Local anesthetic systemic toxicity: Continuing Professional Development

A review of local anesthetic-induced heart toxicity using human induced pluripotent stem cell-derived cardiomyocytes

Local anesthetic (LA) cardiotoxicity is one of the main health problems in anesthesiology and pain management. This study reviewed the reported LA-induced cardiac toxicity types, risk factors, management, and mechanisms, with attention to the use of human induced pluripotent stem cell-derived cardiomyocytes (hiPSC-CMs) in heart toxicity research. Important scientific databases were searched to find relevant articles. We briefly assessed the reported cardiotoxic effects of different types of LA drugs, including ester- and amide-linked LA agents. Furthermore, cardiotoxic effects and clinical manifestations, strategies for preventing and managing LA-induced cardiotoxic effects, pharmacokinetics, pharmacodynamics, and sodium channel dynamics regarding individual variability and genetic influences were discussed in this review. The applications and importance of hiPSC-CMs cellular model for evaluating the cardiotoxic effects of LA drugs were discussed in detail. This review also explored hiPSC-CMs' potential in risk assessment, drug screening, and developing targeted therapies. The main mechanisms underlying LA-induced cardiotoxicity included perturbation in sodium channels, ROS production, and disorders in the immune system response due to the presence of LA drugs. Furthermore, drug-specific characteristics including pharmacokinetics and pharmacodynamics are important determinants after LA drug injection. In addition, individual patient factors such as age, comorbidities, and genetic variability emphasize the need for a personalized approach to mitigate risks and enhance patient safety. The strategies outlined for the prevention and management of LA cardiotoxicity underscore the importance of careful dosing, continuous monitoring, and the immediate availability of resuscitation equipment. This comprehensive review can be used to guide future investigations into better understanding LA cardiac toxicities and improving patient safety.

Regional Anesthesia Complications and Contraindications

Regional anesthesia has a strong role in minimizing post-operative pain, decreasing narcotic use and PONV, and, therefore, speeding discharge times. However, as with any procedure, regional anesthesia has both benefits and risks. It is important to identify the complications and contraindications related to regional anesthesia, which patient populations are at highest risk, and how to mitigate those risks to the greatest extent possible. Overall, significant complications secondary to regional anesthesia remain low. While a variety of different regional anesthesia techniques exist, complications tend to fall within 4 broad categories: block failure, bleeding/hematoma, neurological injury, and local anesthetic toxicity.

Local Anesthetic Systemic Toxicity Joint Management in the Prehospital Environment: A Case Report

Local anesthetic systemic toxicity (LAST) is a potentially life-threatening complication that may occur after local anesthetic injection. After reaching the systemic circulation, cardiovascular and central nervous system derangements may appear, with potentially fatal complications if left untreated. The pillars for LAST treatment are advanced life support measures, airway and seizure management, and a 20% lipid emulsion intravenous administration. When occurring in the prehospital setting, LAST is difficult to recognize, mostly because of its features overlapping with other acute conditions. Prompt treatment is also challenging because lipid emulsion may not be routinely carried on emergency vehicles. This article reports a case of LAST occurring in a dental ambulatory located in a remote location within the Italian Alps in which effective communication among different components of the same regional health care system (dispatch center, prehospital teams, and hospital network) led to fast lipid emulsion retrieval en route and on-site toxicity resolution. This case can inspire future operational changes, such as antidote networks available to prehospital emergency medicine crews, avoiding unnecessary deployment of antidotes on ambulances or helicopters, which is difficult to preserve without increasing management costs. However, to be established, such a network would need protocols to facilitate antidote retrieval, training focused on toxidromes recognition, and improved communication skills among different professionals involved in prehospital emergency medicine.

Intravenous lipid emulsion for local anaesthetic systemic toxicity in pregnant women: a scoping review

BACKGROUND

Local anaesthetic systemic toxicity (LAST) is a rare but life-threatening complication that can occur after local anaesthetic administration. Various clinical guidelines recommend an intravenous lipid emulsion as a treatment for local anaesthetic-induced cardiac arrest. However, its therapeutic application in pregnant patients has not yet been established. This scoping review aims to systematically identify and map the evidence on the efficacy and safety of intravenous lipid emulsion for treating LAST during pregnancy.

METHOD

We searched electronic databases (Medline, Embase and Cochrane Central Register Controlled Trials) and a clinical registry (lipidrescue.org) from inception to Sep 30, 2022. No restriction was placed on the year of publication or the language. We included any study design containing primary data on obstetric patients with signs and symptoms of LAST.

RESULTS

After eliminating duplicates, we screened 8,370 titles and abstracts, retrieving 41 full-text articles. We identified 22 women who developed LAST during pregnancy and childbirth, all presented as case reports or series. The most frequent causes of LAST were drug overdose and intravascular migration of the epidural catheter followed by wrong-route drug errors (i.e. intravenous anaesthetic administration). Of the 15 women who received lipid emulsions, all survived and none sustained lasting neurological or cardiovascular damage related to LAST. No adverse events or side effects following intravenous lipid emulsion administration were reported in mothers or neonates. Five of the seven women who did not receive lipid emulsions survived; however, the other two died.

CONCLUSION

Studies on the efficacy and safety of lipids in pregnancy are scarce. Further studies with appropriate comparison groups are needed to provide more robust evidence. It will also be necessary to accumulate data-including adverse events-to enable clinicians to conduct risk-benefit analyses of lipids and to facilitate evidence-based decision-making for clinical practice.

Local anaesthetics risks perception: A web-based survey

Background

The use of local anaesthetics (LAs) is usually associated with few adverse effects, but local anaesthetic systemic toxicity (LAST) can result in serious harm and even death. However, practitioner awareness regarding this risk has been little studied.

Methods

This was a closed, web-based study carried out at two Swiss university hospitals using a fully automated questionnaire. The main objective was to evaluate LAST awareness and LA use among various medical practitioners. The secondary objective was to determine whether these physicians felt that a tool designed to compute maximum safe LA doses should be developed.

Results

The overall participation rate was 40.2 % and was higher among anaesthesiologists (154/249, 61.8 % vs 159/530, 30.0 %; P < .001). Anaesthesiologists identified the risk of LAST and the systems involved more frequently than non-anaesthesiologists (85.1 % vs 43.4 %, P < .001). After adjusting for years of clinical experience, age, country of diploma, frequency of LA use, clinical position and being an anaesthesiologist, the only significant associations were this latter factor (P < .001) and clinical position (P = .016 for fellows and P = .046 for consultants, respectively). Most respondents supported the development of a tool designed to compute maximum safe LA doses (251/313, 80.2 %) and particularly of a mobile app (190/251, 75.7 %).

Conclusions

LAST awareness is limited among practitioners who use LAs on a regular basis. Educational interventions should be created, and tools designed to help calculate maximum safe LA doses developed. The actual frequency of unsafe LA doses administration would also deserve further study.

A Case Study and Literature Review of Local Anesthetic Systemic Toxicity During Placement of a Dual-chamber Pacemaker

Local anesthetics are commonly deployed for a variety of medical procedures across many disciplines. Systemic toxicity is rarely seen in clinical practice, and quick recognition and how to manage this syndrome are crucial. The development of systemic toxicity is influenced by the site of administration, the type of anesthetic used, and the total dose administered. Local anesthetic systemic toxicity (LAST) syndrome is used as a diagnosis to encompass the cardiovascular and pulmonary adverse effects associated with the intradermal and subcutaneous use of local anesthetics-in our case, lidocaine. We present a case of a 37-year-old man who experienced dysarthria, bilateral arm shaking, and sinus tachycardia following the administration of 70 mL of lidocaine 2% during surgery for dual-chamber pacemaker placement. While some form of allergic reaction remained a possibility, the strongest clinical correlation and diagnosis were attributed to LAST.

Local anaesthetic systemic toxicity complicating intraoperative intercostal nerve blocks: What do clinicians need to know to prevent similar occurrence?

Local anaesthetic systemic toxicity is a life-threatening adverse event that may occur after administration of local anaesthetics through a variety of routes. Local anaesthetic systemic toxicity is always a potential complication and may occur with all local anaesthetics and in any route of administration. Local anaesthetic systemic toxicity primarily affects the central nervous system and the cardiovascular system and may be fatal. The following is a case of local anaesthetic systemic toxicity complicating surgeon-performed intraoperative intercostal nerve blocks at multiple levels, with a mixture of liposomal bupivacaine and bupivacaine hydrochloride in a patient who underwent video-assisted segmental lung resection for lung cancer under general anaesthesia. Local anaesthetic systemic toxicity presented with seizures and hypotension. The patient was successfully managed and fully recovered. This case illustrates the importance of awareness regarding the prevention, diagnosis and treatment of local anaesthetic systemic toxicity among medical professionals who administer local anaesthetics.

Safety of local anesthetics in cervical nerve root injections: a narrative review

Severe neurological adverse events have been reported after fluoroscopically guided cervical nerve root injections. Particulate corticosteroids inadvertently injected intraarterially and iatrogenic vertebral artery trauma have been implicated in these outcomes. This has raised concern for the potential consequences of including local anesthetic with these injections. As a result, some providers have now discontinued the routine administration of local anesthetic with corticosteroid when performing cervical nerve root injections. At present, there is no consensus regarding whether the use of local anesthetic in this context is safe. Here, the current literature is synthesized into a narrative review aiming to clarify current perspectives of the safety of local anesthetics in cervical nerve root injections.

Chronological changes in plasma levobupivacaine concentrations after bilateral modified thoracoabdominal nerve block through perichondrial approach

The local anesthetic (LA) systemic toxicity of trunk blocks is a major concern. Recently, modified thoracoabdominal nerve block through perichondrial approach (M-TAPA) has attracted attention; however, plasma LA level is unknown. We tested whether the peak plasma LA concentration following M-TAPA, using 25 mL of 0.25% levobupivacaine mixed with epinephrine on each side, would be below the toxic level (2.6 μg/mL). We recruited 10 patients undergoing abdominal surgery with planned M-TAPA between November 2021 and February 2022. In all patients, 25 mL of 0.25% levobupivacaine mixed with 1:200,000 epinephrine was administered on each side. Blood samples were obtained at 10, 20, 30, 45, 60, and 120 min after the block. The highest individual peak and the mean peak plasma LA concentrations were 1.03 and 0.73 μg/mL, respectively. We could not capture the peak in five patients; however, the highest concentrations in all patients were significantly lower than the toxic level. A negative correlation between the peak level and body weight was observed. Our results indicated that the plasma LA concentration following M-TAPA using total of 50 mL of 0.25% levobupivacaine with epinephrine remains below the toxic level. Further research is required due to the small sample size of this study.Trial registry number: UMIN000045406.

Liberal use of local anaesthetic and the risk of toxicity in elective arthroplasties at a tertiary teaching hospital

Background

Local anaesthetic systemic toxicity (LAST) is a life-threatening potential complication that may follow the administration of local anaesthetic (LA) drugs, and is cumulative across the drug class. Local anaesthetics are commonly administered via different routes for elective orthopaedic procedures – both by anaesthetists and surgeons. We hypothesized that total doses of LA may be routinely encroaching upon toxicity.

Methods

All total hip or knee arthroplasties (THAs and TKAs) performed within a 3 month period at the John Hunter Hospital (tertiary referral centre and teaching hospital) were audited to assess total administration of LA. Demographics, surgical characteristics, use of general anaesthesia or sedation, and use of local anaesthetic via any route of administration was recorded. For each patient, a weight-based theoretical maximum safe dose was calculated and compared against the dose they received. Data is presented as mean ± SD, percentages. Statistical significance was determined at p < 0.05.

Results

130 THAs and TKAs were identified within the audit period. 52 patients exceeded their drug-class theoretical maximum safe dose. 49 patients exceeded their weight-based maximum dose for a single LA agent, in all cases ropivacaine. Non-obese individuals receive significantly higher mean dose than obese individuals (119.4% [98.6–140.3] vs 78.82% [65.95–91.69], p = 0.001). No LAST events were identified.

Conclusions

Patients who received elective total hip or knee arthroplasties were exposed to concerningly high total doses of local anaesthetic, suggesting that greater awareness of the additive toxicity of drugs within this class is required.

Analgesic benefits of the quadratus lumborum block in total hip arthroplasty: a systematic review and meta-analysis

The quadratus lumborum block (QLB) is reported to reduce pain and improve function following total hip arthroplasty; however, randomised controlled trials evaluating the benefits of adding this block to general or spinal anaesthesia in this population are conflicting. We performed a systematic review seeking randomised controlled trials investigating QLB benefits for total hip arthroplasty, stratifying comparisons regarding the addition of QLB to either general or spinal anaesthesia. The primary outcome was 24-h area under the curve (AUC) pain score. Pain scores were interpreted in the context of a population-specific minimal clinically important difference of 1.86 cm on a 10-cm visual analogue scale, or an AUC pain score of 5.58 cm.h. Secondary outcomes included analgesic consumption, functional recovery and opioid-related side-effects. In all, 18 trials (1318 patients) were included. Adding QLB to general or spinal anaesthesia improved 24-h AUC rest pain scores by a mean difference (95%CI) of -3.56 cm.h (-6.70 to -0.42; p = 0.034) and - 4.19 cm.h (-7.20 to -1.18; p = 0.014), respectively. These improvements failed to reach the pre-determined minimal clinically important difference, as did the reduction in analgesic consumption. Quadratus lumborum block improved functional recovery for general, but not spinal, anaesthesia. Opioid-related side-effects were reduced with QLB regardless of anaesthetic modality. Low-to-moderate quality evidence suggests that the extent to which adding QLB to either general or spinal anaesthesia reduces postoperative pain and opioid consumption after total hip arthroplasty is statistically significant but may be clinically unimportant for most patients. However, adding QLB to general anaesthesia might enhance functional recovery. Taken together, our findings do not support the routine use of QLB as part of multimodal analgesic regimens for total hip arthroplasty.

Local anesthetic systemic toxicity: A narrative review for emergency clinicians

INTRODUCTION

Emergency clinicians utilize local anesthetics for a variety of procedures in the emergency department (ED) setting. Local anesthetic systemic toxicity (LAST) is a potentially deadly complication.

OBJECTIVE

This narrative review provides emergency clinicians with the most current evidence regarding the pathophysiology, evaluation, and management of patients with LAST.

DISCUSSION

LAST is an uncommon but potentially life-threatening complication of local anesthetic use that may be encountered in the ED. Patients at extremes of age or with organ dysfunction are at higher risk. Inadvertent intra-arterial or intravenous injection, as well as repeated doses and higher doses of local anesthetics are associated with greater risk of developing LAST. Neurologic and cardiovascular manifestations can occur. Early recognition and intervention, including supportive care and intravenous lipid emulsion 20%, are the mainstays of treatment. Using ultrasound guidance, aspirating prior to injection, and utilizing the minimal local anesthetic dose needed are techniques that can reduce the risk of LAST.

CONCLUSIONS

This focused review provides an update for the emergency clinician to manage patients with LAST.

PEC block versus local anesthetic infiltration in breast implant augmentation surgery: a retrospective study

INTRODUCTION

Pectoral plane (PEC) blocks are routinely used in analgesia for patients undergoing dual-plane breast augmentation with implants. Local anesthetic infiltration (LAI) is a simple alternative technique with the same aim. We evaluated both techniques.

MM

In this single-center retrospective study, patients received PEC block (ropivacaine 0.2%, 10 ml PEC I, 20 ml PEC II) or LAI. The primary outcome measure was pain, according to the visual analog scale (VAS), at 24h post-surgery. Secondary outcomes included the measure of pain at 1, 2, 6, and 12 hours post-surgery, total opioid consumption at 24h, and opioid side effects.

RESULTS

81 were finally recruited: 37 in the PEC group and 44 in the LAI group. Patient characteristics were comparable between the two groups. At 24h post-surgery, the LAI group showed a decrease in pain, with a VAS score of 0.7 vs 1.5 in the PEC group (p = 0.007). There was no difference in VAS between the two groups at 1, 2, 6, or 12 hours post-surgery. The duration of anesthesia was increased in the PEC group with 153 minutes vs 120 minutes in the LAI group (p < 0.001). There was no difference in rescue morphine consumption between the two groups.

CONCLUSIONS

We found that LAI had a superior analgesic effect at 24h after surgery for dual-plane breast implant augmentation compared with PEC block. These findings are a good indication that the LAI technique is at least as effective as PEC block while being safe, fast, and easy to use.

A Case of Late-Onset Local Anesthetic Toxicity Observed as Seizure Activity

Most of the local anesthetic toxicity cases develop within the first five minutes of peripheral block administration. Late local anesthetic toxicity has been rarely reported in the literature. However, it is an important life-threatening problem that can lead to seizures, hemodynamic collapse, and cardiac arrest if it is ignored and not considered. Here we present the case of an 18-year-old male patient who had ultrasonography-guided infraclavicular brachial plexus block administration with a 30 mL local anesthetic. The patient had convulsions 210 minutes after the block administration and was treated with intravenous diazepam. Intraoperative and postoperative courses were uneventful. He had no neurologic signs or symptoms afterward. All laboratory tests and radiologic investigation tests were normal. This report demonstrates that late local anesthetic toxicity is still possible after several hours of the uneventful peripheral neural blockade, although it is rarely reported.

Retrograde Approach to Maxillary Nerve Block: An Alternative in Orofacial Surgeries in Horses

Simple Summary

Maxillary nerve (MN) desensitization can improve quality and safety of orofacial surgeries in horses, especially when a standing procedure is elected. The purpose of this retrospective study is to report results from 15 horses undergoing orofacial surgery which received an MN block with the retrograde approach within the infraorbital canal. The same technique was used in horses scheduled for orofacial surgeries and grouped as requiring general anesthesia or standing analgo-sedation. From the retrieved anesthetic records, regardless of the group, clinical and physiological parameters continuously monitored during surgery were stable, and none of the horses showed complications during or after the block. These results confirm the feasibility of this loco-regional anesthetic technique as a valid approach to the MN without risk of damaging periorbital structures, which is reported with traditional techniques. Evident landmarks for this approach and limited chances to injure vital structures enclosed within the infraorbital canal make the operator experience less relevant than the ability required to block the MN according to approaches, which currently aim at the pterygopalatine fossa. This substantiates the retrograde approach to block the MN is safe and easy to perform in horses undergoing orofacial surgeries at regions where this nerve provides sensory innervation.

Abstract

The aim of this study was to retrospectively report outcomes resulting from the approach to the maxillary nerve block (MNB) through the infraorbital canal, in terms of needles selection, drawbacks or side effects during or after block execution, and analgesic efficacy leading to clinical and cardiovascular stability during surgery. Anesthetic records of 15 horses undergoing orofacial surgery in standing analgo-sedation (STA, n = 6) and in general anesthesia (GEN, n = 9) were retrieved and analyzed. Horses in group STA required surgery for dental extraction, nasal polyp resection and maxillary/frontal sinusitis. Horses in group GEN underwent surgery for fronto-maxillary, nasal and dental diseases. Size 19 and 20 G Tuohy needles were used in adult horses weighing 350–600 kg, while size 21 and 22 G were used in younger horses or ponies. None of the horses in both groups showed complications related to the block and physiological parameters were stable and within normal ranges during surgery; overall, an adequate anesthetic/sedation depth was achieved. Our results confirm the in vivo applicability of the MNB approached within the infraorbital canal, which had been described only on cadaveric specimens. The retrograde technique resulted in a valid and easy approach to the maxillary nerve that avoids damage to periorbital structures and side effects reported with traditional techniques.

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.

Osthole-Mediated Inhibition of Neurotoxicity Induced by Ropivacaine via Amplification of the Cyclic Adenosine Monophosphate Signaling Pathway

Background

Ropivacaine is widely used for clinical anesthesia and postoperative analgesia. However, the neurotoxicity induced by ropivacaine in a concentration- and duration-dependent manner, and it is difficult to prevent neurotoxicity. Osthole inhibits phosphodiesterase-4 activity by binding to its catalytic site to prevent cAMP hydrolysis. The aim of this present study is to explore the precise molecular mechanism of osthole-mediated inhibition of neurotoxicity induced by ropivacaine.

Methods:

SH-SY5Y cell viability and apoptosis were measured in different concentration and duration. Protein concentration was determined in each signaling pathway. The molecular mechanism of osthole-mediated inhibition of ropivacaine-caused neurotoxicity was evaluated.

Results

The study demonstrated that osthole inhibits SH-SY5Y cells neurotoxicity in a duration- and concentration-dependent manner. Moreover, ropivacaine significantly increased the expression of caspase-3 by promoting the phosphorylation of p38. Osthole-induced upregulation of cAMP activated cAMP-dependent signaling pathway, sequentially leading to elevated cyclic nucleotide response element-binding protein levels, which inhibits P38-dependent signaling and decreases apoptosis of SH-SY5Y.

Conclusions

This study display the evidence confirmed the molecular mechanism by which osthole amplification of cAMP-dependent signaling pathway, and overexpression of cyclic nucleotide response element-binding protein inhibits P38-dependent signaling and decreases ropivacaine-induced SH-SY5Y apoptosis.

Regional Anesthesia Complications and Contraindications

Regional anesthesia has a strong role in minimizing post-operative pain, decreasing narcotic use and PONV, and, therefore, speeding discharge times. However, as with any procedure, regional anesthesia has both benefits and risks. It is important to identify the complications and contraindications related to regional anesthesia, which patient populations are at highest risk, and how to mitigate those risks to the greatest extent possible. Overall, significant complications secondary to regional anesthesia remain low. While a variety of different regional anesthesia techniques exist, complications tend to fall within 4 broad categories: block failure, bleeding/hematoma, neurological injury, and local anesthetic toxicity.

Local Anesthetic Systemic Toxicity during Labor, Birth, and Immediate Postpartum: Clinical Review

ABSTRACT

Local anesthetic systemic toxicity (LAST) is a life-threatening event caused by elevated local anesthetic plasma concentration. It is often unrecognized or misdiagnosed. Peripartum women are at increased risk for toxicity due to pregnancy-related physiological changes. Rising serum drug levels can cause cellular level impairment of mitochondria and voltage-gated ion channels leading to a cascade of symptoms that can end in cardiac arrest. Local anesthetic systemic toxicity can mimic other maternal pathologies but may be considered if local anesthetics have been used. Published treatment guidelines for this event include lipid emulsion which is approved for use in pregnant women. We review LAST in the maternity care setting, published treatment protocols, management of maternity patients with toxicity, and recommendations to increase awareness among maternity care clinicians for this medical emergency.

Mechanisms of action of fascial plane blocks: a narrative review

BACKGROUND

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

OBJECTIVES

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

FINDINGS

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

CONCLUSION

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

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.

The efficacy of ultrasound-guided stellate ganglion block in alleviating postoperative pain and ventricular arrhythmias and its application prospects

Stellate ganglion block (SGB) has been applied in clinic for almost a century as a therapeutic procedure to alleviate pain-related syndromes and vascular deficits in the upper extremities. A great number of causative side effects and complications due to technological insufficiency and anatomical variations called for the popularity of ultrasound-guided SGB which has made tremendous contribution for clinical diagnosis and therapy, primarily in postoperative pain and cardiac and vascular disorders. This work was aimed at systematically summarizing the current clinical application of ultrasound-guided SGB and putting forward the potential prospective application in future. By searching ultrasound-guided SGB-related works on PubMed database, we mainly elucidated the analgesic effect of preoperative SGB in patients undergoing surgical procedures and substantial reduction in patients with ventricular arrhythmias. The volume of local anesthetics used in ultrasound-guided SGB has been diminished in the recent few years' investigations and successful operation of ultrasound-guided SGB could be achieved with minimal safe volume of local anesthetics. This invasive and safe procedure shows vast potential for future development in clinical treatment for autonomic nervous system and autoimmune disorders. We also put forward hypothesis that ultrasound-guided SGB could be applied combined with controlled hypotension to reduce the intraoperative complications in orthopedic surgery such as insufficiency of cerebral blood flow and reflexive tachycardia. Thus, it is of vital essence to improve the professional skills of physicians for the high rate of success and explore more effective measures which could enhance therapeutic effects when combined with ultrasound-guided SGB in alleviating misery of patients.

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.

Updates in our understanding of local anaesthetic systemic toxicity: a narrative review

Despite advances in clinical practice, local anaesthetic systemic toxicity continues to occur with the therapeutic use of local anaesthesia. Patterns of presentation have evolved over recent years due in part to the increasing use of ultrasound which has been demonstrated to reduce risk. Onset of toxicity is increasingly delayed, a greater proportion of clinical reports are secondary to fascial plane blocks, and cases are increasing where non-anaesthetist providers are involved. The evolving clinical context presents a challenge for diagnosis and requires education of all physicians, nurses and allied health professionals about these changing patterns and risks. This review discusses: mechanisms; prevention; diagnosis; and treatment of local anaesthetic systemic toxicity. The local anaesthetic and dose used, site of injection and block conduct and technique are all important determinants of local anaesthetic systemic toxicity, as are various patient factors. Risk mitigation is discussed including the care of at-risk groups, such as: those at the extremes of age; patients with cardiac, hepatic and specific metabolic diseases; and those who are pregnant. Advances in the changing clinical landscape with novel applications and settings for the use of local anaesthesia are also described. Finally, we signpost future directions to potentially improve the management of local anaesthetic systemic toxicity. The utility of local anaesthetics remains unquestionable in clinical practice, and thus maximising the safe and appropriate use of these drugs should translate to improvements in patient care.

Neurotoxicity secondary to local tetracaine use

INTRODUCTION

Systemic reactions from local tetracaine use are often an anomaly - not only is tetracaine short-acting and quickly metabolized by the pseudocholinesterase system leading to very limited systemic uptake, but most adverse reactions are usually associated with dental or spinal anesthesia. Furthermore, reactions to local anesthetics manifest in standard allergy-type reactions. When local anesthetics lead to nervous or cardiac system abnormalities, it is termed a local anesthetic systemic toxicity - an event with an incidence currently estimated to be 0.03%.

CASE PRESENTATION

We present a case of a 56-year-old female who experienced a systemic reaction to tetracaine 1% while undergoing a fine needle biopsy of a thyroid nodule. The patient had previous allergic reactions to lidocaine. Upon conclusion of the procedure, the patient began convulsing and became rigid and non-verbal. She was able to move all extremities, had no respiratory distress, no swelling, hives, or redness, and was swallowing without difficulty. After about 5 min, the patient began to improve and experienced reversal of all previous symptoms. Her physical exam and labs were otherwise normal, she returned to her baseline functioning, and was discharged without any medical interventions.

DISCUSSION

This case illustrates a case of LAST in a patient with previous Lidocaine allergy without any other obvious risk factors. There have been no cases of cross-reaction between lidocaine and tetracaine so it explores the possibility of patients having cross reaction to those two different kinds of local anesthetic.

Difficult Airway Society guidelines for awake tracheal intubation (ATI) in adults

Awake tracheal intubation has a high success rate and a favourable safety profile but is underused in cases of anticipated difficult airway management. These guidelines are a comprehensive document to support decision making, preparation and practical performance of awake tracheal intubation. We performed a systematic review of the literature seeking all of the available evidence for each element of awake tracheal intubation in order to make recommendations. In the absence of high‐quality evidence, expert consensus and a Delphi study were used to formulate recommendations. We highlight key areas of awake tracheal intubation in which specific recommendations were made, which included: indications; procedural setup; checklists; oxygenation; airway topicalisation; sedation; verification of tracheal tube position; complications; management of unsuccessful awake tracheal intubation; post‐tracheal intubation management; consent; and training. We recognise that there are a range of techniques and regimens that may be effective and one such example technique is included. Breaking down the key practical elements of awake tracheal intubation into sedation, topicalisation, oxygenation and performance might help practitioners to plan, perform and address complications. These guidelines aim to support clinical practice and help lower the threshold for performing awake tracheal intubation when indicated.

Tonic-clonic seizure during the ultrasound-guided stellate ganglion block because of an injection into an unrecognized variant vertebral artery: A case report

RATIONALE

Recent years have witnessed a marked improvement in the safety and accuracy of nerve blocks with the help of ultrasound and other visualization technologies. This study reports a challenging case of a severe complication during the ultrasound-guided stellate ganglion block.

PATIENT CONCERNS

A 28-year-old male patient with refractory migraine complained episodic pulsatile pain with photophobia, haphalgesia of the scalp for 3 years.

INTERVENTIONS

Ultrasound-guided stellate ganglion block with 4 ml of 1% lidocaine was administrated.

OUTCOMES

A sudden loss of consciousness and tonic-clonic seizure was occurred after negative aspiration and test dose. Further sonographic examination revealed a variation in the left vertebral artery, which remained unrecognized during the needle insertion because of its sliding ability under the differential pressure applied by the probe.

LESSONS

Inadvertent intra-arterial injection of a local anesthetic agent could be minimized under the ultrasound guidance with various protective strategies, including the determination of any prior variation, optimizing the block route, maintaining a constant probe pressure, and using saline for the test dosage. This case resulted in the implementation of new protocols of the ultrasound-guided stellate ganglion block in our department.

Bilateral single-injection erector spinae plane block versus intrathecal morphine for postoperative analgesia in living donor laparoscopic hepatectomy: a randomized non-inferiority trial

BACKGROUND

Intrathecal morphine (ITM) provides effective postoperative analgesia in living donor hepatectomy but has significant adverse effects. Studies support the efficacy of erector spinae plane (ESP) blocks in laparoscopic abdominal surgery; we therefore hypothesized that they would provide non-inferior postoperative analgesia compared with ITM and reduce postoperative nausea/vomiting and pruritus. We conducted a randomized, controlled, non-inferiority trial to compare the analgesic efficacy of ITM and bilateral single-injection ESP blocks in laparoscopic donor hepatectomy.

METHODS

Fifty-four donors were randomized to receive bilateral ESP blocks with 20 mL 0.5% ropivacaine (n=27) or 400 µg ITM (n=27). Primary outcome was resting pain score 24 hours postoperatively measured on an 11-point numeric rating scale. The prespecified non-inferiority limit was 1. Incidences of postoperative nausea/vomiting and pruritus were assessed.

RESULTS

The mean treatment difference (ESP-ITM) in the primary outcome was 1.2 (95% CI 0.7 to 1.8). The 95% CI upper limit exceeded the non-inferiority limit. Opioid consumption and all other pain measurements were similar between groups up to 72 hours postoperatively. The ESP group had significantly lower incidences of postoperative vomiting (p=0.002) and pruritus (p<0.001).

CONCLUSIONS

Bilateral single-injection ESP blocks resulted in higher resting pain scores 24 hours postoperatively compared with ITM and thus did not meet the study definition of non-inferiority. However, the pain intensity with ESP blocks was mild (mean pain scores <3/10) and associated with reduced incidence of postoperative vomiting and pruritus. It warrants further investigation as an analgesic option after laparoscopic living donor hepatectomy.

TRIAL REGISTRATION NUMBER

KCT0003191.

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.

Unconsciousness After Regional Anesthesia for Arteriovenous Fistula Revision in a Patient with End-stage Renal Disease

Chronic kidney disease can lead to different chronic complications. We describe a case where a patient with end-stage renal disease (ESRD) became unresponsive during transportation to the recovery room, following finishing an arteriovenous fistula revision. The patient had received supraclavicular block ninety minutes prior to the incident and surgery was finished under monitored anesthesia care (MAC). After five minutes of chest compression and intubation, monitoring showed normal sinus rhythm and the return of spontaneous circulation. The patient was transferred to the intensive care unit and extubated two days later while she was alert, oriented and hemodynamically stable. CT pulmonary angiogram showed no evidence of pulmonary emboli and echocardiogram did not show any further cardiac event comparing to preoperative status. Ruling out other differential diagnoses for patient's unconsciousness, we have discussed the possibility of neuraxial anesthesia after upper extremity block in this patient.

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.

Combined ultrasound and nerve stimulator-guided deep nerve block may decrease the rate of local anesthetics systemic toxicity: a randomized clinical trial

Background

Ultrasound guidance might decrease the incidence of local anesthetics systemic toxicity (LAST) for many peripheral nerve blocks compared with nerve stimulator guidance. However, it remains uncertain whether ultrasound guidance is superior to nerve stimulator guidance for deep nerve block of the lower extremity. This study was designed to investigate whether deep nerve block with ultrasound guidance would decrease the incidence of LAST compared with that with nerve stimulator guidance, and to identify associated risk factors of LAST.

Methods

Three hundred patients undergoing elective lower limb surgery and desiring lumbar plexus blocks (LPBs) and sciatic nerve blocks (SNBs) were enrolled in this study. The patients were randomly assigned to receive LPBs and SNBs with ultrasound guidance (group U), nerve stimulator guidance (group N) or dual guidance (group M). The primary outcome was the incidence of LAST. The secondary outcomes were the number of needle redirection, motor and sensory block onset and nerve distribution restoration time, as well as associated risk factors.

Results

There were 18 patients with LAST, including 12 in group U, 4 in group N and 2 in group M. By multiple comparisons among the three groups, we found that the incidence of LAST in group U (12%) was significantly higher than that in group N (4%)(P = 0.037) and group M(2%)(P = 0.006). The OR of LAST with hepatitis B (HBV) infection and the female sex was 3.352 (95% CI,1.233–9.108, P = 0.013) and 9.488 (95% CI,2.142–42.093, P = 0.0004), respectively.

Conclusions

Ultrasound guidance, HBV infection and the female sex were risk factors of LAST with LPBs and SNBs. For patients infected with HBV or female patients receiving LPBs and SNBs, we recommended that combined ultrasound and nerve stimulator guidance should be used to improve the safety.

Trial registration

This study was approved by the Ethical Committee of the First Affiliated Hospital of Army Medical University. The protocol was registered prospectively with the Chinese Clinical Trial Registry (ChiCTR-IOR-16008099) on March 15, 2016.

Quadratus Lumborum Block: Anatomical Concepts, Mechanisms, and Techniques

A review of anatomy, potential mechanisms of action, and techniques and summary of clinical evidence for quadratus lumborum block.

Ultrasound-guided Erector Spinae Plane Block: Indications, Complications, and Effects on Acute and Chronic Pain Based on a Single-center Experience

INTRODUCTION

Erector spinae plane block (ESPB) is a novel regional anesthesia technique used in postoperative pain and chronic neuropathic pain of the thoracoabdominal region. There are no previously published large case series. This retrospective review aimed to report the indications, levels of block, success of block and complications, and also to evaluate the effect of ESPB on postoperative/chronic pain.

METHODS

We retrospectively evaluated the charts and medical records of 182 patients who had ESPB in the last one year. All records were collected in the postoperative recovery room, ward, and pain unit.

RESULTS

ESPB performed at several different levels and for several different indications led to effective postoperative analgesia when part of a multimodal analgesia plan. Few complications were noted.

CONCLUSION

ESPB is an interfascial plane block with many indications. The possibility of complications must be considered.

Transversus abdominis plane block with liposomal bupivacaine for pain control after cesarean delivery: a retrospective chart review

Background

Adverse effects of opioid analgesics and potential for chronic use are limitations in the cesarean setting. Regional anesthesia using transversus abdominis plane (TAP) block post-cesarean delivery may improve analgesia and reduce opioid consumption. Effectiveness of TAP block using liposomal bupivacaine (LB) to reduce post-cesarean pain is unknown.

Methods

We performed a single-center retrospective chart review of patients aged ≥18 years who underwent cesarean delivery with a multimodal pain management protocol with or without TAP block with LB 266 mg. Assessments included postsurgical opioid consumption; area under the curve (AUC) of numeric rating scale pain scores from 0 to 3 days; proportion of opioid-free patients; discharge- and post-anesthesia care unit (PACU)-ready time; times to ambulation, solid food, and bowel movement; hospital length of stay (LOS); and adverse events (AEs). Data were analyzed in the total population and in first- and repeat-cesarean subgroups using Wilcoxon, chi-squared, and Student’s t-tests.

Results

Of 201 patients, 101 were treated with LB TAP block (LB-TAPB) and 100 without LB-TAPB. Treatment with LB-TAPB vs without LB-TAPB significantly reduced mean post-surgical opioid consumption (total, 47%; first-cesarean, 54%; repeat-cesarean, 42%; P<0.001 each) and mean AUC of pain scores (total, 46%; first-cesarean, 57%; repeat-cesarean, 40%; P<0.001 each). Patients treated with LB-TAPB had significantly shorter mean discharge-ready times (2.9 vs 3.6 days; P=0.006), PACU-ready times (138 vs 163 minutes; P=0.028), and LOS (2.9 vs 3.9 days; P<0.001). LB-TAPB significantly decreased mean times to ambulation and solid food by 39% and 31% (P<0.01 each), respectively, and numerically reduced mean time to bowel movement (26%; P=0.05). Fewer patients treated with LB-TAPB vs without LB-TAPB reported an AE (34% vs 50%; P=0.026).

Conclusion

These results suggest multimodal pain management incorporating TAP block with LB 266 mg is an effective approach to reducing opioid requirements and improving analgesia post-cesarean delivery.

Description of a regional anaesthesia technique for the dorsal cranium in the dog: a cadaveric study

OBJECTIVE

To identify landmarks and to describe a technique for nerve blockade of the dorsal cranium in dogs.

STUDY DESIGN

Anatomic cadaveric study.

ANIMALS

A total of 39 dog cadavers, weighing 18.0 ± 9.7 kg (mean ± standard deviation).

METHODS

The study was performed in three parts. In the initial part, cadavers were dissected to determine the location of the frontal, zygomaticotemporal, and major occipital nerves, and to identify prominent landmarks for their blockade. In the second part, one technique was developed to block each of the frontal and zygomaticotemporal nerves, and two techniques, rostral and caudal, were developed to block the major occipital nerve. Injection solution was 0.05% methylene blue in 0.5% bupivacaine. In the third part, cadavers were used to test the techniques developed in the second part with 0.04 mL kg^-1 of the same injectate administered at each site (maximal volume 0.5 mL per site). The length of nerve stained was measured, with a length ≥6 mm considered successful. Confidence intervals were calculated using Fisher's exact test.

RESULTS

Success rates (95% confidence interval) for the frontal, zygomaticotemporal, and rostral and caudal locations for the major occipital nerve were 94% (80-99%), 91% (76-98%), 74% (58-86%) and 77% (59-89%), respectively. With a combination of both locations, the success rate for the major occipital nerve was 100% (90-100%).

CONCLUSION AND CLINICAL RELEVANCE

This study describes a simple regional anaesthesia technique using palpable anatomical landmarks that may provide analgesia for dogs undergoing craniotomy.

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.