Local Anesthetic Systemic Toxicity: A Review of Recent Case Reports and Registries

Evaluation of a multidisciplinary simulation training curriculum for local anesthetic systemic toxicity management: a quasi-experimental study using the Kirkpatrick model in India

BACKGROUND

Local anesthetic systemic toxicity (LAST) is a rare life-threatening complication of regional anesthesia. Simulation-based training offers an effective educational approach to improve the management of infrequent events. This quasi-experimental study assessed the impact of a multidisciplinary simulation-based educational intervention on managing LAST as a real peri-operative team.

METHODS

Twelve anesthesia trainees and eight nursing staff members participated in the study. The intervention included pre-course learning materials, cognitive aids, and immersive simulation scenarios. Simulation scenarios were conducted at baseline (O1), one week after a boot camp (O2), and six months later (O3). Participants' reactions to the training were evaluated using a 5-point Likert scale, while knowledge acquisition was measured through pre- and post-test questionnaires. Team-based skills acquisition and retention were assessed using a modified checklist from the simulation team assessment tool. Data were analyzed using paired t-tests, with P < 0.05 considered statistically significant.

RESULTS

All participants rated the LAST curriculum as satisfactory to very satisfactory. Significant improvements in both technical and non-technical skills were observed post-intervention (O2), with checklist scores increasing from an average of 39 (4.2) (95% confidence interval [CI], 34.88; 43.11) at O1 to 83.5 (5.7) (95% CI, 77.91; 89.08) at O2 (mean difference, 44.5; P < 0.001). At six months (O3), skill retention was indicated by an average score of 72 (7.8) (95% CI, 62.36; 77.64).

CONCLUSIONS

Multidisciplinary, simulation-based educational interventions remarkably improve knowledge and skills related to LAST management, with effective skill retention observed at six months when implemented by multiprofessional teams in real-world settings.

Investigation of the Protective Effects of Dexmedetomidine, Midazolam, Propofol, and Intralipid on Oxidative Stress and Inflammation in Rats with Lidocaine-Induced Toxicity

Aim

The aim of this study was to compare the effects of dexmedetomidine, midazolam, propofol, and intralipid on lidocaine-induced cardiotoxicity and neurotoxicity.

Methods

Forty-eight male Sprague-Dawley rats were randomly divided into six groups (n = 8 per group): control (C), lidocaine (L), lidocaine + dexmedetomidine (LD), lidocaine + midazolam (LM), lidocaine + propofol (LP), and lidocaine + intralipid (LI). Dexmedetomidine (100 µg/kg), midazolam (4 mg/kg), propofol (40 mg/kg), and intralipid (10 mg/kg) were administered intraperitoneally as pretreatment. Lidocaine (90 mg/kg) was administered intraperitoneally to induce oxidative stress in all groups except the control. After 60 minutes of electrocardiography (ECG) recording, the rats were sacrificed, and heart and brain tissue samples were collected. Comparative measurements of total oxidant status (TOS), total antioxidant status (TAS), oxidative stress index (OSI), and inflammatory parameters were conducted.

Results

In heart tissue samples, TAS was significantly higher in LI and LD groups (p < 0.05). Additionally, oxidative stress was significantly higher in the LM group (p < 0.05). Despite an increase in oxidative stress in brain tissue samples across all groups, it was found that all groups exhibited antioxidant protective effects (p < 0.05). Inflammatory parameters in heart and brain tissues significantly decreased in all groups, especially in the LI group (p < 0.05).

Conclusion

It was observed that pretreatment with midazolam increased oxidative stress induced by lidocaine, while dexmedetomidine and intralipid exhibited greater antioxidant effects. Dexmedetomidine and intralipid used as pretreatment were shown to be more effective in protecting against oxidative stress and inflammation.

Local Anesthetic Systemic Toxicity in an Infant Following a Caudal Block: A Case Report and Review of Literature

Local anesthetic systemic toxicity (LAST) is a rare but serious complication of regional anesthesia, particularly in neonates and infants due to their immature hepatic metabolism, reduced protein-binding capacity, and increased vascular absorption. We report the case of a two-month-old ex-premature infant who developed ventricular fibrillation following a caudal block with bupivacaine during hernia repair and circumcision. Despite negative aspiration tests, systemic absorption of bupivacaine led to toxic plasma concentrations, resulting in sudden cardiovascular collapse without preceding neurological symptoms, a presentation typical in pediatric LAST. Immediate resuscitation, including cardiopulmonary resuscitation, epinephrine, and lipid emulsion therapy, successfully restored normal cardiac rhythm. This case underscores the importance of vigilance, strict adherence to weight-based dosing, and the availability of lipid emulsion therapy in pediatric anesthesia while emphasizing prevention through careful technique, monitoring, and the use of ultrasound guidance to minimize the risk of this life-threatening complication.

CPL-01, an investigational long-acting ropivacaine, demonstrates safety and efficacy in open inguinal hernia repair

BACKGROUND

There is an unmet medical need for effective nonopioid analgesics that can decrease pain while reducing systemic opioid use. CPL-01, an extended-release injectable formulation of ropivacaine, is designed to safely provide analgesia and reduce or eliminate opioid use in the postoperative period.

METHODS

Subjects undergoing open inguinal hernia with mesh were prospectively randomized to 1 of 3 doses of CPL-01 (10, 20, or 30 ml of 2% CPL-01, n = 14, 12, and 14, respectively), Naropin (150 mg, n = 40), or saline placebo (n = 13) infiltrated into the surgical site prior to closure. Pain and rescue medication usage was assessed, and Numeric Rating Scale (NRS) pain scores were adjusted for opioid usage using windowed worst observation carried forward (wWOCF) imputation. The primary efficacy endpoint was the mean area under the curve (AUC) of the NRS pain intensity scores with activity.

RESULTS

Ninety-three subjects were treated, and 91 subjects completed 72 h of post-operative monitoring. Subjects who received the highest dose of CPL-01 in Cohort 3 showed a clinically meaningful reduction in postoperative pain intensity scores, which was the lowest value for any treatment in all cohorts, showing a trend towards statistical significance as compared to the pooled placebo group (p = 0.08), and numerically better than the 40 subjects who received Naropin. Opioid use through 72 h in subjects who received CPL-01 in Cohort 3 was approximately half of that shown in the placebo and Naropin groups; approximately 2/3 of the CPL-01 subjects (9/14) required no opioids at all through the first 72 h after the operation. More CPL-01 subjects avoided severe pain and were ready for discharge earlier than other groups. CPL-01 was safe and well-tolerated, with no clinically meaningful safety signals, and showed predictable and consistent extended-release pharmacokinetics.

CONCLUSION

Results suggest that CPL-01 may be the first long-acting ropivacaine to address postoperative pain while reducing the need for opioids.

Utility of the occipital nerve block in the emergency department: A case series

INTRODUCTION

Tension headaches, as well as various scalp pathologies including lacerations and abscesses are commonly treated in the emergency department (ED). The occipital nerve block (ONB), previously described in anesthesia and neurology literature, offers analgesia of the posterior scalp on the side ipsilateral to the injection while maintaining a low adverse effect profile.

CASE REPORT

We report three cases in which ONB was utilized for tension headache, scalp laceration repair, and incision and drainage of scalp abscess. These patients all reported significant pain improvement without any reported complications.

CONCLUSION

The ONB is a landmark based technique that offers an opportunity to provide analgesia in the ED that is simple, effective, and without known significant risks that are associated with other modalities of treatment.

Local Anesthetic Systemic Toxicity in Cardiac Surgery Patient with Erector Spinae Plane Catheter: A Case Report

Regional anesthesia nerve blocks are increasingly used for patients undergoing cardiac surgery as part of multimodal pain management. Though rare, local anesthetic systemic toxicity (LAST) is a severe complication that requires vigilant monitoring. We present a case of a postcardiac surgery patient who developed LAST multiple days after surgery from lidocaine via an erector spinae plane catheter. This episode was determined to be a result of impaired lidocaine metabolism from liver shock caused by worsening pulmonary hypertension. Even under continuous monitoring, patients with cardiac or liver dysfunction are at increased risk of complications from local anesthetics.

Local anesthetic dosing and toxicity of adult truncal catheters: a narrative review of published practice

BACKGROUND/IMPORTANCE

Anesthesiologists frequently use truncal catheters for postoperative pain control but with limited characterization of dosing and toxicity.

OBJECTIVE

We reviewed the published literature to characterize local anesthetic dosing and toxicity of paravertebral and transversus abdominis plane catheters in adults.

EVIDENCE REVIEW

We searched the literature for bupivacaine or ropivacaine infusions in the paravertebral or transversus abdominis space in humans dosed for 24 hours. We evaluated bolus dosing, infusion dosing and cumulative 24-hour dosing in adults. We also identified cases of local anesthetic systemic toxicity and toxic blood levels.

FINDINGS

Following screening, we extracted data from 121 and 108 papers for ropivacaine and bupivacaine respectively with a total of 6802 patients. For ropivacaine and bupivacaine, respectively, bolus dose was 1.4 mg/kg (95% CI 0.4 to 3.0, n=2978) and 1.0 mg/kg (95% CI 0.18 to 2.1, n=2724); infusion dose was 0.26 mg/kg/hour (95% CI 0.06 to 0.63, n=3579) and 0.2 mg/kg/hour (95% CI 0.06 to 0.5, n=3199); 24-hour dose was 7.75 mg/kg (95% CI 2.1 to 15.7, n=3579) and 6.0 mg/kg (95% CI 2.1 to 13.6, n=3223). Twenty-four hour doses exceeded the package insert recommended upper limit in 28% (range: 17%-40% based on maximum and minimum patient weights) of ropivacaine infusions and 51% (range: 45%-71%) of bupivacaine infusions. Toxicity occurred in 30 patients and was associated with high 24-hour dose, bilateral catheters, cardiac surgery, cytochrome P-450 inhibitors and hypoalbuminemia.

CONCLUSION

Practitioners frequently administer ropivacaine and bupivacaine above the package insert limits, at doses associated with toxicity. Patient safety would benefit from more specific recommendations to limit excessive dose and risk of toxicity.

Local anesthetic dosing and toxicity of pediatric truncal catheters: a narrative review of published practice

BACKGROUND/IMPORTANCE

Despite over 30 years of use by pediatric anesthesiologists, standardized dosing rates, dosing characteristics, and cases of toxicity of truncal nerve catheters are poorly described.

OBJECTIVE

We reviewed the literature to characterize dosing and toxicity of paravertebral and transversus abdominis plane catheters in children (less than 18 years).

EVIDENCE REVIEW

We searched for reports of ropivacaine or bupivacaine infusions in the paravertebral and transversus abdominis space intended for 24 hours or more of use in pediatric patients. We evaluated bolus dosing, infusion dosing, and cumulative 24-hour dosing in patients over and under 6 months. We also identified cases of local anesthetic systemic toxicity and toxic blood levels.

FINDINGS

Following screening, we extracted data from 46 papers with 945 patients.Bolus dosing was 2.5 mg/kg (median, range 0.6-5.0; n=466) and 1.25 mg/kg (median, range 0.5-2.5; n=294) for ropivacaine and bupivacaine, respectively. Infusion dosing was 0.5 mg/kg/hour (median, range 0.2-0.68; n=521) and 0.33 mg/kg/hour (median, range 0.1-1.0; n=423) for ropivacaine and bupivacaine, respectively, consistent with a dose equivalence of 1.5:1.0. A single case of toxicity was reported, and pharmacokinetic studies reported at least five cases with serum levels above the toxic threshold.

CONCLUSIONS

Bolus doses of bupivacaine and ropivacaine frequently comport with expert recommendations. Infusions in patients under 6 months used doses associated with toxicity and toxicity occurred at a rate consistent with single-shot blocks. Pediatric patients would benefit from specific recommendations about ropivacaine and bupivacaine dosing, including age-based dosing, breakthrough dosing, and intermittent bolus dosing.

2023 American Heart Association Focused Update on the Management of Patients With Cardiac Arrest or Life-Threatening Toxicity Due to Poisoning: An Update to the American Heart Association Guidelines for Cardiopulmonary Resuscitation and Emergency Cardiovascular Care

In this focused update, the American Heart Association provides updated guidance for resuscitation of patients with cardiac arrest, respiratory arrest, and refractory shock due to poisoning. Based on structured evidence reviews, guidelines are provided for the treatment of critical poisoning from benzodiazepines, β-adrenergic receptor antagonists (also known as β-blockers), L-type calcium channel antagonists (commonly called calcium channel blockers), cocaine, cyanide, digoxin and related cardiac glycosides, local anesthetics, methemoglobinemia, opioids, organophosphates and carbamates, sodium channel antagonists (also called sodium channel blockers), and sympathomimetics. Recommendations are also provided for the use of venoarterial extracorporeal membrane oxygenation. These guidelines discuss the role of atropine, benzodiazepines, calcium, digoxin-specific immune antibody fragments, electrical pacing, flumazenil, glucagon, hemodialysis, hydroxocobalamin, hyperbaric oxygen, insulin, intravenous lipid emulsion, lidocaine, methylene blue, naloxone, pralidoxime, sodium bicarbonate, sodium nitrite, sodium thiosulfate, vasodilators, and vasopressors for the management of specific critical poisonings.

Major complications of caudal block: A prospective survey of 973 cases in adult anorectal surgery

Background

We conducted a prospective study of surgical inpatients at a teaching hospital to assess the incidence and potential risk factors for major complications of caudal anesthesia in anorectal surgery.

Methods

A total of 973 patients undergoing anorectal surgery under caudal block were included in this prospective, observer-blinded trial after providing consent. Demographic information, detailed perioperative information, anesthesia-related complications and postoperative follow-up information were recorded. Meanwhile, the incidence and risk factors for major caudal anesthesia-related complications were analyzed.

Results

A total of 973 patients underwent caudal block. The effective rate was 95.38 % (928 cases). However, there were still 38 (3.91 %) cases with insufficient block and 7 (0.72 %) cases with no block. The major anesthesia-related complications were local anesthetic systemic toxicity (9, 0.92 %), cauda equine syndrome (1, 0.10 %), transient neurological symptoms (3, 0.31 %) and localized pain at the caudal insertion site (30, 3.08 %). The identified risk factor for local anesthetic systemic toxicity was multiple attempts locating the caudal space (OR = 5.30; 1.21-23.29). The identified risk factor for localized pain at the caudal insertion site was multiple attempts locating the caudal space (OR = 10.57; 4.89-22.86).

Conclusion

The main complications of caudal block in adult patients are transient neurological symptoms, cauda equine syndrome, serious local anesthetic systemic toxicity and localized pain at the caudal insertion site. Overall, the incidence of complications is low and symptoms are mild. Caudal block is still a safe and reliable method for anesthesia in adult anorectal surgery.

Lipid emulsion therapy during management of the critically-ill poisoned patient: a prospective cohort study

BACKGROUND

Despite conflicting data, intravenous lipid emulsion has emerged as a potential antidote. The "lipid sink" theory suggests that following intravenous administration of lipid, lipophilic drugs are sequestered in the vascular compartment, thereby reducing their tissue concentrations. This study sought to determine if survival is associated with the intoxicant's degree of lipophilicity.

METHODS

We reviewed all cases in the Toxicology Investigators Consortium's lipid sub-registry between May 2012 through December 2018. Information collected included demographics, exposure circumstances, clinical course, management, disposition, and outcome. The primary outcome was survival after lipid emulsion therapy. Survival was stratified by the log of the intoxicant's octanol-water partition coefficient. We also assessed the association between intoxicant lipophilicity and an increase in systolic blood pressure after lipid emulsion administration.

RESULTS

We identified 134 patients, including 81 (60.4%) females. The median age was 40 years (interquartile range 21-75). One hundred and eight (80.6%) patients survived, including 45 (33.6%) with cardiac arrest during their intoxication. Eighty-two (61.2%) were hypotensive, and 98 (73.1%) received mechanical ventilation. There was no relationship between survival and the log of the partition coefficient of the intoxicant on linear analysis (P = 0.89) or polynomial model (P = 0.10). Systolic blood pressure increased in both groups. The median (interquartile range) systolic blood pressure before lipid administration was 68 (60-78) mmHg for those intoxicants with a log partition coefficient < 3.6 compared with 89 (76-104) mmHg after lipid administration. Among those drugs with a log partition coefficient > 3.6, the median (interquartile range) was 69 (60-84) mmHg before lipid and 89 (80-96) mmHg after lipid administration.

CONCLUSION

Most patients in this cohort survived. Lipophilicity was not correlated with survival or the observed changes in blood pressure. The study did not address the efficacy of lipid emulsion.

Pharmacological Methods of Pain Management: Narrative Review of Medication Used

Background

Pain management is a critical aspect of healthcare, aimed at alleviating discomfort and improving the quality of life for individuals experiencing acute or chronic pain. Pharmacological methods constitute a primary approach to pain management, including a diverse array of drugs that work through different mechanisms.

Aim

Identifying medications commonly employed in pain management, focusing on their mechanism of actions, uses, efficacy and pharmacological applications.

Methods

The methodology involved a systematic search of scientific literature using various databases, including PubMed, Scopus, and Google Scholar. Relevant articles published between 2000 and 2023 were screened for inclusion. The selected studies encompassed original research, review articles, therapeutic guidelines and randomized controlled trials.

Results

The findings of this review suggest that a multimodal approach combining various analgesics can enhance pain relief while minimizing adverse effects. It emphasizes the importance of assessing pain intensity, determining the underlying etiology, and utilizing evidence-based guidelines to optimize pain management outcomes.

Conclusion

Pharmacological methods of pain management are an essential component of pain management strategies to achieve optimal pain relief while minimizing adverse effects. The article concludes with a discussion on emerging trends and future directions in pharmacological pain management, including novel drug targets and advances in drug delivery systems.

Local Anesthetics, Clinical Uses, and Toxicity: Recognition and Management

Local anesthetic (LA) compounds decrease the permeability of the ion channels to sodium, which in turn, diminishes the rate of depolarization. These agents (a.k.a. -caines) are also used to depress mucosal sensations, e.g., gag reflex in the form of topical anesthetics. Overdose of LA can lead to local anesthetic systemic toxicity (LAST), which is the precursor of potentially lethal consequences on clinical grounds. There is a wide array of possible presentations of LAST, from mild findings, such as temporary hypertensive events, to serious conditions, including refractory cardiac dysfunction, dysrhythmias and prearrest situations. Lidocaine, prilocaine, mepivacaine, ropivacaine, and bupivacaine are among the most commonly used members of the family. The agents' dosages should be adjusted in children, elderly and fragile individuals and those with organ failures, as the metabolism of the compounds will be impaired. The ideal body weight, along with hepatic and renal functional reserves, will have an impact on elimination kinetics. Systemic absorption is an untoward consequence of LA administration which deserves every means of prevention. Intravenous lipid emulsion is an important life-saving treatment in severe, life-threatening cases. This narrative review article is designed to cover the clinical uses of LA in children, recognition, and management of untoward effects of the agents, with special emphasis on the LAST.

Local Anesthetic Systemic Toxicity Following Inadvertent Intravenous Levobupivacaine Infusion in Infants: A Case Report

Background and objectives: Local anesthetic systemic toxicity (LAST) in children is extremely rare, occurring at an estimated rate of 0.76 cases per 10,000 procedures. However, among reported cases of LAST in the pediatric population, infants and neonates represent approximately 54% of reported LAST cases. We aim to present and discuss the clinical case of LAST with full clinical recovery due to accidental levobupivacaine intravenous infusion in a healthy 1.5-month-old patient, resulting in cardiac arrest necessitating resuscitation. Case presentation: A 4-kilogram, 1.5-month-old female infant, ASA I, presented to the hospital for elective herniorrhaphy surgery. Combined anesthesia was planned, involving general endotracheal and caudal anesthesia. After anesthesia induction, cardiovascular collapse was noticed, resulting in bradycardia and later cardiac arrest with EMD (Electromechanical Dissociation). It was noticed that during induction, levobupivacaine was accidentally infused intravenously. A local anesthetic was prepared for caudal anesthesia. LET (lipid emulsion therapy) was started immediately. Cardiopulmonary resuscitation was carried out according to the EMD algorithm, which lasted 12 min until spontaneous circulation was confirmed and the patient was transferred to the ICU. In ICU, the girl was extubated the second day, and the third day she was transferred to the regular pediatric unit. Finally, the patient was discharged home after a total of five days of hospitalization with full clinical recovery. A four-week follow-up has revealed that the patient recovered without any neurological or cardiac sequelae. Conclusions: The clinical presentation of LAST in children usually begins with cardiovascular symptoms because pediatric patients are already under general anesthesia when anesthetics are being used, as was the case in our case. Treatment and management of LAST involve cessation of local anesthetic infusion, stabilization of the airway, breathing, and hemodynamics, as well as lipid emulsion therapy. Early recognition of LAST as well as immediate CPR if needed and targeted treatment for LAST can lead to good outcomes.

Multidisciplinary simulation of local anaesthetic systemic toxicity improves diagnostic and treatment skills and self-confidence for pain clinic procedural staff

Local anaesthetic systemic toxicity (LAST) is a rare complication after outpatient interventional pain procedures, which can present as an emergent and life-threatening condition. Proficiency and confidence in managing this rare situation necessitates strategies to ensure team members can perform necessary tasks. The primary objective was to familiarse the pain clinic procedural staff-physicians, nurses, medical assistants, and radiation technologists-with concise and current instruction and an opportunity to practice in a controlled environment. A two-part series was designed and led by the pain physicians, with the assistance of the simulation centre and clinic staff. A 20 min didactic session was held to familiarise the providers with relevant details and information regarding LAST. Then, 2 weeks later, all team members participated in a simulation exercise intended to portray a LAST encounter, tasking participants to recognise and manage the condition in a team-based model. Before and after the didactic and simulation sessions, the staff was administered a questionnaire to assess knowledge of LAST signs, symptoms, management strategies, and priorities. Respondents were better able to identify signs and symptoms of toxicity and prioritise management steps, and felt more confident in recognising symptoms, starting treatment and coordinating care. Furthermore, participants emphasised the positive of debriefing, practicing a rare situation and learning strategies for effective communication, team dynamics and role clarity.

FORMAT

Small group didactic session, simulation exercise in a clinical simulation lab.

TARGET AUDIENCE

Attending, fellow, and resident physicians, medical students, registered nurses, certified medical assistants, and radiation technologists working in a pain clinic procedure suite.

OBJECTIVES

To acquaint the pain clinic procedural staff with current training related to LAST and an opportunity to practice in a controlled environment.

Randomized controlled trial (RCT) comparing ultrasound-guided pudendal nerve block with ultrasound-guided penile nerve block for analgesia during pediatric circumcision

INTRODUCTION

Optimal analgesia for circumcision is still debated. The dorsal penile nerve block has been shown to be superior to topical and caudal analgesia. Recently, the ultrasound-guided pudendal nerve block (group pudendal) has been popularized. This randomized, blinded clinical trial compared group pudendal with ultrasound-guided dorsal penile nerve block (group penile) under general anesthesia for pediatric circumcision.

METHODS

Prepubertal males aged 1-12 years undergoing elective circumcision were randomized to either group. The primary outcome was postoperative face, legs, activity, cry, consolability (FLACC) scores. Our secondary outcomes included parent's postoperative pain measure, analgesic consumption during the first 24 hours, surgeon's and parent's satisfaction, time to perform the block, hemodynamic changes intraoperatively and total time in postanesthesia care unit and until discharge.

RESULTS

A total of 155 patients were included for analysis (77 in group pudendal and 78 in group penile). Mean age was 7.3 years old. FLACC scores were not statistically different between groups (p=0.19-0.97). Surgeon satisfaction was higher with group pudendal (90.8% vs 56.6% optimal, p<0.01). Intraoperative hemodynamic changes (>20% rise of heart rate or blood pressure) were higher in group pudendal (33.8% vs 9.0%, p<0.01) as was intraoperative fentanyl use (1.3 vs 1.0 μg/kg, p<0.01). Other secondary outcomes were not statistically different.

DISCUSSION

Both ultrasound-guided blocks, performed under general anesthesia, provide equivalent postoperative analgesia for pediatric circumcision as evidenced by low pain scores and opioid consumption. Surgeon satisfaction was higher in the pudendal group.

TRIAL REGISTRATION NUMBER

NCT03914365.

Cardiac Arrest after Small Doses Ropivacaine: Local Anesthetic Systemic Toxicity in the Course of Continuous Femoral Nerve Blockade

BACKGROUND

The paper presents a case report of an episode of local anesthetic systemic toxicity (LAST) with cardiac arrest after continuous femoral nerve blockade.

CASE REPORT

A 74-year-old patient burdened with hypertension and osteoarthritis underwent elective total knee replacement surgery. After surgery, a continuous femoral nerve blockade was performed and an infusion of a local anesthetic (LA) was started using an elastomeric pump. Five hours after surgery, the patient had an episode of generalized seizures followed by cardiac arrest. After resuscitation, spontaneous circulation was restored. In the treatment, 20% lipid emulsion was used. On day two of the ICU stay, the patient was fully cardiovascularly and respiratorily stable without neurological deficits and was discharged to the orthopedic department to continue treatment.

CONCLUSION

Systemic toxicity of LA is a serious and potentially fatal complication of the use of LA in clinical practice. It should be noted that in nearly 40% of patients, LAST deviates from the classic and typical course and may have an atypical manifestation, and the first symptoms may appear with a long delay, especially when continuous blockades are used. Therefore, the proper supervision of the patient and the developed procedure in the event of LAST is undoubtedly important here.

Local Anesthetic Systemic Toxicity After Local Infiltration Analgesia Following a Total Knee Arthroplasty

Multimodal analgesia is nowadays a recognized method to reduce postoperative pain. Infiltration of the surgical site with local anesthetic is one of the methods widely used for its effectiveness and its lower risk of toxicity, particularly in orthopedic surgery. We present here a case of local anesthetic systemic toxicity (LAST) that occurred on two different occasions to the same patient after total knee replacement surgeries. The clinical presentation of the syndrome was not typical for this 74-year-old patient who presented with respiratory distress associated with impaired consciousness. After the elimination of the most common diagnoses, it was finally the administration of Intralipid that followed with clinical improvement.

Sudden quadriparesis after non-overdose local anesthesia

Background

A well-known anesthetic, lidocaine is the most widely used local anesthetic. Local anesthetic systemic toxicity (LAST) is a life-threatening event with common and prominent presentations of central nervous system (CNS) toxicity and cardiovascular toxicity. The most frequent and prominent early warning signs and symptoms of LAST are central nervous system symptoms. While rare, cases quadriparesis after the administration of lidocaine has been reported.

Case presentation

In this paper, we report a very rare case of quadriparesis after local anesthesia administration for vocal cord cyst-removal surgery, which dramatically improved after treatment. LAST can occur during various routes of lidocaine administration, such as local spray. A possible mechanism of our case could be the local diffusion of lidocaine to the spinal cord, which caused the symptoms to mimic anterior cord syndrome.

Conclusions

Our case presented a favorable outcome following the administration of intravenous lipid emulsion (ILE) for non-over dose local anesthetic drug induced spinal cord inhibition symptoms. These findings highlight the need for further research on the use of ILE to reverse LAST and other adverse effects of local anesthetics.

[Generalized seizure during placement of an axillary plexus block]

A young patient experienced a generalized seizure during the placement of an axillary plexus block. The mechanisms, essentially the presumed intravascular administration, which led to the local anesthetic toxicity as the cause of this event, are discussed. This case is an example of how visualization of the anatomy by ultrasound can give a false impression when certain details are not respected. It is assumed that the main mechanism in this case was venous compression by the ultrasound transducer.

Dose-dependent effects of high intensity focused ultrasound on compound action potentials in an ex vivo rodent peripheral nerve model: comparison to local anesthetics

Background

In animal models, focused ultrasound can reversibly or permanently inhibit nerve conduction, suggesting a potential role in managing pain. We hypothesized focused ultrasound’s effects on action potential parameters may be similar to those of local anesthetics.

Methods

In an ex vivo rat sciatic nerve model, action potential amplitude, area under the curve, latency to 10% peak, latency to 100% peak, rate of rise, and half peak width changes were assessed after separately applying increasing focused ultrasound pressures or concentrations of bupivacaine and ropivacaine. Focused ultrasound’s effects on nerve structure were examined histologically.

Results

Increasing focused ultrasound pressures decreased action potential amplitude, area under the curve, and rate of rise, increased latency to 10% peak, and did not change latency to 100% peak or half peak width. Increasing local anesthetic concentrations decreased action potential amplitude, area under the curve, and rate of rise and increased latency to 10% peak, latency to 100% peak, and half peak width. At the highest focused ultrasound pressures, nerve architecture was altered compared with controls.

Discussion

While some action potential parameters were altered comparably by focused ultrasound and local anesthetics, there were small but notable differences. It is not evident if these differences may lead to differences in clinical pain effects when focused ultrasound is applied in vivo or if focused ultrasound pressures that result in clinically relevant changes damage nerve structures. Given the potential advantages of a non-invasive technique for managing pain conditions, further investigation may be warranted in an in vivo pain model.

A randomized trial to determine the minimum effective lidocaine volume for median nerve block using hydrodissection

Ultrasound-guided hydrodissection with 5% dextrose in water (DW5) creates a peri-nervous compartment, separating the nerve from the neighboring anatomical structures. The aim of this randomized study was to determine the minimum volume of lidocaine 2% with epinephrine 1:200,000 required when using this technique to achieve an effective median nerve block at the elbow in 95% of patients (MEAV95). Fifty-two patients scheduled for elective hand surgery received an ultrasound-guided circumferential perineural injection of 4 ml DW5 and an injection of local anesthetic (LA) following a biased coin up-and-down sequential allocation method. A successful block was defined as a light touch completely suppressed on the two distal phalanges of the index finger within a 30-min evaluation period. The MEAV95 of lidocaine 2% with epinephrine was 4 ml [IQR 3.5–4.0]. Successful median nerve block was obtained in 38 cases (82.6%) with median onset time of 20.0 [10.0–21.2] minutes (95% CI 15–20). The analgesia duration was 248 [208–286] minutes (95% CI 222–276). Using an ultrasound-guided hydrodissection technique with DW5, the MEAV95 to block the median nerve at the elbow with 2% lidocaine with epinephrine was 4 ml [IQR 3.5–4.0]. This volume is close to that usually recommended in clinical practice.

Trial registration clinicaltrials.gov. NCT02438657, Date of registration: May 8, 2015.

The Options for Neuraxial Drug Administration

Neuraxial drug administration, i.e., the injection of drugs into the epidural or intrathecal space to produce anesthesia or analgesia, is a technique developed more than 120 years ago. Today, it still is widely used in daily practice in anesthesiology and in acute and chronic pain therapy. A multitude of different drugs have been introduced for neuraxial injection, only a part of which have obtained official approval for that indication. A broad understanding of the pharmacology of those agents is essential to the clinician to utilize them in a safe and efficient manner. In the present narrative review, we summarize current knowledge on neuraxial anatomy relevant to clinical practice, including pediatric anatomy. Then, we delineate the general pharmacology of neuraxial drug administration, with particular attention to specific aspects of epidural and intrathecal pharmacokinetics and pharmacodynamics. Furthermore, we describe the most common clinical indications for neuraxial drug administration, including the perioperative setting, obstetrics, and chronic pain. Then, we discuss possible neurotoxic effects of neuraxial drugs, and moreover, we detail the specific properties of the most commonly used neuraxial drugs that are relevant to clinicians who employ epidural or intrathecal drug administration, in order to ensure adequate treatment and patient safety in these techniques. Finally, we give a brief overview on new developments in neuraxial drug therapy.

Influence of Pharyngeal Anaesthesia on Post-Bronchoscopic Coughing: A Prospective, Single Blinded, Multicentre Trial

Background: Local anaesthesia of the pharynx (LAP) was introduced in the era of rigid bronchoscopy (which was initially a conscious procedure under local anaesthetic), and continued into the era of flexible bronchoscopy (FB) in order to facilitate introduction of the FB. LAP reduces cough and gagging reflex, but its post-procedural effect is unclear. This prospective multicentre trial evaluated the effect of LAP on coughing intensity/time and patient comfort after FB, and the feasibility of FB under propofol sedation alone, without LAP. Material and methods: FB was performed in 74 consecutive patients under sedation with propofol, either alone (35 patients, 47.3%) or with additional LAP (39 patients, 52.7%). A primary endpoint of post-procedural coughing duration in the first 10 min after awakening was evaluated. A secondary endpoint was the cough frequency, quality and development of coughing in the same period during the 10 min post-procedure. Finally, the ease of undertaking the FB and the patient’s tolerance and safety were evaluated from the point of view of the investigator, the assistant technician and the patient. Results: We observed a trend to a shorter cumulative coughing time of 48.6 s in the group without LAP compared to 82.8 s in the group receiving LAP within the first 10 min after the procedure, although this difference was not significant (p = 0.24). There was no significant difference in the cough frequency, quality, peri-procedural complication rate, nor patient tolerance or safety. FB, including any additional procedure, could be performed equally well with or without LAP in both groups. Conclusions: Our study suggests that undertaking FB under deep sedation without LAP does to affect post-procedural cough duration and frequency. However, further prospective randomised controlled trials are needed to further support this finding.

Lido-OH, a Hydroxyl Derivative of Lidocaine, Produced a Similar Local Anesthesia Profile as Lidocaine With Reduced Systemic Toxicities

Background: lidocaine is one of the most commonly used local anesthetics for the treatment of pain and arrhythmia. However, it could cause systemic toxicities when plasma concentration is raised. To reduce lidocaine’s toxicity, we designed a hydroxyl derivative of lidocaine (lido-OH), and its local anesthesia effects and systemic toxicity in vivo were quantitively investigated.

Method: the effectiveness for lido-OH was studied using mouse tail nerve block, rat dorsal subcutaneous infiltration, and rat sciatic nerve block models. The systemic toxicities for lido-OH were evaluated with altered state of consciousness (ASC), arrhythmia, and death in mice. Lidocaine and saline were used as positive and negative control, respectively. The dose-effect relationships were analyzed.

Results: the half effective-concentration for lido-OH were 2.1 mg/ml with 95% confident interval (CI95) 1.6–3.1 (lidocaine: 3.1 mg/ml with CI95 2.6–4.3) in tail nerve block, 8.2 mg/ml with CI95 8.0–9.4 (lidocaine: 6.9 mg/ml, CI95 6.8–7.1) in sciatic nerve block, and 5.9 mg/ml with CI95 5.8–6.0 (lidocaine: 3.1 mg/ml, CI95 2.4–4.0) in dorsal subcutaneous anesthesia, respectively. The magnitude and duration of lido-OH were similar with lidocaine. The half effective doses (ED₅₀) of lido-OH for ACS was 45.4 mg/kg with CI95 41.6–48.3 (lidocaine: 3.1 mg/kg, CI95 1.9–2.9), for arrhythmia was 16.0 mg/kg with CI95 15.4–16.8 (lidocaine: 3.0 mg/kg, CI95 2.7–3.3), and for death was 99.4 mg/kg with CI95 75.7–124.1 (lidocaine: 23.1 mg/kg, CI95 22.8–23.4). The therapeutic index for lido-OH and lidocaine were 35.5 and 5.6, respectively.

Conclusion: compared with lidocaine, lido-OH produced local anesthesia at similar potency and efficacy, but with significantly reduced systemic toxicities.

Multiple myeloma and malignant lesions: a potential risk factor for local anesthetic systemic toxicity

BACKGROUND

Multiple myeloma is a cancer of plasma cells that often leads to complications including osteolytic bone lesions, nephropathy and neuropathy. Multiple myeloma is only one etiology of many cancer pain conditions that may necessitate interventional pain treatment when refractory to multimodal medications. Notably, local anesthetic systemic toxicity is a rare but life-threatening complication of local anesthetic administered for these interventions.

CASE PRESENTATION

A 50-60-year-old woman presented with multiple myeloma complicated by chronic bone pain and in an acute pain crisis. A fluoroscopic-guided L4-5 epidural catheter was placed with clinical doses of bupivacaine for comfort to undergo MRI of the spine. Soon after, she became tachycardic, tachypneic and hypoxic requiring non-invasive positive pressure airway support. As this respiratory distress was attributed to a large pleural effusion, a pigtail catheter was inserted in the intensive care unit with submaximally dosed lidocaine infiltration. She then developed a left bundle branch block followed by cardiovascular collapse minimally responsive to high-dose inotrope and vasopressor support. Lipid emulsion was started with dramatic therapeutic response and recovery to baseline. A CT of the thoracolumbar spine showed worsening extensive lytic lesions throughout all vertebral bodies and ribs from diffuse myeloma.

CONCLUSIONS

Patients with oncologic lesions focal to the thoracolumbar spine may be at higher risk for local anesthetic systemic toxicity from palliative epidurals due to increased cancer-related angiogenesis. Likewise, local anesthetic infiltration for procedures near any malignant sites could have a similar risk and may require lower initial fractionated dosages with increased vigilance.

Postoperative Pain Management: Efficacy of Caudal Tramadol in Pediatric Lower Abdominal Surgery: A Randomized Clinical Study

BACKGROUND

One of the methods of pain control after pediatric surgical procedures is regional techniques, including caudal block, despite their limitations.

OBJECTIVES

In this study, the pain score and complications of caudal tramadol were evaluated in pediatrics following lower abdominal surgery.

METHODS

In this study, 46 children aged 3 to 10 years were allocated into two equal groups (R and TR) for performing caudal analgesia after lower abdominal surgery. The injectate contained 0.2% ropivacaine 1 mL/kg in the R group (control group) and tramadol (2 mg/kg) and ropivacaine in the TR group. The pain score, duration of pain relief, amount of paracetamol consumption, hemodynamic alterations, and possible complications at specific times (1, 2, and 6 hours) were evaluated in both groups.

RESULTS

No considerable difference was observed in the pain score between the groups in the first and second hours (P > 0.05). However, in the sixth hour, the TR group had a significantly lower pain score than the R group (P < 0.05). Compared to the R group, the TR group had a longer period of analgesia and lower consumption of analgesic drugs (P < 0.05). Heart rate and blood pressure differences were not significant between the two groups (P > 0.05). Similarly, the duration of operation and recovery time were not remarkably different between the two groups (P > 0.05). Complications had no apparent differences between these two groups, as well (P > 0.05).

CONCLUSIONS

In this study, the addition of tramadol to caudal ropivacaine in pediatric lower abdominal surgery promoted pain relief without complications.

Update on Local Anesthetic Toxicity, Prevention and Treatment During Regional Anesthesia in Infants and Children

Local anesthetic agents play a key role in the treatment and prevention of pain in children. Although generally safe and effective, as with any pharmacologic agent, adverse effects may occur with the administration of these medications. Systemic absorption or inadvertent systemic injection during bolus dosing or continuous infusion can result in local anesthetic systemic toxicity with life-threatening neurological and cardiac complications. The following article reviews the pharmacology of local anesthetic agents, outlines previous reports of systemic toxicity during regional anesthesia, and discusses prevention and treatment algorithms.

Development and Preliminary Validation of LoAD Calc, a Mobile App for Calculating the Maximum Safe Single Dose of Local Anesthetics

Local anesthetics systemic toxicity can lead to life-threatening situations. Correct calculation of the maximum safe dose is therefore paramount in preventing such complications. Different solutions have already emerged to support anesthesiologists but are seldom used in clinical practice as they require either access to a computer or specific documents to be at hand. A mobile app could provide an easy and practical solution; however, the few apps already created for this purpose often lack key elements, allowing invalid data to be entered and suggesting doses that might exceed the maximum safe dose. We describe the development of LoAD Calc, a mobile health (mHealth) app developed using a modified version of the Information Systems Research framework, which adds design thinking modes to the original framework. The app was enhanced through multiple iterations and developed with the aid of contextual observations and interviews, brainswarming sessions, prototyping, and continuous feedback. The design process led to the creation of two prototypes which underwent thorough testing by a sample of eight anesthesiologists. The final version of the app, LoAD Calc, was deployed on Apple and Android mobile test platforms and tested again by the same sample until deemed fit for release.

Local anesthetic systemic toxicity in children: a review of recent case reports and current literature

BACKGROUND

Local anesthetic systemic toxicity (LAST) in children occurs at an estimated rate of 8 per 100 000 blocks (95% CI 0.3 to 1.6). Due to the potential lethality of this iatrogenic complication, a better clarity of risk factors, clinical presentation, and prognosis may be clinically useful for contemporary treatment and prevention.

METHODS

An extensive literature search and detailed analysis of reported cases of LAST in patients less than 18 years of age published between April 2014 and August 2019 was performed. Clinical patterns were summarized.

RESULTS

Thirty-two cases of LAST were described in 17 published articles and 2 additional cases reported to lipidrescue.org, for a total of 34 cases. Three patients did not meet the inclusion criteria. Thirty-one cases were included in the analysis.

DISCUSSION

Infants represented a disproportionately large number of reports of LAST. The majority of local anesthetic doses were within currently published guidelines. Among the reported cases, penile and caudal blocks were the most commonly associated with LAST. Needle aspiration and test dosing with epinephrine failed to predict LAST with certainty. When LAST presented with severe cardiac compromise, intravenous lipid emulsion was given within 10 min in 43% of cases (13 of 30 reported cases). The vast majority of children were under general anesthesia when local anesthetic medications were administered. In children under general anesthesia, LAST presented with cardiac manifestations in 90% of cases (19 of 21 cases). There were no deaths or long-term morbidity reported.

Alleviation of prilocaine-induced epileptiform activity and cardiotoxicity by thymoquinone

PURPOSE

This study investigated whether thymoquinone (TQ) could alleviate central nervous system (CNS) and cardiovascular toxicity of prilocaine, a commonly used local anesthetic.

METHODS

Rats were randomized to the following groups: control, prilocaine treated, TQ treated and prilocaine + TQ treated. Electroencephalography and electrocardiography electrodes were placed and trachea was intubated. Mechanical ventilation was initiated, right femoral artery was cannulated for continuous blood pressure measurements and blood-gas sampling while the left femoral vein was cannulated for prilocaine infusion. Markers of myocardial injury, reactive oxygen/nitrogen species (ROS/RNS) generation and total antioxidant capacity (TAC) were assayed by standard kits. Aquaporin-4 (AQP4), nuclear factor(NF)κB-p65 and -p50 subunit in brain tissue were evaluated by histological scoring.

RESULTS

Blood pH and partial oxygen pressure, was significantly decreased after prilocaine infusion. The decrease in blood pH was alleviated in the prilocaine + TQ treated group. Prilocaine produced seizure activity, cardiac arrhythmia and asystole at significantly lower doses compared to prilocaine + TQ treated rats. Thymoquinone administration attenuated levels of myocardial injury induced by prilocaine. Prilocaine treatment caused increased ROS/RNS formation and decreased TAC in heart and brain tissue. Thymoquinone increased heart and brain TAC and decreased ROS/RNS formation in prilocaine treated rats. AQP4, NFκB-p65 and NFκB-p50 expressions were increased in cerebellum, cerebral cortex, choroid plexus and thalamic nucleus in prilocaine treated rats. Thymoquinone, decreased the expression of AQP4, NFκB-p65 and NFκB-p50 in brain tissue in prilocaine + TQ treated rats.

CONCLUSION

Results indicate that TQ could ameliorate prilocaine-induced CNS and cardiovascular toxicity.

Quadratus Lumborum Blocks in Nephrectomy: A Narrative Review

The quadratus lumborum block is a novel truncal block where local anaesthetic is injected adjacent to the quadratus lumborum muscle. It is used for caesarean sections, hip arthroplasty, gynecologic surgery, colectomy, and recently nephrectomy. To date, there are no reviews that outline the efficacy and performance of the quadratus lumborum blocks in patients receiving laparoscopic nephrectomy. The objective of this project was to outline the current available data from both clinical trials along with case series and reports regarding the methods and utility of quadratus lumborum blocks for analgesia in patients receiving nephrectomy. For this literature review, we searched Pubmed, Embase, and Web of Science from their inception until 5/31/2020. Our search terms were as follows: “(nephrectomy OR laparoscopic nephrectomy) AND (QL block OR Quadratus Lumborum block OR QL OR TQL OR Thoracolumbar fascia block).” We analyzed all relevant clinical trials for quality using the Jadad scale. Our search yielded a total of 30 articles, 23 of which we ultimately reviewed for this manuscript. The qualitative sum of these data show that patients receiving quadratus lumborum block for nephrectomies have reduced opioid requirements, reduced pain scores, and improved side-effects relative to other analgesic modalities like epidurals. Based on these findings, we conclude that the quadratus lumborum block is a useful analgesic for patients undergoing nephrectomy.

Guidelines for the safe clinical practice of peripheral nerve blocks in the adult patient

The Peripheral Nerve Block working group of the Belgian Association for Regional Anesthesia has revised and updated the “Clinical guidelines for the practice of peripheral nerve block in the adult” which were published in 2013.

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.

Resuscitation Following a Bupivacaine Injection for a Cervical Paravertebral Block

Background

Cardiac arrest related to nerve blockade using a local anaesthetic is a rare event. We report a case of bupivacaine severe cardiovascular toxicity following cervical paravertebral nerve block.

Case presentation

A 44-year-old female was admitted to Republican Vilnius University Hospital, with symptoms of sustained severe pain in her neck that radiated to both arms. Multiple cervical intervertebral hernias with spinal stenosis were confirmed by magnetic resonance imaging. Following infiltration of the subcutaneous tissue with a 0.5 % bupivacaine solution, an 18-gauge spinal needle was used to perform the paravertebral block at the C6 level. Bupivacaine was injected in incremental doses to a total of 10 mL. Rapid loss of consciousness and cardiovascular collapse suggested a neuraxial injection of bupivacaine. Long-lasting cardiopulmonary resuscitation, including chest compressions, defibrillation attempts for refractory ventricular fibrillation, medications, mechanical ventilation, and intravenous lipid emulsion infusion, was successful. No severe adverse outcomes other than acute kidney injury and chest pain related to prolonged chest compressions were documented.

Conclusions

This case report emphasizes the necessity of ensuring adequate safety precautions to avoid local anaesthetic systemic toxicity. Lipid emulsion preparations should be available in all hospital settings where local anaesthetics are used for regional anaesthesia or pain management.

A Review of Regional Anesthesia in Infants

Regional anesthesia provides effective anesthesia and pain relief in infants with age-specific data attesting to safety and efficacy. Regional anesthesia decreases exposure to opioids and general anesthetic agents and associated adverse drug effects, suppresses the stress response, and provides better hemodynamic stability compared to general anesthesia. Regional anesthesia can prevent long-term behavioral responses to pain. As a result, the overall number and variety of nerve blocks being used in infants is increasing. While neuraxial blocks are the most common blocks performed in infants, the introduction of ultrasound imaging and a better safety profile has advanced the use of peripheral nerve blocks. Infant-specific pharmacokinetic and pharmacodynamic data of local anesthetic medications are reviewed including risk factors for the accumulation of high serum levels of unbound, pharmacologically active drug. Bupivacaine accumulates with continuous infusion and 2-chloroprocaine can be used as an alternative. Local anesthetic systemic toxicity has the highest incidence in infants less than 6 months of age and is associated with bolus dosing and penile nerve blocks. Local anesthetic toxicity is treated by securing the airway, suppression of seizure activity and implementation of cardiopulmonary resuscitation. Administration of intralipid (intravenous lipid emulsion) is initiated at the first sign of toxicity. A high level of expertise in regional anesthesia is needed when treating infants due to their unique development.

A review of peripheral nerve blocks for cesarean delivery analgesia

Peripheral nerve blocks have a unique role in postcesarean delivery multimodal analgesia regimens. In this review article, options for peripheral nerve blocks for cesarean delivery analgesia will be reviewed, specifically paravertebral, transversus abdominis plane, quadratus lumborum, iliohypogastric and ilioinguinal, erector spinae, and continuous wound infiltration blocks. Anatomy, existing literature evidence, and specific areas in need of future research will be assessed. Considerations for local anesthetic toxicity, and for informed consent for these modalities in the context of emergency cesarean deliveries, will be presented.

Lipid emulsion therapy of local anesthetic systemic toxicity due to dental anesthesia

Local anesthetic systemic toxicity (LAST) refers to the complication affecting the central nervous system (CNS) and cardiovascular system (CVS) due to the overdose of local anesthesia. Its reported prevalence is 0.27/1000, and the representative symptoms range from dizziness to unconsciousness in the CNS and from arrhythmias to cardiac arrest in the CVS. Predisposing factors of LAST include extremes of age, pregnancy, renal disease, cardiac disease, hepatic dysfunction, and drug-associated factors. To prevent the LAST, it is necessary to recognize the risk factors for each patient, choose a safe drug and dose of local anesthesia, use vasoconstrictor , confirm aspiration and use incremental injection techniques. According to the treatment guidelines for LAST, immediate application of lipid emulsion plays an important role. Although lipid emulsion is commonly used for parenteral nutrition, it has recently been widely used as a non-specific antidote for various types of drug toxicity, such as LAST treatment. According to the recently published guidelines, 20% lipid emulsion is to be intravenously injected at 1.5 mL/kg. After bolus injection, 15 mL/kg/h of lipid emulsion is to be continuously injected for LAST. However, caution must be observed for >1000 mL of injection, which is the maximum dose. We reviewed the incidence, mechanism, prevention, and treatment guidelines, and a serious complication of LAST occurring due to dental anesthesia. Furthermore, we introduced lipid emulsion that has recently been in the spotlight as the therapeutic strategy for LAST.

Successful intralipid-emulsion treatment of local anesthetic systemic toxicity following ultrasound-guided brachial plexus block: case report

Background

Local anesthetic systemic toxicity (LAST) is a life-threatening complication that may follow application of LAs through various routes. Despite increasing usage of LA techniques in a large number of health-care settings, contemporary awareness of LAST and understanding of its management are inadequate.

Case presentation

We report two cases who suffered LAST following brachial plexus block for surgery on the upper extremity. The first patient received an ultrasound-guided supraclavicular block with 300 mg lidocaine (6 mg/kg) and 50 mg ropivacaine (1 mg/kg) in 25 mL without epinephrine, and the second patient received an ultrasound guided interscalene block with 200 mg lidocaine (4.5 mg/kg) and 45 mg ropivacaine (1 mg/kg) supplemented with epinephrine 1:200,000. Both patients presented with symptoms of central nervous and respiratory system depression, the first roughly 10 minutes after injection, and the second immediately after withdrawal of the needle. In both cases, thorough recovery was obtained using lipid-emulsion therapy.

Conclusion

The complication of LAST following ultrasound-guided brachial plexus block could be treated successfully applying the American Society of Regional Anesthesia and Pain Medicineprotocol of intravenous administration of lipid emulsion.

LOCAL ANESTHETICS AND STEROIDS: CONTRAINDICATIONS AND COMPLICATIONS - CLINICAL UPDATE

The objective of this clinical update, based on recently published literature, was to discuss incidence and characteristics of the most relevant clinical adverse effects associated with local anesthetic and steroid use in regional anesthesia and treatment of acute or chronic pain. A comprehensive review of the English-language medical literature search utilizing PubMed, Ovid Medline® and Google Scholar from 2015 to 2018 was performed. This narrative review provides anesthesia practitioners with updated evidences on complications and contraindications of local anesthetic and steroid use with emphasis on current points of view regarding prevention, early diagnosis and treatment of adverse events.

In vitro and in vivo quantification of chloroprocaine release from an implantable device in a piglet postoperative pain model

Background

The pharmacokinetic properties and clinical advantages of the local anesthetic chloroprocaine are well known. Here, we studied the pharmacokinetic profile of a new hydrogel device loaded with chloroprocaine to investigate the potential advantages of this new strategy for postoperative pain (POP) relief.

Materials and methods

We performed both in vitro and in vivo analyses by considering plasma samples of four piglets receiving slow-release chloroprocaine. To quantify chloroprocaine and its inactive metabolite 4-amino-2-chlorobenzoic acid (ACBA), a HPLC–tandem mass spectrometry (HPLC-MS/MS) analytical method was used. Serial blood samples were collected over 108 hours, according to the exposure time to the device.

Results

Chloroprocaine was consistently found to be below the lower limit of quantification, even though a well-defined peak was observed in every chromatogram at an unexpected retention time. Concerning ACBA, we found detectable plasma concentrations between T₀ and T_12h, with a maximum plasma concentration (C_max) observed 3 hours after the device application. In the in vitro analyses, the nanogel remained in contact with plasma at 37°C for 90 minutes, 3 hours, 1 day, and 7 days. Chloroprocaine C_max was identified 1 day following exposure and C_min after 7 days, respectively. Additionally, ACBA reached the C_max following 7 days of exposure.

Conclusion

A thorough review of the literature indicates that this is the first study analyzing both in vivo and in vitro pharmacokinetic profiles of a chloroprocaine hydrogel device and is considered as a pilot study on the feasibility of including this approach to the management of POP.

Local anesthetic systemic toxicity: current perspectives

Local anesthetic systemic toxicity (LAST) is a life-threatening adverse event that may occur after the administration of local anesthetic drugs through a variety of routes. Increasing use of local anesthetic techniques in various healthcare settings makes contemporary understanding of LAST highly relevant. Recent data have demonstrated that the underlying mechanisms of LAST are multifactorial, with diverse cellular effects in the central nervous system and cardiovascular system. Although neurological presentation is most common, LAST often presents atypically, and one-fifth of the reported cases present with isolated cardiovascular disturbance. There are several risk factors that are associated with the drug used and the administration technique. LAST can be mitigated by targeting the modifiable risk factors, including the use of ultrasound for regional anesthetic techniques and restricting drug dosage. There have been significant developments in our understanding of LAST treatment. Key advances include early administration of lipid emulsion therapy, prompt seizure management, and careful selection of cardiovascular supportive pharmacotherapy. Cognizance of the mechanisms, risk factors, prevention, and therapy of LAST is vital to any practitioner using local anesthetic drugs in their clinical practice.