Pharmacological and clinical implications of local anaesthetic mixtures: a narrative review.

Various techniques have been explored to prolong the duration and improve the efficacy of local anaesthetic nerve blocks. Some of these involve mixing local anaesthetics or adding adjuncts. We did a literature review of studies published between 01 May 2011 and 01 May 2021 that studied specific combinations of local anaesthetics and adjuncts. The rationale behind mixing long- and short-acting local anaesthetics to hasten onset and extend duration is flawed on pharmacokinetic principles. Most local anaesthetic adjuncts are not licensed for use in this manner and the consequences of untested admixtures and adjuncts range from making the solution ineffective to potential harm. Pharmaceutical compatibility needs to be established before administration. The compatibility of drugs from the same class cannot be inferred and each admixture requires individual review. Precipitation on mixing (steroids, non-steroidal anti-inflammatory drugs) and subsequent embolisation can lead to serious adverse events, although these are rare. The additive itself or its preservative can have neurotoxic (adrenaline, midazolam) and/or chondrotoxic properties (non-steroidal anti-inflammatory drugs). The prolongation of block may occur at the expense of motor block quality (ketamine) or block onset (magnesium). Adverse effects for some adjuncts appear to be dose-dependent and recommendations concerning optimal dosing are lacking. An important confounding factor is whether studies used systemic administration of the adjunct as a control to accurately identify an additional benefit of perineural administration. The challenge of how best to prolong block duration while minimising adverse events remains a topic of interest with further research required.

The Role of Dexmedetomidine as an Additive to Intravenous Regional Anesthesia: A Systematic Review and Meta-analysis.

BACKGROUND: Intravenous Regional Anesthesia (IVRA) is a reliable and cost-effective anesthetic method for minor surgical procedures to the extremities. Limitations of this block include tourniquet discomfort, short duration of anesthesia, and absence of postoperative analgesia. Dexmedetomidine has been used as an adjuvant to minimize these negative characteristics with inconclusive results. AIM: To perform a systematic review of the existing evidence on the role of dexmedetomidine as an additive to intravenous regional anesthesia in upper limb surgery. STUDY DESIGN: Systematic Review and Meta-analysis. METHODS: The databases searched were MEDLINE, Embase, PubMed, CINAHL, Cochrane Database of Systematic Reviews, Cochrane Central Register of Controlled Trials databases, and clinicaltrials. gov (1990-2019). Seven randomized controlled trials (RCTs) were included. We analyzed the duration of analgesia, onset time of sensory and motor block, intraoperative tourniquet pain scores, the incidence of tourniquet pain, need for rescue analgesia, intraoperative rescue analgesia consumption, sedation scores, postoperative pain scores, and anesthesia quality. RESULTS: Intraoperative analgesia duration (MD 11.08 min; 95% CI 5.42, 16.75; P < .0001) was longer and sensory block onset time (MD -2.10 min; 95% CI -3.345, -0.86; P = .00009) was shorter in the dexmedetomidine group. Anesthesia quality scores (MD 0.58; 95% CI 0.47, 0.70; P < .00001) and postoperative sedation scores (MD 1.03; 95% CI 0.88, 1.24; P < .00001) were significantly higher. There was a significant reduction in intraoperative rescue analgesia consumption (MD -19.70 mg; 95% CI -24.15, -15.26; P < .00001) in the dexmedetomidine group. The risk of tourniquet pain as well as postoperative pain scores were lower in favor of dexmedetomidine. The addition of dexmedetomidine to IVRA slightly increased the risk of sedation. A limitation of our study is that some of the interesting outcomes derive from a small number of RCTs. CONCLUSION: The addition of dexmedetomidine to IVRA ameliorates the block's characteristics and carries a low risk of potential side effects.

Defining success in regional anaesthesia.

Utilisation of regional anaesthesia is increasing globally; however, it remains challenging to determine the overall benefit of individual regional anaesthesia procedures. Like any peri-operative intervention, the benefit to the patient and healthcare system must outweigh any patient risk or resource implications. This review aims to identify markers of success in regional anaesthesia, categorise these into an objective framework and rationalise suggestions on how measuring outcomes in regional anaesthesia can be used to develop the widespread performance of this evolving subspecialty. This framework of measuring success of regional anaesthesia contains four pillars: patient-centred, population-centred, healthcare-centred and training-centred outcomes. Each pillar of success contains several outcomes which provide a structure for the measurement and development of regional anaesthesia success on a global scale.

Regional anaesthesia quality indicators for adult patients undergoing non-cardiac surgery: a systematic review.

Improvement in healthcare delivery depends on the ability to measure outcomes that can direct changes in the system. An overview of quality indicators within the field of regional anaesthesia is lacking. This systematic review aims to synthesise available quality indicators, as per the Donabedian framework, and provide a concise overview of evidence-based quality indicators within regional anaesthesia. A systematic literature search was conducted using the databases MEDLINE, Embase, CINAHL and Cochrane from 2003 to present, and a prespecified search of regional anaesthesia society websites and healthcare quality agencies. The quality indicators relevant to regional anaesthesia were subdivided into peri-operative structure, process and outcome indicators as per the Donabedian framework. The methodological quality of the indicators was determined as per the Oxford Centre for Evidence-Based Medicine's framework. Twenty manuscripts met our inclusion criteria and, in total, 68 unique quality indicators were identified. There were 4 (6%) structure, 12 (18%) process and 52 (76%) outcome indicators. Most of the indicators were related to the safety (57%) and effectiveness (19%) of regional anaesthesia and were general in nature (60%). In addition, most indicators (84%) were based on low levels of evidence. Our study is an important first step towards describing quality indicators for the provision of regional anaesthesia. Future research should focus on the development of structure and process quality indicators and improving the methodological quality and usability of these indicators.

Peripheral Nerve Blockade with Combined Standard and Liposomal Bupivacaine in Major Lower-Extremity Amputation.

BACKGROUND AND OBJECTIVES: Optimizing perioperative analgesia for patients undergoing major lower-extremity amputation remains a considerable challenge. The utility of liposomal bupivacaine as a component of peripheral nerve blockade for lower-extremity amputation is unknown. METHODS: We conducted an observational study comparing three different perioperative analgesic techniques for adults undergoing major lower-extremity amputation under general anesthesia between 2012 and 2017 at an academic medical center: (1) no regional anesthesia, (2) peripheral nerve blockade with standard bupivacaine, and (3) peripheral nerve blockade with a mixture of standard and liposomal bupivacaine. The primary outcome of cumulative opioid oral morphine milligram equivalent utilization in the first 72 hours postoperatively was compared across groups utilizing multivariable linear regression. RESULTS: A total of 631 unique anesthetics were included for 578 unique patients, including 416 (66%) without regional anesthesia, 131 (21%) with peripheral nerve blockade with a mixture of standard and liposomal bupivacaine, and 84 (13%) with peripheral nerve blockade with standard bupivacaine alone. Cumulative morphine equivalents were lower in those receiving peripheral nerve blockade with combined standard and liposomal bupivacaine compared with those not receiving regional anesthesia (multiplicative increase 0.67; 95% CI 0.50 to 0.90; P = 0.007). There were no significant differences in opioid utilization between peripheral nerve blockade groups (P = 0.59). CONCLUSIONS: Peripheral nerve blockade is associated with reduced opioid requirements after lower-extremity amputation compared with general anesthesia alone. However, the incorporation of liposomal bupivacaine is not significantly different to blockade employing only standard bupivacaine.

Education and training in ultrasound-guided regional anaesthesia and pain medicine.

PURPOSE OF REVIEW: Effective and safe regional anaesthesia and pain medicine procedures require clinicians to learn and master complex theoretical knowledge and motor skills. This review aims to summarize articles relevant to education and training in these skill sets in the previous 2 years. RECENT FINDINGS: Twenty-two articles were identified, investigating nine out of the 13 top-ranked research topics in education and training in regional anaesthesia. Research topics addressed by these articles included prerotation simulation, deliberate practice combined with formative assessment tools, validation of assessment tools, three-dimensional-printed models, and knowledge translation from simulation to clinical practice. Emerging concepts investigated for their applications in regional anaesthesia included eye-tracking as a surrogate metric when evaluating proficiency, and elastography aiding visual salience to distinguish appropriate perineural and inappropriate intraneural injections. SUMMARY: Research into education and training in regional anaesthesia covered multiple and diverse topics. Methodological limitations were noted in several articles, reflecting the difficulties in designing and conducting medical education studies. Nonetheless, the evidence-base continues to mature and innovations provide exciting future possibilities.

Management of Cardiac Implantable Electrical Devices in Patients Undergoing Radiofrequency Ablation for Spine Pain: Physician Survey and Review of Guidelines.

BACKGROUND: More patients with cardiac implantable electrical devices (CIEDs) are presenting to spine and pain practices for radiofrequency ablation (RFA) procedures for chronic pain. Although the potential for electromagnetic interference (EMI) affecting CIED function is known with RFA procedures, available guidelines do not specifically address CIED management for percutaneous RFA for zygapophyseal (z-joint) joint pain, and thus physician practice may vary. OBJECTIVES: To better understand current practices of physicians who perform RFA for chronic z-joint pain with respect to management of CIEDs. Perioperative CIED management guidelines are also reviewed to specifically address risk mitigation strategies for potential EMI created by ambulatory percutaneous spine RFA procedures. STUDY DESIGN: Web-based provider survey and narrative review. SETTING: Multispecialty pain clinic, academic medical center. METHODS: A web-based survey was created using Research Electronic Data Capture (REDCap). A survey link was provided via e-mail to active members of the Spine Intervention Society (SIS), American Society of Regional Anesthesia and Pain Medicine, as well as distributed freely to community Pain Physicians and any receptive academic departments of PM&R or Anesthesiology. The narrative review summarizes pertinent case series, review articles, a SIS recommendation statement, and multi-specialty peri-operative guidelines as they relate specifically to spine RFA procedures. RESULTS: A total of 197 clinicians participated in the survey from diverse clinical backgrounds, including anesthesiology, physical medicine and rehabilitation, radiology, neurosurgery, and neurology, with 81% reporting fellowship training. Survey responses indicate wide variability in provider management of CIEDs before, during, and after RFA for z-joint pain. Respondents indicated they would like more specific guidelines to aid in management and decision-making around CIEDs and spine RFA procedures. Literature review yielded several practice guidelines related to perioperative management of CIEDs, but no specific guideline for percutaneous spine RFA procedures. However, combining the risk mitigation strategies provided in these guidelines, with interventional pain physician clinical experience allows for reasonable management recommendations to aid in decision-making. LIMITATIONS: Although this manuscript can serve as a review of CIEDs and aid in management decisions in patients with CIEDs, it is not a clinical practice guideline. CONCLUSIONS: Practice patterns vary regarding CIED management in ambulatory spine RFA procedures. CIED presence is not a contraindication for spine RFA but does increase the complexity of a spine RFA procedure and necessitates some added precautions. KEY WORDS: Radiofrequency ablation, neurotomy, cardiac implantable electrical device, zygapophyseal joint, spondylosis, neck pain, low back pain, chronic pain.

Reconfiguring the scope and practice of regional anesthesia in a pandemic: the COVID-19 perspective.

The COVID-19 outbreak is on the world. While many countries have imposed general lockdown, emergency services are continuing. Healthcare professionals have been infected with the virulent severe acute respiratory syndrome coronavirus-2 (SARS), which spreads by close contact and aerosols. The anesthesiologist is particularly vulnerable to aerosols while performing intubation and other airway related procedures. Regional anesthesia (RA) minimizes the need for airway manipulation and the risks of cross infection to other patients, and the healthcare personnel. In this context, for prioritizing RA over general anesthesia, wherever possible, a structured algorithmic approach is outlined. The role of percentage saturation of hemoglobin with oxygen (oxygen saturation), blood pressure and early use of point-of-care ultrasound in differential diagnosis and specific management is detailed. The perioperative anesthetic implications of multisystem manifestations of COVID-19, anesthetic management options, the scope of RA and considerations for its safe conduct in operating rooms is described. An outline for safe and rapid training of healthcare personnel, with an Entrustable Professional Activity framework for ascertaining the practice readiness among trained residents for RA in COVID-19, is suggested. These are the authors' experiences gained from the current pandemic and similar SARS, Middle East Respiratory Syndrome and influenza outbreaks in recent past faced by our authors in Singapore, India, Hong Kong and Canada.

Safety guideline: neurological monitoring associated with obstetric neuraxial block 2020: A joint guideline by the Association of Anaesthetists and the Obstetric Anaesthetists' Association.

Serious neurological lesions such as vertebral canal haematoma are rare after obstetric regional analgesia/anaesthesia, but early detection may be crucial to avoid permanent damage. This may be hampered by the variable and sometimes prolonged recovery following 'normal' neuraxial block, such that an underlying lesion may easily be missed. These guidelines make recommendations for the monitoring of recovery from obstetric neuraxial block, and escalation should recovery be delayed or new symptoms develop, with the aim of preventing serious neurological morbidity.

Variation Between and Within Hospitals in Single Injection Caudal Local Anesthetic Dose: A Report From the Pediatric Regional Anesthesia Network.

BACKGROUND: Given that variation exists in health care utilization, expenditure, and medical practice, there is a paucity of data on variation within the practice of anesthesia. The Pediatric Regional Anesthesia Network (PRAN) data lend itself to explore whether different medical practice patterns exist and if there are nerve blocks with more local anesthetic dosing variation than others. The primary aim of this study was to quantify variation in single injection caudal block dosing, and the secondary aim was to explore possible causes for variation (eg, number of blocks performed versus geographic location). METHODS: We queried the PRAN database for single injection caudal blocks in children <1 year of age. Data were analyzed for local anesthetic dose, variation within and across institutions, and possible causes. RESULTS: Mean dose of bupivacaine equivalents per kilogram (BE·kg) among sites ranged from 1.39 to 2.22 with an interdecile range (IDR) containing the mid 80% of all doses ranging from 0.21 to 1.48. Mean dose (BE·kg) was associated with site, age, weight, and local anesthetic used (all P < .0001). Cohen's F effect size estimate was 10 times higher for site (0.65) than for age (0.05) or weight (0.02). Variation (IDR) was not related to number of blocks done at each site (P = .23). Mean volume per kilogram was 0.9± ± 0.2 (mean ± ±standard deviation) and was more strongly associated with site (Cohen's F 0.3) than age (0.04) or weight (0.07). CONCLUSIONS: Wide variation in caudal local anesthetic dosing and administered volume exists. This variation is independent of the number of cases performed at each center but rather is determined by study site (ie, variation between centers) with considerable additional variation within study centers, suggesting additional variability dependent on individual practitioners. While there are legitimate reasons to vary dosing, the current approach is inconsistent and not supported by strong evidence over giving a standardized dose.

Regional anesthesia and pain management in patients with sleep apnea: can they improve outcomes?

PURPOSE OF REVIEW: In several guidelines, regional anesthesia and analgesia have been suggested as safer alternatives for general anesthesia and systemic analgesia for their safety profile in patients suffering from obstructive sleep apnea (OSA). However, the underlying scientific basis is still evolving. The present review is intended to provide an up-to-date account on the question whether the use of regional anesthesia improves outcomes in patients with OSA. RECENT FINDINGS: A number of studies found favorable effects of regional anesthesia used in patients with OSA, including reduced incidence of major perioperative complications such as the need for mechanical ventilation, reintubation and pulmonary/cardiac complications. No negative effects of regional anesthesia specific to patients with OSA were found. Regional anesthesia was most effective when used as a sole technique, but also carried benefits when added to general anesthesia. The majority of available literature focuses on orthopedic surgery and neuraxial anesthesia. SUMMARY: Regional anesthesia can be recommended as a good strategy to treat patients with OSA whenever feasible, as it reduces the incidence of potentially catastrophic perioperative complications. However, the breadth of both surgical and regional anesthetic techniques analyzed is limited; further research should focus on extending the knowledge base beyond neuraxial anesthesia and orthopedics.

Updates on pediatric regional anesthesia safety data.

PURPOSE OF REVIEW: The clinical practice of anesthesia continues to evolve and grow toward increasing quality and safety while improving the patient and family perioperative experience. Within the realm of pediatric anesthesia, advances in regional anesthesia techniques are important part in this aim. RECENT FINDINGS: The aim of this review is to provide an update on recent advances in pediatric regional anesthesia. This includes an emphasis on safety data from large datasets that previously were not available. In addition, novel blocks within pediatric regional anesthesia will be described. SUMMARY: Large data sets have given clinical providers information into the practice of regional anesthesia. It has confirmed the safety of common regional anesthetic techniques in addition to providing guidance to improving outcomes for children.

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.

Focused assessment with sonography in trauma (FAST) for the regional anesthesiologist and pain specialist.

This article in our point-of-care ultrasound (PoCUS) series is dedicated to the role the focused assessment with sonography in trauma (FAST) exam plays for the regional anesthesiologist and pain specialists in the perioperative setting. The FAST exam is a well-established and extensively studied PoCUS exam in both surgical and emergency medicine literature with over 20 years demonstrating its benefit in identifying the presence of free fluid in the abdomen following trauma. However, only recently has the FAST exam been shown to be beneficial to the anesthesiologist in the perioperative setting as a means to identify the extravasation of free fluid into the abdomen from the hip joint following hip arthroscopy. In this article, we will describe how to obtain the basic FAST views (subcostal four-chamber view, perihepatic right upper quadrant view, perisplenic left upper quadrant view, and pelvic view in the longitudinal and short axis) as well as cover the relevant sonoanatomy. We will describe pathological findings seen with the FAST exam, primarily free fluid in the peritoneal space as well as in the pericardial sac. As is the case with any PoCUS skill, the application evolves with understanding and utilization by new clinical specialties. Although this article will provide clinical examples of where the FAST exam is beneficial to the regional anesthesiologist and pain specialist, it also serves as an introduction to this powerful PoCUS skill in order to encourage clinical practitioners to expand the application of the FAST exam within the scope of regional anesthesia and pain management practice.

Thoracic trauma in military settings: a review of current practices and recommendations.

PURPOSE OF REVIEW: To examine current literature on thoracic trauma related to military combat and to explore its relevance to the civilian population. RECENT FINDINGS: Damage control resuscitation (DCR) has improved the management of hemorrhaging trauma patients. Permissive hypotension below 110 mmHg and antifibrinolytic use during DCR is widely accepted, whereas the use of freeze-dried plasma and whole blood is gaining popularity. The Modified Physiologic Triaging Tool can be used for primary triage and it may have applications in civilian trauma systems. Although Tactical Combat Casualty Care protocol recommends the Cric-Key device for surgical cricothyroidotomies, other devices may offer comparable performance. Recommendations for regional anesthesia after blunt trauma are not well defined. Increasing amounts of evidence favor the use of extracorporeal membrane oxygenation for refractory hypoxemia and resuscitative endovascular balloon occlusion of the aorta (REBOA) for severe hemorrhage. REBOA outcomes are potentially improved by partial occlusion and small 7 Fr catheters. SUMMARY: The Global War on Terror has provided opportunities to better understand and treat thoracic trauma in military settings. Trauma registries and other data sources have contributed to significant advancements in the management of thoracic trauma in military and civilian populations.

Practical Regional Anesthesia Guide for Elderly Patients.

Ultrasound-guided regional anesthesia is an important part of the practice of anesthesia for the elderly population, the growth of which will continue to outpace that of the younger population due to improvements in lifespan worldwide. The elderly patient is uniquely vulnerable to the effects of systemic anesthetic drugs, and our understanding of the potential toxicities that general anesthetics can have on the elderly brain and body continues to evolve. Aging impacts both the pharmacokinetics and pharmacodynamics of sedative medications and local anesthetics. Alongside the physiologic aging process often comes a myriad of pathologic co-morbidities that can accumulate with age, and result in a great variability of physiologic reserve. This variability in overall functional status is described by a newer concept termed 'frailty,' which is used to evaluate and risk-stratify elderly patients perioperatively. The choice for regional anesthesia is based on a combination of factors such as duration of surgery, pre-existing patient risk factors, and the skill and technique of the anesthesiologist. The utilization of preoperative and intraoperative sedation is now recognized as a key component in maximizing the safety and success rate of regional anesthesia. Excellent pain management with minimal to no sedation during the operation may have benefits that extend far beyond the immediate perioperative setting. Regional anesthesia is increasingly integrated as an important part of multimodal enhanced recovery after surgery (ERAS) protocols, which aim to decrease the cost, enhance safety, and improve the patient's subjective experience during and after hospitalization. Ultrasound-guided techniques, recently developed regional blocks, medications for sedation, and local anesthetics are reviewed in this article.

Evaluation of the B-Smart manometer and the CompuFlo computerized injection pump technology for accurate needle-tip injection pressure measurement during peripheral nerve blockade.

BACKGROUND AND OBJECTIVES: The exact mechanism of peripheral nerve blocks causing/leading to nerve injury remains controversial. Evidence from animal experiments suggests that intrafascicular injection resulting in high injection pressure has the potential to rupture nerve fascicles and may consequently cause permanent nerve injury and neurological deficits. The B-Smart (BS) in-line manometer and the CompuFlo (CF) computerized injection pump technology are two modalities used for monitoring pressure during regional anesthesia. This study sought to explore the accuracy of these two technologies in measuring needle-tip pressures in a simulated environment. METHODS: In seven simulated needle-syringe combinations, the BS and the CF devices were connected in series through a closed system and attached to a digital manometer at the tip of various needles. The pressures were evaluated in three trials per needle-syringe combination. Sensitivity, specificity, positive predictive value, negative predictive value, and accuracy (F1 Score) were determined for each needle type and overall. RESULTS: For pressures ≥15 psi and ≥20 psi, respectively, the CF device demonstrated a sensitivity of 100%, 100%; specificity of 96%, 98%; positive predictive value 93%, 93%; and negative predictive value of 100%, 100%. The BS device demonstrated a sensitivity of 60%, 100%; specificity of 99%, 95%; positive predictive value of 96%, 85%; and negative predictive value of 85%, 100%. Accuracy, as measured by the F1 Score, for detecting a pressure of ≥15 psi was 0.96 for the CF and 0.74 for the BS. CONCLUSIONS: Future research is needed to explore in-vivo performance and evaluate whether either of these devices can impact on clinical outcomes.

Anesthesia in Patients With Multiple-System Atrophy: A Narrative Review and Practice Guidance.

Multiple-system atrophy, a rare adult-onset neurodegenerative disease, is associated with autonomic dysfunction, features of parkinsonism, and cerebellar ataxia. This article discusses multiple-system atrophy pathophysiology, clinical presentation, and perioperative issues pertinent to anesthesia.