Perioperative lidocaine infusions for the prevention of chronic postsurgical pain: a systematic review and meta-analysis of efficacy and safety

Prevention of persistent pain with lidocaine infusions in breast cancer surgery (PLAN): study protocol for a multicenter randomized controlled trial

BACKGROUND

Persistent pain is a common yet debilitating complication after breast cancer surgery. Given the pervasive effects of this pain disorder on the patient and healthcare system, post-mastectomy pain syndrome (PMPS) is becoming a larger population health problem, especially as the prognosis and survivorship of breast cancer increases. Interventions that prevent persistent pain after breast surgery are needed to improve the quality of life of breast cancer survivors. An intraoperative intravenous lidocaine infusion has emerged as a potential intervention to decrease the incidence of PMPS. We aim to determine the definitive effects of this intervention in patients undergoing breast cancer surgery.

METHODS

PLAN will be a multicenter, parallel-group, blinded, 1:1 randomized, placebo-controlled trial of 1,602 patients undergoing breast cancer surgery. Adult patients scheduled for a lumpectomy or mastectomy will be randomized to receive an intravenous 2% lidocaine bolus of 1.5 mg/kg with induction of anesthesia, followed by a 2.0 mg/kg/h infusion until the end of surgery, or placebo solution (normal saline) at the same volume. The primary outcome will be the incidence of persistent pain at 3 months. Secondary outcomes include the incidence of pain and opioid consumption at 1 h, 1-3 days, and 12 months after surgery, as well as emotional, physical, and functional parameters, and cost-effectiveness.

DISCUSSION

This trial aims to provide definitive evidence on an intervention that could potentially prevent persistent pain after breast cancer surgery. If this trial is successful, lidocaine infusion would be integrated as standard of care in breast cancer management. This inexpensive, widely available, and easily administered intervention has the potential to reduce pain and suffering in an already afflicted patient population, decrease the substantial costs of chronic pain management, potentially decrease opioid use, and improve the quality of life in patients.

TRIAL REGISTRATION

This trial has been registered on clinicaltrials.gov (NCT04874038, Dr. James Khan. Date of registration: May 5, 2021).

Mechanisms and Preventative Strategies for Persistent Pain following Knee and Hip Joint Replacement Surgery: A Narrative Review

Chronic postsurgical pain (CPSP) following total knee arthroplasty (TKA) and total hip arthroplasty (THA) is a prevalent complication of joint replacement surgery which has the potential to decrease patient satisfaction, increase financial burden, and lead to long-term disability. The identification of risk factors for CPSP following TKA and THA is challenging but essential for targeted preventative therapy. Recent meta-analyses and individual studies highlight associations between elevated state anxiety, depression scores, preoperative pain, diabetes, sleep disturbances, and various other factors with an increased risk of CPSP, with differences observed in prevalence between TKA and THA. While the etiology of CPSP is not fully understood, several factors such as chronic inflammation and preoperative central sensitization have been identified. Other potential mechanisms include genetic factors (e.g., catechol-O-methyltransferase (COMT) and potassium inwardly rectifying channel subfamily J member 6 (KCNJ6) genes), lipid markers, and psychological risk factors (anxiety and depression). With regards to therapeutics and prevention, multimodal pharmacological analgesia, emphasizing nonopioid analgesics like acetaminophen and non-steroidal anti-inflammatory drugs (NSAIDs), has gained prominence over epidural analgesia. Nerve blocks and local infiltrative anesthesia have shown mixed results in preventing CPSP. Ketamine, an N-methyl-D-aspartate (NMDA)-receptor antagonist, exhibits antihyperalgesic properties, but its efficacy in reducing CPSP is inconclusive. Lidocaine, an amide-type local anesthetic, shows tentative positive effects on CPSP. Selective serotonin reuptake inhibitors (SSRIs) and serotonin norepinephrine reuptake inhibitors (SNRIs) have mixed results, while gabapentinoids, like gabapentin and pregabalin, present hopeful data but require further research, especially in the context of TKA and THA, to justify their use for CPSP prevention.

Serum lidocaine (lignocaine) concentrations during prolonged perioperative infusion in patients undergoing breast cancer surgery: A secondary analysis of a randomised controlled trial

Perioperative lidocaine (lignocaine) infusions are being employed with increasing frequency. The determinants of systemic lidocaine concentrations during prolonged administration are unclear. In the Long-term Outcomes after Lidocaine Infusions for PostOperative Pain (LOLIPOP) pilot trial, the impact of infusion duration and body size metrics on serum lidocaine concentrations was examined with regression models in 48 women undergoing breast cancer surgery. Lidocaine was delivered as an intravenous bolus (1.5 mg/kg) and infusion (2 mg/kg per h) intraoperatively, followed by a 12-h subcutaneous infusion (1.33 mg/kg per h) postoperatively. Dosing was based on total body weight. Wound infiltration with other long-acting local anaesthetics was permitted. Protein binding and pharmacogenomic data were also collected. Lidocaine concentrations (median (interquartile range) (range)) during prolonged administration were in the safe and potentially therapeutic range: post-anaesthesia care unit 2.16 (1.73-2.82) (1.12-6.06) µg/ml; ward 1.41 (1.22-1.75) (0.64-2.81) µg/ml. Concentrations increased non-linearly during the early intravenous phase of administration (mean rise 1.21 µg/ml per hour of infusion, P = 0.007) but reached a pseudo steady-state during the later subcutaneous phase. Higher dose rates received per kilogram of lean (P = 0.004), adjusted (P = 0.006) and ideal body weight (P = 0.009) were associated with higher steady-state concentrations. The lidocaine free fraction was unaffected by the presence of ropivacaine, and phenotypes linked to slow metabolism were infrequent. Serum lidocaine concentrations reached a pseudo steady-state during a 12-h postoperative infusion. Greater precision in steady-state concentrations can be achieved by dosing on lean body weight versus adjusted or ideal body weight (equivalent lean body weight doses: intravenous bolus 2.5 mg/kg; intravenous infusion 3.33 mg/kg per h; subcutaneous infusion 2.22 mg/kg per h.

Impact of the COVID-19 pandemic on dispensing medicines in the community pharmacy

BACKGROUND

The world has faced an unprecedented challenge since COVID-19 emerged as a pandemic, which has led to quarantine and disruptions in drug services. During the pandemic, drug use habits and availability changed, causing a shift in behaviors and, in turn, medicine misuse. In Iraq, this is a major problem because many medicines can be easily obtained.

OBJECTIVE

The study aims to describe the pattern of dispensing medications during the pandemic and to evaluate the biochemical and pathological consequences.

METHOD

The analytical, observational, cross-sectional study was performed via a compiled questionnaire for 400 random pharmacists, and the analysis and interpretation of the biochemical changes and medical reports.

RESULTS

Results revealed that dispensing of medications since the COVID-19 outbreak has increased by 74%, and the demand for medicines seems higher than required in comparison to the periods before the pandemic, while 60% of the dispensed medicines were taken just in case needed. In addition, the availability of medicines decreased by 61%, and the dispensing of common medicines increased due to the belief in their prophylactic action. Several biochemical abnormalities and pathological consequences were recorded due to the irrational use of medicines, and the highest percentage (12%) was seen in hepatic and liver enzymatic dysfunction and 8% for the endocrine and hormonal abnormalities.

CONCLUSION

It can be concluded that most of the dispensed medicines were not used on a therapeutic or scientific basis during the pandemic.

Perioperative intravenous lidocaine use in children

Perioperative pain management impacts patient morbidity, quality of life, and hospitalization cost. In children, it impacts not only the child, but the whole family. Adjuncts for improved perioperative analgesia continue to be sought to minimize adverse side effects associated with opioids and for those in whom regional or neuraxial anesthesia is not suitable. The use of ketamine and alpha agonists may be useful in these settings but have noted adverse effects including hallucinations, hemodynamic instability, and excessive sedation. One alternative is intravenous lidocaine. Despite its off-label use, intravenous lidocaine has demonstrated anti-neuropathic, anti-hyperalgesic, and anti-inflammatory actions and is an emerging technique. Multiple studies in adults have demonstrated beneficial effects of perioperative intravenous lidocaine including improved perioperative analgesia with reduced postoperative opioid use, improved gastrointestinal function, earlier mobilization, and reduction in hospital length of stay. Despite the limited pediatric literature, some of these findings have been replicated. Large-scale trials providing evidence for the pediatric pharmacokinetics and high-quality safety data with respect to intravenous lidocaine are still however lacking. To date, dose ranges studied in the pediatric population have not been associated with serious side effects and current data suggests perioperative intravenous lidocaine in a subgroup of pediatric surgical patients seems well-tolerated and beneficial.

Effect of perioperative lignocaine infusion on postoperative pain relief for laparoscopic intraperitoneal onlay mesh repair: A randomized controlled study

INTRODUCTION

The focus on enhanced recovery after surgery (ERAS) and opioid-free anesthesia has renewed interest in use of lignocaine. We evaluated postoperative pain relief following intravenous (IV) lignocaine administration in patients undergoing laparoscopic intraperitoneal onlay mesh repair (IPOM).

METHODS

Seventy patients were randomized into two groups. Group L patients were administered IV lignocaine infusion (1.5 mg/kg) at induction of anesthesia followed by infusion (1.5 mg/kg/h), until 1 hour in the post-anesthesia care unit (PACU). Group P patients received equal volumes of normal saline IV infusion. We recorded hemodynamics, perioperative analgesic consumption, postoperative visual analog scores (VAS), incidence of postoperative nausea and vomiting (PONV), bowel function, patient satisfaction and length of hospital stay (LOS).

RESULTS

The hemodynamics in both groups were maintained. Group L had lower VAS scores as compared to Group P (P < .05). Intraoperative fentanyl consumption in Group L was significantly less than Group P (P = .029). Group L patients scored lower on the Likert scale in comparison to the patients of Group P at 0 hour (P = .013). Recovery of bowel function as assessed by time to pass first flatus was significantly shortened by IV lignocaine (P = .001). The perioperative administration of IV lignocaine resulted in decreased postoperative analgesic requirement and greater patient satisfaction scores.

CONCLUSIONS

Perioperative IV lignocaine infusion provided good pain relief, hemodynamic stability and decreased perioperative analgesic consumption. PONV incidence decreased along with an early return of bowel function, reduced LOS and improved patient satisfaction in patients undergoing laparoscopic IPOM surgery.

Effect of intravenous lidocaine on pain after head and neck cancer surgery (ELICO trial): A randomised controlled trial

BACKGROUND

Treatment of postoperative pain after ear, nose and throat (ENT) cancer surgery is mainly morphine administration. Additional systemic lidocaine has shown promising results in some surgical procedures.

OBJECTIVE

The main objective was to evaluate morphine consumption in the first 48 postoperative hours after intra-operative lidocaine infusion during major ENT cancer surgery.

DESIGN

A randomised, double-blind, placebo-controlled trial.

SETTING

Bicentric study including a university hospital and a major cancer centre, conducted from December 2016 to December 2019.

PATIENTS

A total of 144 patients undergoing major ENT cancer surgery were included.

INTERVENTION

The patients were randomly assigned to receive intravenous lidocaine or placebo during surgery and in the recovery room.

MAIN OUTCOME MEASURES

Endpoints were postoperative morphine consumption in the first 24 and 48 h postoperatively, intra-operative remifentanil consumption, adverse events occurrence and assessment 3 to 6 months after surgery with the McGill pain questionnaire.

RESULTS

A total of 118 patients were included (lidocaine n  = 57; placebo n  = 61, 26 patients were excluded). There was no significant difference in morphine consumption during the first 48 postoperative hours in the lidocaine group compared with the placebo group with a median [IQR] of 0.60 [0.30 to 1.03] mg kg -1 vs. 0.57 [0.37 to 0.96] mg kg -1 , total dose 44 [21 to 73.3] mg vs. 38 [23.3 to 56.5] mg, P  = 0.92.There was no significant difference between the two groups in any of the other endpoints, including at follow up 3 to 6 months after surgery.

CONCLUSION

Intravenous lidocaine in ENT cancer surgery did not show any additional analgesic or morphine-sparing effect 48 h after surgery. Three to six months after surgery, there was no significant difference in pain scores or consumption of analgesics. Patients treated pre-operatively with opioids were not evaluated in the study.

TRIAL REGISTRATION

Clinicaltrials.gov identifier: NCT02894710 and EUDRACT number 2015-005799-90.

Pain Management of Acute and Chronic Postoperative Pain

Inadequate management of acute postoperative pain is associated with effects related to both physiological and psychological function. Postoperative pain increases the risk of perioperative complications, so postoperative pain should be prevented. Postoperative pain management by sufficient analgesia is important while considering the use of various kinds of analgesics. Insufficient management of postoperative pain may lead to chronic postsurgical pain (CPSP). It is suggested that CPSP is dependent not only upon biological factors but also upon psychological factors, including the type of surgery, age, physical health, mental health, and preoperative pain. As CPSP is a severe complication that may prolong hospitalization and interferes with activities of daily living (ADL) and quality of life (QoL), its prevention of development is paramount. Therefore, in order to prevent the onset of CPSP, it is necessary to craft analgesic management to prevent CPSP during the perioperative period.

Quality of meta-analyses of non-opioid, pharmacological, perioperative interventions for chronic postsurgical pain: a systematic review

Background

In an attempt to aggregate observations from clinical trials, several meta-analyses have been published examining the effectiveness of systemic, non-opioid, pharmacological interventions to reduce the incidence of chronic postsurgical pain.

Objective

To inform the design and reporting of future studies, the purpose of our study was to examine the quality of these meta-analyses.

Evidence review

We conducted an electronic literature search in Embase, MEDLINE, and the Cochrane Database of Systematic Reviews. Published meta-analyses, from the years 2010 to 2020, examining the effect of perioperative, systemic, non-opioid pharmacological treatments on the incidence of chronic postsurgical pain in adult patients were identified. Data extraction focused on methodological details. Meta-analysis quality was assessed using the A Measurement Tool to Assess Systematic Reviews 2 (AMSTAR 2) critical appraisal tool.

Findings

Our search yielded 17 published studies conducting 58 meta-analyses for gabapentinoids (gabapentin and pregabalin), ketamine, lidocaine, non-steroidal anti-inflammatory drugs, and mexiletine. According to AMSTAR 2, 88.2% of studies (or 15/17) were low or critically low in quality. The most common critical element missing was an analysis of publication bias. Trends indicated an improvement in quality over time and association with journal impact factor.

Conclusions

With few individual trials adequately powered to detect treatment effects, meta-analyses play a crucial role in informing the perioperative management of chronic postsurgical pain. In light of this inherent value and despite a number of attempts, high-quality meta-analyses are still needed.

PROSPERO registration number

CRD42021230941.

Perioperative Dexmedetomidine or Lidocaine Infusion for the Prevention of Chronic Postoperative and Neuropathic Pain After Gynecological Surgery: A Randomized, Placebo-Controlled, Double-Blind Study

Introduction

The transition of acute to chronic postoperative pain (CPP) remains a significant burden to the rehabilitation of patients. The research for adjuvants to prevent CPP continues; among others, dexmedetomidine and lidocaine seem promising agents.

Methods

This is a long-term follow-up of a randomized, placebo-controlled, double-blind study on women who underwent open abdominal gynecological surgery and received dexmedetomidine or lidocaine or placebo infusion perioperatively (n = 81). The effect of these adjuvants on the development of CPP and neuropathic pain was assessed during a 12-month follow-up. Eighty-one (81) women ASA I–II, aged between 30 and 70 years, were randomly assigned to receive either dexmedetomidine (DEX group) or lidocaine (LIDO group) or placebo (CONTROL group) perioperatively. Before anesthesia induction, all patients received a loading intravenous dose of either 0.6 μg/kg dexmedetomidine or 1.5 mg/kg lidocaine or placebo, followed by 0.6 μg/kg/h dexmedetomidine or 1.5 mg/kg/h lidocaine or placebo until last suture. Patients were followed up to obtain the long-term outcomes at 3, 6, and 12 months. At these time-points, pain intensity was assessed with the Numerical Rating Scale, (NRS: 0–10) and the development of neuropathic elements with the Douleur Neuropathique 4 (DN4) score. Prognostic parameters that could affect chronic pain and its components were also identified.

Results

Data from 74 women were analyzed. Dexmedetomidine significantly reduced NRS scores comparing to placebo at 3 months (p = 0.018), while at 6 months, lidocaine was found superior to placebo (p = 0.02), but not to dexmedetomidine, in preventing neuropathic pain (DN4 < 4). Regarding secondary endpoints, higher NRS cough scores at 48 h were associated with statistically significant NRS and DN4 scores at 3, 6, and 12 months (p < 0.02). At 6 months, a statistically significant correlation was also found between higher NRS values and older age (p = 0.020).

Conclusions

Dexmedetomidine was superior to placebo regarding the duration and severity of CPP, while lidocaine exhibited a protective effect against neuropathic elements of CPP.

Trial registration

ClinicalTrials.gov identifier, NCT03363425.

Supplementary Information

The online version contains supplementary material available at 10.1007/s40122-022-00361-5.

Preventing Persistent Postsurgical Pain: A Systematic Review and Component Network Meta-analysis

BACKGROUND AND OBJECTIVES

Evidence for perioperative methods to prevent persistent postsurgical pain (PPP) is uncertain, in part because few treatments have been directly compared. Here we have used component network meta-analysis (cNMA) to incorporate both direct and indirect evidence in the evaluation of the efficacy and tolerability of pharmacological and neural block treatments.

DATABASES AND DATA TREATMENT

We searched the Cochrane Central Registry of Controlled Trials, Embase, MEDLINE, ClinicalTrials.gov, and the World Health Organization International Clinical Trials Registry up to January 2021, for randomized, double-masked, controlled trials that reported the prevalence of PPP. We assessed trial quality with the Cochrane risk of bias tool (RoB 2.0). We analyzed the results with frequentist cNMA models. The primary outcome was the relative risk (RR) of PPP. We assessed efficacy in relation to a clinically important effect size of RR = 0.9, which is a 10% improvement with treatment.

RESULTS

The analysis included 107 trials (13,553 participants) of 13 treatments. The effects of complex interventions were the multiplicative effects of their components. Compared with placebo, serotonin-norepinephrine reuptake inhibitors (SNRIs), neural block alone, or in combination with NMDA receptor blockers or gabapentanoids were effective. Treatments with benefit in the immediate post-operative period predicted a reduced risk of PPP.

CONCLUSIONS

Several treatments and treatment combinations effectively reduce PPP prevalence. Pain outcomes in the immediate postoperative period are an important mediator of PPP. Multimodal interventions can be analyzed using cNMA.

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.

Efficacy of intraoperative intravenous lidocaine for postoperative analgesia following bariatric surgery: a meta-analysis of randomized controlled studies

BACKGROUND

The impact of intravenous lidocaine in adults undergoing laparoscopic bariatric surgeries (LBS) remains unclear.

OBJECTIVES

This study aimed at investigating the effect of intravenous lidocaine on postoperative opioid consumption and recovery following LBS.

SETTING

Meta-analysis.

METHODS

We searched databases including MEDLINE, Embase, Google Scholar, and the Cochrane Library for randomized controlled trials that evaluated the use of intravenous lidocaine compared to placebo only prior to May 2021. The primary outcome was 24-hour postoperative opioid consumption, while secondary outcomes included pain score, quality of recovery (QOR)-40 score, length of hospital stay (LOS), and postoperative nausea/vomiting (PONV).

RESULTS

Seven trials (496 participants) were included. Intraoperative intravenous lidocaine significantly reduced 24-hour equivalent morphine consumption (mean difference [MD]: -11.97 mg; 95% confidence interval [CI]: -23.12 to -.83), pain score at 1 to 3 hours (MD: -.77; 95% CI: -1.5 to -.04), and LOS (MD: -8.93 hr; 95% CI: -13.41 to -4.44) without positive impact on 24-hour pain score and PONV. There was also an increase in time to first opioid requirement (MD: 20.23 min; 95% CI: 11.76-28.7) and QOR-40 score (MD: 24.38; 95% CI: 5.57-43.18). However, sensitivity analysis demonstrated evidence supporting the beneficial effect of lidocaine only for time to first opioid requirement and QOR-40. The associations of intraoperative intravenous lidocaine with reductions in morphine consumption, pain score at 1 to 3 hours, and LOS after LBS were also weak.

CONCLUSION

Intraoperative intravenous lidocaine during LBS prolonged time to first opioid requirement and improved quality of recovery postoperatively without 24-hour pain or nausea/vomiting benefits. Due to the small number of trials, larger studies are warranted to verify our findings.

Molecular mechanisms of lidocaine

Lidocaine is an amide-class local anesthetic used clinically to inhibit pain sensations. Systemic administration of lidocaine has antinociceptive, antiarrhythmic, anti-inflammatory, and antithrombotic effects. Lidocaine exerts these effects under both acute and chronic pain conditions and acute respiratory distress syndrome through mechanisms that can be independent of its primary mechanism of action, sodium channel inhibition. Here we review the pathophysiological underpinnings of lidocaine's role as an anti-nociceptive, anti-inflammatory mediated by toll-like receptor (TLR) and nuclear factor kappa-β (NF-kβ) signalling pathways and downstream cytokine effectors high mobility group box 1 (HMGB1) and tumour necrosis factor-α (TNF-α).

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.

Pharmacotherapy for the Prevention of Chronic Pain after Surgery in Adults: An Updated Systematic Review and Meta-analysis

BACKGROUND

Chronic postsurgical pain can severely impair patient health and quality of life. This systematic review update evaluated the effectiveness of systemic drugs to prevent chronic postsurgical pain.

METHODS

The authors included double-blind, placebo-controlled, randomized controlled trials including adults that evaluated perioperative systemic drugs. Studies that evaluated same drug(s) administered similarly were pooled. The primary outcome was the proportion reporting any pain at 3 or more months postsurgery.

RESULTS

The authors identified 70 new studies and 40 from 2013. Most evaluated ketamine, pregabalin, gabapentin, IV lidocaine, nonsteroidal anti-inflammatory drugs, and corticosteroids. Some meta-analyses showed statistically significant-but of unclear clinical relevance-reductions in chronic postsurgical pain prevalence after treatment with pregabalin, IV lidocaine, and nonsteroidal anti-inflammatory drugs. Meta-analyses with more than three studies and more than 500 participants showed no effect of ketamine on prevalence of any pain at 6 months when administered for 24 h or less (risk ratio, 0.62 [95% CI, 0.36 to 1.07]; prevalence, 0 to 88% ketamine; 0 to 94% placebo) or more than 24 h (risk ratio, 0.91 [95% CI, 0.74 to 1.12]; 6 to 71% ketamine; 5 to 78% placebo), no effect of pregabalin on prevalence of any pain at 3 months (risk ratio, 0.88 [95% CI, 0.70 to 1.10]; 4 to 88% pregabalin; 3 to 80% placebo) or 6 months (risk ratio, 0.78 [95% CI, 0.47 to 1.28]; 6 to 68% pregabalin; 4 to 69% placebo) when administered more than 24 h, and an effect of pregabalin on prevalence of moderate/severe pain at 3 months when administered more than 24 h (risk ratio, 0.47 [95% CI, 0.33 to 0.68]; 0 to 20% pregabalin; 4 to 34% placebo). However, the results should be interpreted with caution given small study sizes, variable surgical types, dosages, timing and method of outcome measurements in relation to the acute pain trajectory in question, and preoperative pain status.

CONCLUSIONS

Despite agreement that chronic postsurgical pain is an important topic, extremely little progress has been made since 2013, likely due to study designs being insufficient to address the complexities of this multifactorial problem.

EDITOR’S PERSPECTIVE

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.

The effect of systemic lidocaine on post-operative opioid consumption in ambulatory surgical patients: a meta-analysis of randomized controlled trials

Background

Ambulatory surgical procedures continue to grow in relevance to perioperative medicine. Clinical studies have examined the use of systemic lidocaine as a component of multimodal analgesia in various surgeries with mixed results. A quantitative review of the opioid-sparing effects of systemic lidocaine in ambulatory surgery has not been investigated. The primary objective of this study was to systematically review the effectiveness of systemic lidocaine on postoperative analgesic outcomes in patients undergoing ambulatory surgery.

Methods

We performed a quantitative systematic review of randomized controlled trials in electronic databases (Cochrane Library, Embase, PubMed, and Google Scholar) from their inception through February 2019. Included trials investigated the effects of intraoperative systemic lidocaine on postoperative analgesic outcomes, time to hospital discharge, and adverse events. Methodological quality was evaluated using Cochrane Collaboration’s tool and the level of evidence was assessed using GRADE criteria. Data was combined in a meta-analysis using random-effects models.

Results

Five trials evaluating 297 patients were included in the analysis. The pooled effect of systemic lidocaine on postoperative opioid consumption at post-anesthesia care unit revealed a significant effect, weighted mean difference (95% CI) of − 4.23 (− 7.3 to 1.2, P = 0.007), and, at 24 h, weighted mean difference (95% CI) of − 1.91 (− 3.80 to − 0.03, P = 0.04) mg intravenous morphine equivalents. Postoperative pain control during both time intervals, postoperative nausea and vomiting reported at post anesthesia care unit, and time to hospital discharge were not different between groups. The incidence rate of self-limiting adverse events of the included studies is 0.007 (2/297).

Conclusion

Our results suggest that intraoperative systemic lidocaine as treatment for postoperative pain has a moderate opioid-sparing effect in post anesthesia care unit with limited effect at 24 h after ambulatory surgery. Moreover, the opioid-sparing effect did not impact the analgesia or the presence of nausea and vomiting immediately or 24 h after surgery. Clinical trials with larger sample sizes are necessary to further confirm the short-term analgesic benefit of systemic lidocaine following ambulatory surgery.

Trial registration

PROSPERO (CRD42019142229)

Supplementary Information

The online version contains supplementary material available at 10.1186/s13741-021-00181-9.

A pilot multicentre randomised controlled trial of lidocaine infusion in women undergoing breast cancer surgery

Chronic postoperative pain is common after breast cancer surgery. Peri-operative lidocaine infusion may prevent the development of chronic postoperative pain, but a large-scale trial is required to test this hypothesis. It is unclear whether a pragmatic, multicentre trial design that is consistent with expert guidance, addresses the limitations of previous studies, and overcomes existing translational barriers is safe, effective and feasible. We conducted a double-blind, randomised controlled pilot study in 150 patients undergoing breast cancer surgery across three hospitals in Western Australia. Patients received lidocaine, or equivalent volumes of saline, as an intravenous bolus (1.5 mg.kg^-1 ) and infusion (2 mg.kg^-1 .h^-1 ) intra-operatively, and a subcutaneous infusion (1.33 mg.kg^-1 .h^-1 ) postoperatively for up to 12 h on a standard surgical ward, with novel safety monitoring tools in place. The co-primary outcomes were: in-hospital safety events; serum levels of lidocaine during intravenous and subcutaneous infusion; and annualised enrolment rates per site with long-term data capture. In-hospital safety events were rare, and similar in the placebo and lidocaine arms (3% vs. 1%). Median (IQR [range]) serum lidocaine levels during intravenous (2.16 (1.74-2.83 [1.12-6.06]) µg.ml^-1 , n = 41) and subcutaneous (1.52 (1.28-1.83 [0.64-2.85]) µg.ml^-1 , n = 48) infusion were comparable with previous trials reporting improved pain outcomes. Annualised enrolment approximated 50 patients per site per year, with high levels of protocol adherence and ≥ 99% capture of outcomes at 3 and 6 months. The adjusted odds ratio (95%CI) for postoperative pain at 6 months in the lidocaine arm was 0.790 (0.370-1.684). We conclude that this trial, as designed, is safe, effective and feasible in patients undergoing breast cancer surgery, and a larger-scale trial is planned.

[Prediction and prevention of chronic postoperative pain]

Chronic postoperative pain has been identified as a major medical and socioeconomic problem. A prevention of the chronification processes is potentially possible and preventive treatment could start early (e.g. preoperatively). So far, however, evidence for the effectiveness of preventive strategies is basically low. Important reasons for this dilemma are the lack of appropriate risk assessment as well as effective and mechanism-based preventive (procedure-sepcific) strategies for the chronification process, a lack of stratification of treatment approaches and a so far barely investigated combination of various treatment approaches. In this review article recent findings on the appropriate identification of patients at risk for developing postoperative chronic pain are presented, predictive models for the valid estimation of the individual risk of patients are assessed and studies on pharmaceutical and regional analgesia techniques influencing the pain chronification process are discussed. As a chronification process is, however, extremely complex and dynamic and also necessitates adaptation of the prevention during the course of the process, only combinations of treatment, interdisciplinary and if necessary even longer term approaches might be successful. Future studies are needed to address with which preventive treatment strategies and in which patients chronic pain after surgery can effectively be prevented.

The role of regional anaesthesia and multimodal analgesia in the prevention of chronic postoperative pain: a narrative review

Effective prevention of chronic postoperative pain is an important clinical goal, informed by a growing body of studies. Peri-operative regional anaesthesia remains one of the most important tools in the multimodal analgesic toolbox, blocking injury-induced activation and sensitisation of both the peripheral and central nervous system. We review the definition and taxonomy of chronic postoperative pain, its mechanistic basis and the most recent evidence for the preventative potential of multimodal analgesia, with a special focus on regional anaesthesia. While regional anaesthesia targets several important aspects of the mechanistic pathway leading to chronic postoperative pain, evidence for its efficacy is still mixed, possibly owing to the heterogeneity of risk profiles within the surgical patient, but also to variation in techniques and medications reported in the literature.

Postoperative Pain Management in Pediatric Spinal Fusion Surgery for Idiopathic Scoliosis

This article reviews and summarizes current evidence and knowledge gaps regarding postoperative analgesia after pediatric posterior spine fusion for adolescent idiopathic scoliosis, a common procedure that results in severe acute postoperative pain. Inadequate analgesia may delay recovery, cause patient dissatisfaction, and increase chronic pain risk. Despite significant adverse effects, opioids are the analgesic mainstay after scoliosis surgery. However, growing emphasis on opioid minimization and enhanced recovery has increased adoption of multimodal analgesia (MMA) regimens. While opioid adverse effects remain a concern, MMA protocols must also consider risks and benefits of adjunct medications. We discuss use of opioids via different administration routes and elaborate on the effect of MMA components on opioid/pain and recovery outcomes including upcoming regional analgesia. We also discuss risk for prolonged opioid use after surgery and chronic post-surgical pain risk in this population. Evidence supports use of neuraxial opioids at safe doses, low-dose ketorolac, and methadone for postoperative analgesia. There may be a role for low-dose ketamine in those who are opioid-tolerant or have chronic pain, but the evidence for preoperative gabapentinoids and intravenous lidocaine is currently insufficient. There is a need for further studies to evaluate pediatric-specific optimal MMA dosing regimens after scoliosis surgery. Questions remain regarding how best to prevent acute opioid tolerance, opioid-induced hyperalgesia, and chronic postsurgical pain. We anticipate that this timely update will enable clinicians to develop efficient pain regimens and provide impetus for future research to optimize recovery outcomes after spine fusion.

Pain Pathways and Nervous System Plasticity: Learning and Memory in Pain

Objective This article reviews the structural and functional changes in pain chronification and explores the association between memory and the development of chronic pain. Methods PubMed was searched using the terms "chronic pain," "central sensitization," "learning," "memory," "long-term potentiation," "long-term depression," and "pain memory." Relevant findings were synthesized into a narrative of the processes affecting pain chronification. Results Pain pathways represent a complex sensory system with cognitive, emotional, and behavioral influences. Anatomically, the hippocampus, amygdala, and anterior cortex-central to the encoding and consolidation of memory-are also implicated in experiential aspects of pain. Common neurotransmitters and similar mechanisms of neural plasticity (eg, central sensitization, long-term potentiation) suggest a mechanistic overlap between chronic pain and memory. These anatomic and mechanistic correlates indicate that chronic pain and memory intimately interact on several levels. Longitudinal imaging studies suggest that spatiotemporal reorganization of brain activity accompanies the transition to chronic pain, during which the representation of pain gradually shifts from sensory to emotional and limbic structures. Conclusions The chronification of pain can be conceptualized as activity-induced plasticity of the limbic-cortical circuitry resulting in reorganization of the neocortex. The state of the limbic-cortical network determines whether nociceptive signals are transient or chronic by extinguishing pathways or amplifying signals that intensify the emotional component of nociceptive inputs. Thus, chronic pain can be seen as the persistence of the memory of pain and/or the inability to extinguish painful memories. Ideally, pharmacologic, physical, and/or psychological approaches should reverse the reorganization accompanying chronic pain.

Optimizing Perioperative Use of Opioids: A Multimodal Approach

Purpose of Review

The main purpose of this article is to review recent literature regarding multimodal analgesia medications, citing their recommended doses, efficacy, and side effects. The second part of this report will provide a description of drugs in different stages of development which have novel mechanisms with less side effects such as tolerance and addiction.

Recent Findings

Multimodal analgesia is a technique that facilitates perioperative pain management by employing two or more systemic analgesics along with regional anesthesia, when possible. Even though opioids and non-opioid analgesics remain the most common medication used for acute pain management after surgery, they have many undesirable side effects including the potential for misuse. Newer analgesics including peripheral acting opioids, nitric oxide inhibitors, calcitonin gene-related peptide receptor antagonists, interleukin-6 receptor antagonists and gene therapy are under intensive investigation.

Summary

A patient's first exposure to opioids is often in the perioperative setting, a vulnerable time when multimodal therapy can play a large role in decreasing opioid exposure. Additionally, the current shift towards faster recovery times, fewer post-operative complications and improved cost-effectiveness during the perioperative period has made multimodal analgesia a central pillar of Enhanced Recovery After Surgery (ERAS) protocols.

Assessment of the Effect of Perioperative Venous Lidocaine on the Intensity of Pain and IL-6 Concentration After Laparoscopic Gastroplasty

BACKGROUND AND OBJECTIVES

Opioids are associated with sedation and respiratory depression. The primary objective of this study was to assess pain intensity after gastric bypass with lidocaine. The secondary objective was to assess the IL-6 concentration, consumption of morphine, time to morphine request, time to extubation, and side effects.

METHODS

Sixty patients aged 18 to 60 years, with ASA (American Society of Anesthesiologists) scores of 2 or 3, who underwent bariatric surgery were allocated to two groups. Patients in group 1 were administered lidocaine (1.5 mg/kg) 5 min before the induction of anesthesia, and group 2 was administered 0.9% saline solution in an equal volume. Subsequently, lidocaine (2 mg/kg/h) or 0.9% saline was infused during the entire surgical procedure. Anesthesia was performed with fentanyl (5 μg/kg), propofol, rocuronium, and sevoflurane. Postoperative patient-controlled analgesia was provided with morphine. The following were evaluated: pain intensity, IL-6, 24-h consumption of morphine, time to the morphine request, time to extubation, and adverse effects.

RESULTS

The lidocaine group had a lower pain intensity than the saline group for up to 1 h, with no differences between groups in IL-6 and time to extubation. The lidocaine group consumed less morphine within 24 h, had a longer time until the first supplemental morphine request, and had a lower incidence of nausea.

CONCLUSIONS

Lidocaine reduced the intensity of early postoperative pain, incidence of nausea, and consumption of morphine within 24 h and increased time to the first morphine request, without reducing the plasma concentrations of IL-6.

The effect of intraoperative lidocaine infusion on opioid consumption and pain after totally extraperitoneal laparoscopic inguinal hernioplasty: a randomized controlled trial

BACKGROUND

As a component of multimodal analgesia, the administration of systemic lidocaine is a well-known technique. We aimed to evaluate the efficacy of lidocaine infusion on postoperative pain-related outcomes in patients undergoing totally extraperitoneal (TEP) laparoscopies inguinal hernioplasty.

METHODS

In this randomized controlled double-blind study, we recruited 64 patients to receive either lidocaine 2% (intravenous bolus 1.5 mg. kg ^- 1 followed by an infusion of 2 mg. kg^- 1. h^- 1), or an equal volume of normal saline. The infusion was initiated just before the induction of anesthesia and discontinued after tracheal extubation. The primary outcome of the study was postoperative morphine equivalent consumption up to 24 h after surgery. Secondary outcomes included postoperative pain scores, nausea/vomiting (PONV), sedation, quality of recovery (scores based on QoR-40 questionnaire), patient satisfaction, and the incidence of chronic pain.

RESULTS

The median (IQR) cumulative postoperative morphine equivalent consumption in the first 24 h was 0 (0-1) mg in the lidocaine group and 4 [1-8] mg in the saline group (p < 0.001). Postoperative pain intensity at rest and during movement at various time points in the first 24 h were significantly lower in the lidocaine group compared with the saline group (p < 0.05). Fewer patients reported PONV in the lidocaine group than in the saline group (p < 0.05). Median QoR scores at 24 h after surgery were significantly better in the lidocaine group (194 (194-196) than saline group 184 (183-186) (p < 0.001). Patients receiving lidocaine were more satisfied with postoperative analgesia than those receiving saline (p = 0.02). No difference was detected in terms of postoperative sedation and chronic pain after surgery.

CONCLUSIONS

Intraoperative lidocaine infusion for laparoscopic TEP inguinal hernioplasty reduces opioid consumption, pain intensity, PONV and improves the quality of recovery and patient satisfaction.

TRIAL REGISTRATION

ClinicalTrials.gov- NCT02601651. Date of registration: November 10, 2015.

Local Anesthetic Toxicity in the Geriatric Population

This article provides a concise overview of local anesthetic systemic toxicity, its history, mechanisms, risk factors, prevention, clinical presentation, and treatment, with a special emphasis on issues specific to the geriatric population. The authors used MEDLINE, Scopus, and Google Scholar to search for original research articles (human and animal studies), registries data, case reports, review articles, and pertinent online publications using the combinations of the following search terms: local anesthetics, local anesthetic systemic toxicity, intralipid, lipid emulsion, Exparel, ultrasound-guidance, regional anesthesia, lidocaine, bupivacaine, ropivacaine, cocaine, procaine, tetracaine, levobupivacaine, liposomal bupivacaine, lignocaine. Local anesthetic systemic toxicity continues to occur despite the use of putatively less cardiotoxic formulations of local anesthetics and more common use of ultrasound guidance. The elderly appear to be at a disproportionately increased risk for toxicity owing to the presence of relevant comorbidities and decreased muscle mass. Examination of recent case reports involving patients over the age of 65 years demonstrates that inadvertent overdosing is responsible for some cases of local anesthetic systemic toxicity. Elderly patients are at increased risk of local anesthetic systemic toxicity. When considering use of local anesthetics in older patients, special attention should be paid to the presence of systemic disease and muscle wasting. The safety of regional anesthesia and multi-modal analgesia among these at-risk patients will be improved by educating physicians and staff to recognize and manage local anesthetic systemic toxicity.

Post-Cardiotomy Parasternal Nerve Block with Bupivacaine may be Associated with Reduced Post-Operative Opioid Use in Children: A Retrospective Cohort Study

Postoperative pain treatment affects immediate and long-term outcomes in children undergoing cardiac surgery. Opioids, as part of multimodal analgesia, are effective in treating pain, however, they can be disadvantageous due to adverse side effects. Therefore, we assessed whether the local anesthetic bupivacaine as a parasternal nerve block in children post-cardiac surgery is an effective adjunct to pain management. This was a retrospective cohort study of all patients who underwent cardiothoracic surgery via median sternotomy at a large children’s hospital between November 2011 and February 2014 with and without bupivacaine following the introduction of perioperative bupivacaine in late 2012 on a single unit. 62 out of 148 patients (age 3–17 years) who received bupivacaine demonstrated decreased postoperative opioid use. Within one day of surgery, patients who received bupivacaine required, on average, 0.57 mg/kg (95% CI, 0.46 to 0.68) of total morphine equivalent compared to 0.93 mg/kg (95% CI, 0.80 to 1.06) for patients who did not receive bupivacaine. This difference was statistically significant after adjusting for potential confounders (p-value = 0.002). Length of stay and intubation were shorter on average among patients who received bupivacaine, but these differences were not statistically significant after adjusting for potential confounders. The study results seem to suggest that the perioperative administration of bupivacaine may reduce opioid usage among children post-cardiotomy.

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.

Clinical Management of Pain in Rodents

The use of effective regimens for mitigating pain remain underutilized in research rodents despite the general acceptance of both the ethical imperative and regulatory requirements intended to maximize animal welfare. Factors contributing to this gap between the need for and the actual use of analgesia include lack of sufficient evidence-based data on effective regimens, under-dosing due to labor required to dose analgesics at appropriate intervals, concerns that the use of analgesics may impact study outcomes, and beliefs that rodents recover quickly from invasive procedures and as such do not need analgesics. Fundamentally, any discussion of clinical management of pain in rodents must recognize that nociceptive pathways and pain signaling mechanisms are highly conserved across mammalian species, and that central processing of pain is largely equivalent in rodents and other larger research species such as dogs, cats, or primates. Other obstacles to effective pain management in rodents have been the lack of objective, science-driven data on pain assessment, and the availability of appropriate pharmacological tools for pain mitigation. To address this deficit, we have reviewed and summarized the available publications on pain management in rats, mice and guinea pigs. Different drug classes and specific pharmacokinetic profiles, recommended dosages, and routes of administration are discussed, and updated recommendations are provided. Nonpharmacologic tools for increasing the comfort and wellbeing of research animals are also discussed. The potential adverse effects of analgesics are also reviewed. While gaps still exist in our understanding of clinical pain management in rodents, effective pharmacologic and nonpharmacologic strategies are available that can and should be used to provide analgesia while minimizing adverse effects. The key to effective clinical management of pain is thoughtful planning that incorporates study needs and veterinary guidance, knowledge of the pharmacokinetics and mechanisms of action of drugs being considered, careful attention to individual differences, and establishing an institutional culture that commits to pain management for all species as a central component of animal welfare.

Revisiting Tramadol: A Multi-Modal Agent for Pain Management

Tramadol-an atypical opioid analgesic-has a unique pharmacokinetic and pharmacodynamic profile, with opioidergic, noradrenergic, and serotonergic actions. Tramadol has long been used as a well-tolerated alternative to other drugs in moderate pain because of its opioidergic and monoaminergic activities. However, cumulative evidence has been gathered over the last few years that supports other likely mechanisms and uses of tramadol in pain management. Tramadol has modulatory effects on several mediators involved in pain signaling, such as voltage-gated sodium ion channels, transient receptor potential V1 channels, glutamate receptors, α₂-adrenoceptors, adenosine receptors, and mechanisms involving substance P, calcitonin gene-related peptide, prostaglandin E₂, and proinflammatory cytokines. Tramadol also modifies the crosstalk between neuronal and non-neuronal cells in peripheral and central sites. Through these molecular effects, tramadol could modulate peripheral and central neuronal hyperexcitability. Given the broad spectrum of molecular targets, tramadol as a unimodal analgesic relieves a broad range of pain types, such as postoperative, low back, and neuropathic pain and that associated with labor, osteoarthritis, fibromyalgia, and cancer. Moreover, tramadol has anxiolytic, antidepressant, and anti-shivering activities that could improve pain management outcomes. The aim of this review was to address these issues in the context of maladaptive physiological and psychological processes that are associated with different pain types.

Chronified Pain Following Operative Procedures

BACKGROUND

Over 18 million operative procedures are performed each year in Germany alone. Approximately 10% of surgical patients develop moderate to severe chronic post-surgical pain (CPSP), which can severely impair their quality of life. The pain must persist for at least three months to be called chronic; pain that arises after a symptom-free interval is not excluded. The perioperative use of local anesthetic agents may lessen the incidence of CPSP.

METHODS

We selectively reviewed the pertinent literature, including two current Cochrane Reviews. Local and regional anesthetic techniques are discussed, as is the intravenous administration of lidocaine.

RESULTS

The main risk factors for CPSP are pre-existing (preoperative) chronic pain, opioid intake, a pain-related catastrophizing tendency, intraoperative nerve injury, and severe acute postoperative pain. CPSP is reported to be especially common after thoracic surgery, breast surgery, amputations, and orthopedic procedures. Local and regional anesthetic techniques have been shown to significantly lower the incidence of CPSP after thoracotomy (number needed to treat for an additional beneficial outcome [NNTB] = 7), breast cancer surgery (NNTB = 7), and cesarean section (NNTB = 19). Intravenous lidocaine also lowers the incidence of CPSP after various types of procedures.

CONCLUSION

Local and regional anesthetic techniques and intravenous lidocaine lower the incidence of CPSP after certain types of operative procedures. The intravenous administration of lidocaine to prevent CPSP is off label and requires the patient's informed consent. The evidence for the measures presented here is of low to medium quality.