Local Anesthetic Systemic Toxicity in Total Joint Arthroplasty: Incidence and Risk Factors in the United States From the National Inpatient Sample 1998-2013

The Study of Ropivacaine Pharmacokinetics in a Clinical Setting: A Critical Scoping Review from the Perspective of Analytical Methodologies

Ropivacaine, a widely used regional anesthetic also used for pain management, has been increasingly used in recent years due to its increased efficacy and improved safety compared to similar anesthetics. Biomonitoring of ropivacaine and its metabolites during and after anesthesia is an essential process for ensuring therapeutic efficacy and safe usage for patients. The most useful biomonitoring tool in recent years has been liquid chromatography coupled with mass spectrometry (LC-MS/MS), which offers selectivity, sensitivity, as well as accuracy of measurements. The current manuscript summarizes and discusses the existing liquid chromatographic methods described in the literature, as well as the personal experience with developing bioanalytical and analytical methods for the quantification of ropivacaine in biological samples for clinical applications. It is focused on methodological aspects, recent advancements, challenges, and future perspectives, highlighting the importance of LC-MS/MS techniques in ropivacaine analysis.

Intravenous Lipid Emulsion Therapy in Drug Overdose and Poisoning: An Updated Review

The use of intravenous lipid emulsion (ILE) is thought to reverse the acute neurological and cardiac toxicities generated by local anesthetic and non-anesthetic drugs. The aim of this review is to provide an updated overview of ILE therapy in the management of the toxic efects of medications on humans. Indications, mechanisms of action, monitoring, dosing, lipid formulations, adverse efects, and contraindications related to ILE are highlighted. Although ILE therapy was initially utilized for local anesthetic toxicity, its use has been extended to patients with overdoses or poisoning induced by various non-local anesthetic drugs. It has been proposed that intravenous lipid droplets generate a discrete lipophilic phase in the bloodstream into which liposoluble drugs preferentially partition. This partitioning efect, known as the lipid sink phenomenon, is thought to decrease the quantity of drug content in tissues in vital organs. At the same time, other studies have also described several molecular mechanisms that may contribute to ILE efcacy. Potential adverse efects of ILE have also been identified, such as pulmonary toxicity, hypertriglyceridemia, acute pancreatitis, interference with laboratory measurements, fat overload syndrome, worsening of systemic absorption of toxin, and hepatic dysfunction. Intravenous lipid emulsion therapy is gaining wider acceptance in critical care units and emergency rooms as a possible treatment modality for liposoluble drug toxicity. Currently, recommendations on ILE administration in clinical toxicology are mainly based on published case reports and animal studies. Thus, further clinical studies are required to increase knowledge about ILE therapy.

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.

Efficacy and safety of different bupivacaine concentrations in periarticular infiltration combined with adductor canal block for bilateral total knee arthroplasty: a randomized controlled trial

BACKGROUND

Pain management for bilateral total knee arthroplasty (BTKA) often combines adductor canal block (ACB) with periarticular infiltration (PAI). However, concerns arise regarding local anesthetic toxicity. This study evaluated the efficacy and safety of different bupivacaine concentrations in simultaneous BTKA.

METHODS

Patients undergoing simultaneous BTKA under spinal anesthesia were included in the study. They received ACB with 50 mg bupivacaine for each thigh. The patients were then randomized into two groups. Group A was administered a PAI of 100 mg bupivacaine per knee (totaling 300 mg bupivacaine for ACB and PAI). Group B received a PAI with 50 mg bupivacaine per knee (totaling 200 mg bupivacaine for ACB and PAI). Postoperative pain was assessed using a visual analog scale at 4-h intervals for 48 h after surgery. Plasma bupivacaine concentrations were measured at eight specified times. Postsurgery walking ability was also evaluated.

RESULTS

Among the 57 participants analyzed, visual analog scale pain scores revealed no significant differences between the two groups. An interim analysis of plasma bupivacaine concentrations in both groups indicated no significant disparities. In group B, 93.1% managed to walk with assistance within 48 h, as opposed to group A's 71.4% (P = 0.041).

CONCLUSIONS

Combining ACB with 100 mg bupivacaine and PAI with another 100 mg bupivacaine provided effective pain relief. This combination also had a better safety profile and led to more patients walking postsurgery than when combining ACB with 100 mg bupivacaine and PAI with 200 mg bupivacaine. Thus, ACB combined with PAI with a total dose of 200 mg bupivacaine appears suitable for simultaneous BTKA.

TRIAL REGISTRATION

ClinicalTrials.gov (NCT03249662).

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.

Systemic Ropivacaine Concentrations Following Local Infiltration Analgesia and Femoral Nerve Block in Older Patients Undergoing Total Knee Arthroplasty

Purpose

The study examined the pharmacokinetic profile of fixed formulation mixtures comprising 225 mg of ropivacaine for local infiltration analgesia with or without epinephrine, and femoral nerve block in older patients presenting for orthopedic surgery and explored potential influences of block type, age, and body weight on this profile.

Patients and Methods

Twenty four patients scheduled for total knee arthroplasty were randomly assigned to three groups: femoral nerve block, local infiltration analgesia with epinephrine and local infiltration analgesia without epinephrine. Blood samples were collected at 10, 30, 60, and 120 min following the block and total plasma concentrations of ropivacaine were quantified by high performance liquid chromatography.

Results

The mean individual peak total plasma concentrations of ropivacaine in local infiltration analgesia with and without epinephrine, and femoral nerve block group were 0.334, 0.490 and 0.545 μg mL-1 (p = 0.16). Local infiltration with epinephrine group had significantly lower plasma ropivacaine concentrations at 30, 60 and 120 minutes. The plasma ropivacaine concentrations exceeded 2.2 μg mL-1 in one patient. Age, but not body weight, had a moderate correlation with peak plasma ropivacaine concentration (r = 0.37, p = 0.08).

Conclusion

Administration of a fixed 225 mg dose of ropivacaine for local infiltration analgesia with epinephrine and femoral nerve block results in plasma ropivacaine concentrations below the toxicity threshold, indicating their safety. The use of local infiltration analgesia with epinephrine provides a greater safety margin, as local infiltration analgesia without epinephrine may lead to ropivacaine concentrations associated with symptoms of local anesthetic toxicity.

Safety of Cubital Tunnel Release Under General versus Regional Anesthesia

Purpose

The aim of this study was to evaluate the occurrence of early (<6 weeks) post-operative complications following ulnar nerve decompressions at the cubital tunnel performed under regional anesthesia compared to those performed under general anesthesia.

Methods

In situ ulnar nerve decompressions at the cubital tunnel performed at a single institution from 2012 through 2019 were retrospectively reviewed. Post-operative complications were compared between subjects who underwent the procedure with regional versus general anesthesia.

Results

Ninety-one ulnar nerve in situ decompressions were included in the study, which were performed under regional anesthesia in 55 and general anesthesia in 36 cases. The occurrence of post-operative complications was not significantly different between patients who received regional (n = 7) anesthesia and general (n = 8) anesthesia. None of the complications were directly attributed to the type of anesthesia administered. The change in pre- and post-operative McGowan scores were not significantly different between anesthesia groups (p = 0.81).

Conclusion

In situ ulnar nerve decompression at the cubital tunnel under regional anesthesia does not result in increased post-operative complications compared to those surgeries performed under general anesthesia. In situ ulnar nerve decompression performed under regional anesthesia is a safe and reliable option for patients who wish to avoid general anesthesia.

Level of Evidence

III.

A Myriad of Symptoms After Spinal Anesthesia: A Case Report of Local Anesthetic Systemic Toxicity

Local anesthetics are widely used by various medical professionals. Although their usefulness is unquestionable, as with any medication, there is a possibility of iatrogenic effects. When local anesthetic systemic toxicity occurs, it might be a life-threatening condition. Knowing its existence and how to act when it arises is crucial. The clinical presentation is wide-ranging, but globally it affects the neurological and cardiovascular system, with cardiac arrest being the extreme of its presentation. The treatment is mainly supportive with an attempt to reverse the effects of the anesthetic by administering a lipid emulsion. Here, we present a clinical case of difficult management with many complications.

Comparison of in vitro and in vivo Toxicity of Bupivacaine in Musculoskeletal Applications

The recent societal debate on opioid use in treating postoperative pain has sparked the development of long-acting, opioid-free analgesic alternatives, often using the amino-amide local anesthetic bupivacaine as active pharmaceutical ingredient. A potential application is musculoskeletal surgeries, as these interventions rank amongst the most painful overall. Current literature showed that bupivacaine induced dose-dependent myo-, chondro-, and neurotoxicity, as well as delayed osteogenesis and disturbed wound healing in vitro. These observations did not translate to animal and clinical research, where toxic phenomena were seldom reported. An exception was bupivacaine-induced chondrotoxicity, which can mainly occur during continuous joint infusion. To decrease opioid consumption and provide sustained pain relief following musculoskeletal surgery, new strategies incorporating high concentrations of bupivacaine in drug delivery carriers are currently being developed. Local toxicity of these high concentrations is an area of further research. This review appraises relevant in vitro, animal and clinical studies on musculoskeletal local toxicity of bupivacaine.

Assessment of Awareness of Local Anaesthetic Systemic Toxicity (LAST) among Postgraduate Trainees

INTRODUCTION

Although uncommon, local anaesthetic systemic toxicity (LAST) may impose fatal risk to the patients. We investigated the awareness of LAST and knowledge on local anaesthetics among our postgraduate trainees.

MATERIALS AND METHODS

A total of 134 postgraduate trainees from the departments of general surgery (Surgical), orthopaedic surgery (Ortho), otorhinolaryngology (ENT), obstetrics and gynaecology (OBGYN), as well as anaesthesiology and intensive care (Anaesth) were recruited. A validated questionnaire was used to assess awareness and knowledge. All participants attended a medical-education session and completed the questionnaire as preassessment and postassessment. Data were analysed, and comparisons between disciplines were conducted.

RESULTS

The trainees' awareness of LAST was overall poor at preassessment which improved almost 6-folds at postassessment. Surprisingly, only 20 (45.5%) participants from the anaesthesiology group had awareness of LAST at preassessment, and none of the participants were from surgical, orthopaedic, and obstetrics and gynaecology departments. Preassessment scores were significantly higher in the anaesth group as compared to all other groups; with a difference in the average score for Anaesth vs Surgical of 3.46 (95%, CI:2.17, 4.74), Anaesth vs Ortho of 3.64 (95%, CI:2.64, 4.64), Anaesth vs ENT of 3.43 (95%, CI:2.20, 4.67), and Anaesth vs OBGYN of 6.93 (95%, CI:5.64, 8.21). However, there was no significant difference of awareness scores between all participants at postassessment scores.

CONCLUSION

The overall level of awareness was poor. However, the implementation of an education session significantly improved the knowledge and awareness across all disciplines.

Safety of treatment options available for postoperative pain

IntroductionPostoperative pain is one of the most common adverse events after surgery and has been shown to increase the risk of other complications. On the other hand, liberal opioid use in the perioperative period is also associated with risk of adverse events. The current consensus is therefore to provide multimodal, opioid minimizing analgesia after surgery.Areas CoveredIn this review, we will discuss the benefits and risks associated with non-opioid analgesics, including non-steroidal anti-inflammatory drugs, gabapentinoids, ketamine, α-2 agonists, and corticosteroids. In addition, we will discuss the general and block-specific risks associated with regional anesthestic techniques.Expert OpinionAdverse events associated with non-opioid analgesics are rare outside their specific contraindicated patient groups, especially when dosed appropriately. α-2 agonists can cause transient hypotension and bradycardia, and gabapentinoids may cause sedation in higher risk patient populations. Regional anesthesia techniques are generally safe when done by an experienced practitioner. We therefore encourage the development of standardized multimodal analgesic protocols, which may facilitate opioid minimization and lead to better patient outcomes.

Patients Undergoing Primary Total Joint Arthroplasty with Primary Hypercoagulable States

Objective

To analyze perioperative complications, resource consumption, and inpatient mortality of patients who receive total joint arthroplasty (TJA) with a concomitant diagnosis of a primary hypercoagulable state (PHS). The following questions were posed in the present paper. First, do patients undergoing TJA with PHS have increased risk of deep venous thrombosis (DVT), pulmonary embolism (PE), and periprosthetic joint infection (PJI)? Second, what other in‐hospital complications are more likely among PHS patients undergoing TJA? Third, do TJA patients with PHS usually consume greater in‐hospital resources? Fourth, do PHS patients suffer higher mortality rates compared to non‐PHS patients? Finally, have PHS patients received proper anticoagulant management in past arthroplasties?

Methods

The National Inpatient Sample (NIS) database for the years between 2003 and 2014 was searched to identify patients undergoing primary TJA. Patients with PHS were identified with the ICD‐9‐CM code 289.81. The χ²‐test, the Pearson test, and adjusted multivariate regression analysis were performed to evaluate the difference and odds ratios between the positive and negative diagnosis groups.

Results

From 2003 to 2014, a total of 2,044,356 patients were identified in the NIS as undergoing primary total hip arthroplasty (THA) or total knee arthroplasty (TKA) in the United States. A total of 4664 patients (0.2%) were identified as having PHS. Compared with the non‐PHS group, TJA patients with PHS had a higher risk of DVT (THA: odds ratio [OR] = 8.343, 95% CI: 5.362–12.982, P < 0.001; TKA: OR = 4.712, 95% CI: 3.560–6.238, P < 0.001) but did not have increased risk of PE (THA: OR = 1.306, 95% CI: 0.48–3.555, P = 0.602; TKA: OR = 1.143, 95% CI: 0.687–1.903), and only PHS patients in the THA group had higher risks of inpatient mortality (OR = 3.184, 95% CI: 1.348–7.522, P = 0.008) and periprosthetic joint infection (OR = 3.343, 95% CI: 1.084–10.879, P = 0.036). In addition, PHS patients had extended length of stay, higher total costs, and increased risks of certain other complications, such as peripheral vascular disease, hemorrhage, and thrombophlebitis.

Conclusion

In the present study, PHS patients had higher risks of DVT, greater in‐hospital resource consumption, and certain other perioperative complications. However, PHS was not associated with increased risk of PE in TJA patients in the United States between 2003 and 2014. While potential hazards of PHS have already been recognized, the present study revealed additional concerns and demonstrated that further improvements in the perioperative management of patients with hereditary hypercoagulable disorders are essential.

Superior hypogastric nerve block (SHNB) for pain control after uterine fibroid embolization (UFE): technique and troubleshooting

Background

Superior Hypogastric nerve Block (SHNB) has been shown to be an effective pain management technique after Uterine Fibroid Embolization (UFE), reducing the need for opiates and allowing same-day discharge after UFE. In this technical note we discuss relevant anatomy and technical details in performing SHNB.

Main body

The Superior hypogastric plexus (SHP) is the part of the abdominopelvic sympathetic nervous system that provides a targeted intervention to sympathetic-mediated pain pathways of pelvic organs and a target for an anterior approach Superior Hypogastric nerve Block after embolization. Vascular structures are in close relation to the intended site of target of the SHP at the L5 vertebral body include aortic bifurcation and IVC confluence, hence a detailed knowledge of this is essential. A step by step technical approach to SHNB includes patient positioning for the block, image guidance and needle positioning, choice and technique of anesthetic injection. Traversing a large fibroid uterus, inadvertent vascular opacification and Local anesthetic systemic toxicity present challenges to performing the block and are addressed.

Conclusion

Superior Hypogastric nerve Block (SHNB) can be a useful tool in the Interventional armamentarium to make UFE a better experience for patients with fibroids, allowing for better pain control as well as facilitating same day discharge. Performing SHNB appear to be can be performed with technical ease for an interventional radiologist.

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.

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.

Regional Nerve Blocks-Best Practice Strategies for Reduction in Complications and Comprehensive Review

PURPOSE OF REVIEW

Understanding the etiologies of the complications associated with regional anesthesia and implementing methods to reduce their occurrence provides an opportunity to foster safer practices in the delivery of regional anesthesia.

RECENT FINDINGS

Neurologic injuries following peripheral nerve block (PNB) and neuraxial blocks are rare, with most being transient. However, long-lasting and devastating sequelae can occur with regional anesthesia. Risk factors for neurologic injury following PNB include type of block, injection in the presence of deep sedation or general anesthesia, presence of existing neuropathy, mechanical trauma from the needle, pressure injury, intraneural injection, neuronal ischemia, iatrogenic injury related to surgery, and local anesthetic neurotoxicity. The present investigation discusses regional blocks, complications of regional blocks, risk factors, site-specific limitations, specific complications and how to prevent them from happening, avoiding complications in regional anesthesia, and the future of regional anesthesia.

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.