse effects, risk of addiction and abuse, and recent drug shortages of injectable formulations. A multimodal analgesia approach, utilizing nonopioid analgesics as adjuncts to opioid therapy, is recommended since they may modulate the pain response and reduce opioid requirements by acting on multiple pain mediators. Nonopioid analgesics discussed in detail in this article are acetaminophen, α-2 receptor agonists, gabapentinoids, ketamine, lidocaine, and nonsteroidal anti-inflammatory drugs. This literature review describes the clinical pharmacology, supportive ICU and relevant non-ICU data, and practical considerations associated with the administration of nonopioid analgesics in critically ill adult patients.