Celebrating the state of the art and innovations in regional anaesthesia in the British Journal of Anaesthesia.

To coincide with the annual scientific meeting of Regional Anaesthesia UK in London 2024, where there is a joint scientific session with the British Journal of Anaesthesia, a special regional anaesthesia edition of the journal has been produced. This editorial offers some highlights from the manuscripts contained within the special edition.

The educational impact of technology-enhanced learning in regional anaesthesia: a scoping review.

BACKGROUND: Effective training in regional anaesthesia (RA) is paramount to ensuring widespread competence. Technology-based learning has assisted other specialties in achieving more rapid procedural skill acquisition. If applicable to RA, technology-enhanced training has the potential to provide an effective learning experience and to overcome barriers to RA training. We review the current evidence base for use of innovative technologies in assisting learning of RA. METHODS: Using scoping review methodology, three databases (MEDLINE, Embase, and Web of Science) were searched, identifying 158 relevant citations. Citations were screened against defined eligibility criteria with 27 studies selected for inclusion. Data relating to study details, technological learning interventions, and impact on learner experience were extracted and analysed. RESULTS: Seven different technologies were used to train learners in RA: artificial intelligence, immersive virtual reality, desktop virtual reality, needle guidance technology, robotics, augmented reality, and haptic feedback devices. Of 27 studies, 26 reported a positive impact of technology-enhanced RA training, with different technologies offering benefits for differing components of RA training. Artificial intelligence improved sonoanatomical knowledge and ultrasound skills for RA, whereas needle guidance technologies enhanced confidence and improved needling performance, particularly in novices. Immersive virtual reality allowed more rapid acquisition of needling skills, but its functionality was limited when combined with haptic feedback technology. User friendly technologies enhanced participant experience and improved confidence in RA; however, limitations in technology-assisted RA training restrict its widespread use. CONCLUSIONS: Technology-enhanced RA training can provide a positive and effective learning experience, with potential to reduce the steep learning curve associated with gaining RA proficiency. A combined approach to RA education, using both technological and traditional approaches, should be maintained as no single method has been shown to provide comprehensive RA training.

Educational outcomes of simulation-based training in regional anaesthesia: a scoping review.

BACKGROUND: Structured training in regional anaesthesia includes pretraining on simulation-based educational platforms to establish a safe and controlled learning environment before learners are provided clinical exposure in an apprenticeship model. This scoping review was designed to appraise the educational outcomes of current simulation-based educational modalities in regional anaesthesia. METHODS: This review conformed to PRISMA-ScR guidelines. Relevant articles were searched in PubMed, Scopus, Google Scholar, Web of Science, and EMBASE with no date restrictions, until November 2023. Studies included randomised controlled trials, pre-post intervention, time series, case control, case series, and longitudinal studies, with no restrictions to settings, language or ethnic groups. The Kirkpatrick framework was applied for extraction of educational outcomes. RESULTS: We included 28 studies, ranging from 2009 to 2023, of which 46.4% were randomised controlled trials. The majority of the target population was identified as trainees or residents (46.4%). Higher order educational outcomes that appraised translation to real clinical contexts (Kirkpatrick 3 and above) were reported in 12 studies (42.9%). Two studies demonstrated translational patient outcomes (Level 4) with reduced incidence of paraesthesia and clinical complications. The majority of studies appraised Level 3 outcomes of performance improvements in either laboratory simulation contexts (42.9%) or demonstration of clinical performance improvements in regional anaesthesia (39.3%). CONCLUSIONS: There was significant heterogeneity in the types of simulation modalities used, teaching interventions applied, study methodologies, assessment tools, and outcome measures studied. When improvisations were made to regional anaesthesia simulation platforms (hybrid simulation), there were sustained educational improvements beyond 6 months. Newer technology-enhanced innovations such as virtual, augmented, and mixed reality simulations are evolving, with early reports of educational effectiveness.

Feasibility of ultrasound-guided nerve blocks in simulated microgravity: a proof-of-concept study for regional anaesthesia during deep space missions.

BACKGROUND: With crewed deep space exploration on the horizon, preparation for potential astronaut health crises in space missions has become vital. Administration of anaesthesia and analgesia presents many challenges owing to constraints specific to space (physiologic and ergonomic challenges associated with microgravity) and nonspecific factors (isolation and lack of supplies). Regional anaesthesia can be the safest option; however, we hypothesised that the ergonomics of microgravity would compromise ease and accuracy of nerve blocks. METHODS: We evaluated the feasibility of regional anaesthesia in a simulated microgravity environment (free-floating underwater conditions) using a meat (bovine muscle) model. Forty meat models were randomised for injection under simulated microgravity or normal gravity conditions. Success rates were determined by blinded assessors after injection. Parameters assessed included time to block, ease of image acquisition, and ease of needle placement. RESULTS: The median time to block in normal gravity was 27 (interquartile range 21-69) s vs 35 (interquartile range 22-48) s in simulated microgravity (P=0.751). Ease of image acquisition was similar in both conditions, as was ease of needle placement. There was no significant difference in the rate of accidental intraneural injections (5% vs 5%), with block success rates comparable in both scenarios (80% normal gravity vs 85% microgravity, P>0.999). CONCLUSIONS: Regional anaesthesia appears feasible for experts in simulated microgravity despite the ergonomic challenges. Although our model has limitations and might not fully capture the complexities of actual space conditions, it provides a foundation for future research into anaesthesia and analgesia during deep space missions.

Peripheral regional anaesthesia and outcomes: a narrative review of the literature from 2013 to 2023.

The use of peripheral regional anaesthesia continues to increase, yet the evidence supporting its use and impact on relevant outcomes often lacks scientific rigour, especially when considering the use of specific blocks for a particular surgical indication. In this narrative review, we consider the relevant literature in a 10-yr period from 2013. We performed a literature search (MEDLINE and EMBASE) for articles reporting randomised controlled trials and other comparative trials of peripheral regional anaesthetic blocks vs systemic analgesia in adult patients undergoing surgery. We evaluated measures of effective treatment and complications. A total of 128 studies met our inclusion criteria. There remains variability in the technical conduct of blocks and the outcomes used to evaluate them. There is a considerable body of evidence to support the use of interscalene blocks for shoulder surgery. Saphenous nerve (motor-sparing) blocks provide satisfactory analgesia after knee surgery and are preferred to femoral nerve blocks which are associated with falls when patients are mobilised early as part of enhanced recovery programmes. There are additional surgical indications where the efficacy of cervical plexus, intercostal nerve, and ilioinguinal/iliohypogastric nerve blocks have been demonstrated. In the past 10 yr, there has been a consolidation of the evidence indicating benefit of peripheral nerve blocks for specific indications. There remains great scope for rigorous, multicentre, randomised controlled trials of many peripheral nerve blocks. These would benefit from an agreed set of patient-centred outcomes.

Examining disparities in regional anaesthesia and pain medicine.

In high-resource countries, health disparities exist in both treatment approaches and health outcomes. Race and ethnicity can serve as proxies for other socioeconomic factors and social determinants of health such as income, education, social support, and residential neighbourhood, which strongly influence health outcomes and disparities. In regional anaesthesia and pain medicine, disparities exist across several surgical specialties including obstetrics, paediatrics, and orthopaedic surgery. Understanding these disparities will facilitate development of solutions aimed at eliminating disparities at the patient, physician/provider, and healthcare system levels.

Research priorities in regional anaesthesia: an international Delphi study.

BACKGROUND: Regional anaesthesia use is growing worldwide, and there is an increasing emphasis on research in regional anaesthesia to improve patient outcomes. However, priorities for future study remain unclear. We therefore conducted an international research prioritisation exercise, setting the agenda for future investigators and funding bodies. METHODS: We invited members of specialist regional anaesthesia societies from six continents to propose research questions that they felt were unanswered. These were consolidated into representative indicative questions, and a literature review was undertaken to determine if any indicative questions were already answered by published work. Unanswered indicative questions entered a three-round modified Delphi process, whereby 29 experts in regional anaesthesia (representing all participating specialist societies) rated each indicative question for inclusion on a final high priority shortlist. If ≥75% of participants rated an indicative question as 'definitely' include in any round, it was accepted. Indicative questions rated as 'definitely' or 'probably' by <50% of participants in any round were excluded. Retained indicative questions were further ranked based on the rating score in the final Delphi round. The final research priorities were ratified by the Delphi expert group. RESULTS: There were 1318 responses from 516 people in the initial survey, from which 71 indicative questions were formed, of which 68 entered the modified Delphi process. Eleven 'highest priority' research questions were short listed, covering themes of pain management; training and assessment; clinical practice and efficacy; technology and equipment. CONCLUSIONS: We prioritised unanswered research questions in regional anaesthesia. These will inform a coordinated global research strategy for regional anaesthesia and direct investigators to address high-priority areas.

Artificial intelligence for ultrasound scanning in regional anaesthesia: a scoping review of the evidence from multiple disciplines.

BACKGROUND: Artificial intelligence (AI) for ultrasound scanning in regional anaesthesia is a rapidly developing interdisciplinary field. There is a risk that work could be undertaken in parallel by different elements of the community but with a lack of knowledge transfer between disciplines, leading to repetition and diverging methodologies. This scoping review aimed to identify and map the available literature on the accuracy and utility of AI systems for ultrasound scanning in regional anaesthesia. METHODS: A literature search was conducted using Medline, Embase, CINAHL, IEEE Xplore, and ACM Digital Library. Clinical trial registries, a registry of doctoral theses, regulatory authority databases, and websites of learned societies in the field were searched. Online commercial sources were also reviewed. RESULTS: In total, 13,014 sources were identified; 116 were included for full-text review. A marked change in AI techniques was noted in 2016-17, from which point on the predominant technique used was deep learning. Methods of evaluating accuracy are variable, meaning it is impossible to compare the performance of one model with another. Evaluations of utility are more comparable, but predominantly gained from the simulation setting with limited clinical data on efficacy or safety. Study methodology and reporting lack standardisation. CONCLUSIONS: There is a lack of structure to the evaluation of accuracy and utility of AI for ultrasound scanning in regional anaesthesia, which hinders rigorous appraisal and clinical uptake. A framework for consistent evaluation is needed to inform model evaluation, allow comparison between approaches/models, and facilitate appropriate clinical adoption.

Regional anaesthesia education for consultants and specialists in the UK: a mixed-methods analysis.

BACKGROUND: Regional anaesthesia plays an important role in perioperative care, but gaps in proficiency persist among consultants and specialists. This study aimed to assess confidence levels in performing Plan A blocks among this cohort and to examine the barriers and facilitators influencing regional anaesthesia education. METHODS: Utilising a mixed-methods design, we performed a quantitative survey to gauge self-reported confidence in performing Plan A blocks, coupled with qualitative interviews to explore the complexities of educational barriers and facilitators. UK consultant and specialist anaesthetists were included in the study. RESULTS: A total of 369 survey responses were analysed. Only 22% of survey respondents expressed confidence in performing all Plan A blocks. Specialists (odds ratio [OR] 0.391, 95% confidence interval [CI] 0.179-0.855, P=0.016) and those in their roles for >10 yr (OR 0.551, 95% CI 0.327-0.927, P = 0.024) reported lower confidence levels. A purposive sample was selected for interviews, and data saturation was reached at 31 interviews. Peer-led learning emerged as the most effective learning modality for consultants and specialists. Barriers to regional anaesthesia education included apprehensions regarding complications, self-perceived incompetence, lack of continuing professional development time, insufficient support from the multidisciplinary team, and a lack of inclusivity within the regional anaesthesia community. Organisational culture had a substantial impact, with the presence of local regional anaesthesia champions emerging as a key facilitator. CONCLUSIONS: This study highlights persistent perceived deficiencies in regional anaesthesia skills among consultants and specialists. We identified multiple barriers and facilitators, providing insights for targeted interventions aimed at improving regional anaesthesia education in this group.

Noninferiority trials in acute pain research: a valid approach or a slippery slope?

The conduct and reporting of studies with a noninferiority hypothesis is challenging because of the complexity involved in their design and interpretation. However, studies with a noninferiority design have increased in popularity. A recently published trial reported on the noninferiority of lidocaine infusion to epidural analgesia in major abdominal surgeries. Apart from needing a critical appraisal, this draws attention to improve our understanding of noninferiority study framework and its unique features. Given the increasing focus on using various analgesic adjuncts and multiple approaches to fascial plane blocks to avoid more definitive and standard approaches, it is imperative that particular attention is paid to appropriate execution and reporting of noninferiority studies.

Nerve block, nerve damage, and fluid injection pressure: overturning the myth.

Histological and micro-ultrasound evidence rebuffs deep-rooted views on the nature of nerve block, nerve damage, and injection pressure monitoring. We propose that the ideal position of the needle tip for nerve block is between the innermost circumneural fascial layer and outer epineurium, with local anaesthetic passing circumferentially through adipose tissue. Thin, circumferential, subepineural expansion that is invisible to the naked eye was identified using micro-ultrasound, and could account for variability of outcomes in clinical practice. Pressure monitoring cannot differentiate between intrafascicular and extrafascicular injection. High injection pressure only indicates intraneural extrafascicular spread, not intrafascicular spread, because it is not possible to inject into the stiff endoneurium in most human nerves.

Regional anaesthesia truncal blocks for acute postoperative pain and recovery: a narrative review.

Significant acute postoperative pain remains prevalent among patients who undergo truncal surgery and is associated with increased morbidity, prolonged patient recovery, and increased healthcare costs. The provision of high-quality postoperative analgesia is an important component of postoperative care, particularly within enhanced recovery programmes. Regional anaesthetic techniques have become increasingly prevalent within multimodal analgesic regimens and the widespread adoption of ultrasonography has facilitated the development of novel fascial plane blocks. The number of described fascial plane blocks has increased significantly over the past decade, leading to a burgeoning area of clinical investigation. Their applications are increasing, and truncal fascial plane blocks are increasingly recommended as part of procedure-specific guidelines. Some fascial plane blocks have been shown to be more efficacious than others, with favourable side-effect profiles compared with neuraxial analgesia, and are increasingly utilised in breast, thoracic, and other truncal surgery. However, use of these blocks is debated in regional anaesthesia circles because of limitations in our understanding of their mechanisms of action. This narrative review evaluates available evidence for the analgesic efficacy of the most commonly practised fascial plane blocks in breast, thoracic, and abdominal truncal surgery, in particular their efficacy compared with systemic analgesia, alternative blocks, and neuraxial techniques. We also highlight areas where investigations are ongoing and suggest priorities for original investigations.

Leading in the development, standardised evaluation, and adoption of artificial intelligence in clinical practice: regional anaesthesia as an example.

A recent study by Suissa and colleagues explored the clinical relevance of a medical image segmentation metric (Dice metric) commonly used in the field of artificial intelligence (AI). They showed that pixel-wise agreement for physician identification of structures on ultrasound images is variable, and a relatively low Dice metric (0.34) correlated to a substantial agreement on subjective clinical assessment. We highlight the need to bring structure and clinical perspective to the evaluation of medical AI, which clinicians are best placed to direct.

Craniocaudal spread and clinical translation for combined erector spinae plane block and retrolaminar block in soft embalmed cadavers: a randomised controlled equivalence study.

BACKGROUND: Erector spinae plane (ESP) block spread can be unpredictable. We previously improved the spread of ESP injection by addition of retrolaminar (RL) injection. However, it is not clear whether spread at high thoracic levels is similar to spread at midthoracic levels. Our primary objective was to demonstrate that craniocaudal dye spread was equivalent after combined ESP and RL injection using a 19 G Tuohy needle at the third (T3) and sixth (T6) vertebrae in soft embalmed Thiel cadavers. METHODS: We randomised 20 combined ESP and RL injections to the T3 and T6 vertebral levels on both sides of 10 prone Thiel cadavers. A 3-8 MHz transducer was placed in the paramedian sagittal plane and a single anaesthetist injected 10 ml dye onto the transverse process, then 10 ml dye onto the laminae of T3 or T6. Cadavers were dissected 24 h later. RESULTS: Mean (sd) craniocaudal spread of dye after combined ESP + RL injection at T3 and T6 vertebral levels was equivalent: 8.6 (1.8) vs 8.7 (2.3) levels, respectively; difference (90% confidence interval): -0.1 (-1.4 to 1.6), P=0.904. Dye extended uniformly, cranially and caudally, from the point of injection. A 3D prosection created from a Thiel cadaver confirmed that the dorsal ramus emerges from the costotransverse foramen deep to the intertransverse ligament within the retro-superior costotransverse ligament space. Combined ESP and RL block in six patients before mastectomy achieved extensive anterior, lateral, and posterior chest wall paraesthesia over four to six dermatomes. CONCLUSIONS: Combined ESP and RL injections showed equivalent and consistent spread at T3 and T6 injection sites. A pilot study confirmed translation to patients.

Development and validation of metrics for assessment of ultrasound-guided fascial block skills☆.

BACKGROUND: As few anaesthetists provide lumbar erector spinae block for disc surgery, there is a need to provide training to enable a randomised controlled trial investigating analgesia after painful spinal surgery (NIHR153170). The primary objective of the study was to develop and measure the construct validity of a checklist for assessment of skills in performing lumbar and thoracic erector spinae fascial plane injection using soft-embalmed Thiel cadavers. METHODS: Twenty-four UK consultant regional anaesthetists completed two iterations of a Delphi questionnaire. The final checklist consisted of 11 steps conducive to best practice. Thereafter, we validated the checklist by comparing the performance of 12 experts with 12 novices, each performing lumbar and thoracic erector spinae plane injections or fascia iliaca, serrato-pectoral (PEC II) and serratus injections, randomly allocated to the left and right sides of six soft-embalmed Thiel cadavers. Six expert, trained raters blinded to operator and site of block examined 120 videos each. RESULTS: The mean (95% confidence interval) internal consistency of the 11-item checklist for erector spinae plane injection was 0.72 (0.63-0.79) and interclass correlation was 0.88 (0.82-0.93). The checklist showed construct validity for lumbar and thoracic erector spinae injection, experts vs novices {median (interquartile range [range]) 8.0 (7.0-10.0 [1-11]) vs 7.0 (5.0-9.0 [4-11]), difference 1.5 (1.0-2.5), P<0.001}. Global rating scales showed construct validity for lumbar and thoracic erector spinae injection, 28.0 (24.0-31.0 [7-35]) vs 21.0 (17.0-24.0 [7-35]), difference 7.5 (6.0-8.5), P<0.001. The most difficult items to perform were identifying the needle tip before advancing and always visualising the needle tip. Instrument handling and flow of procedure were the areas of greatest difficulty on the global rating scale (GRS). Checklists and GRS scores correlated. There was homogeneity of regression slopes controlling for status, type of injection, and rater. Generalisability analysis showed a high reliability using the checklist and GRS for all fascial plane blocks (Rho [ρ2] 0.93-0.96: Phi [ϕ] 0.84-0.87). CONCLUSIONS: An 11-point checklist developed through a modified Delphi process to provide best practice guidance for fascial plane injection showed construct validity in performing lumbar and thoracic erector spinae fascial plane injection in soft-embalmed Thiel cadavers.

Ultrasound-guided suprainguinal fascia iliaca compartment block and early postoperative analgesia after total hip arthroplasty: a randomised controlled trial.

BACKGROUND: Hip replacement surgery can be painful; postoperative analgesia is crucial for comfort and to facilitate recovery. Regional anaesthesia can reduce pain and postoperative opioid requirements. The role of ultrasound-guided suprainguinal fascia iliaca block for analgesia after elective total hip arthroplasty is not well defined. This randomised trial evaluated its analgesic efficacy. METHODS: Consenting participants (134) scheduled for elective primary total hip arthroplasty under spinal anaesthesia were randomly allocated to receive ultrasound-guided fascia iliaca block with ropivacaine 0.5% or sham block with saline. The primary outcome was opioid consumption in the first 24 h after surgery. Additional outcomes included pain scores at 4, 8, 12, and 16 h, opioid-related side-effects (nausea, vomiting, pruritis), ability to perform physiotherapy on the first postoperative day, and physiotherapist-assessed quadriceps weakness. RESULTS: There were no significant differences in 24-h opioid consumption (block vs sham block, mean difference -3.2 mg oral morphine equivalent, 95% confidence interval -15.3 to 8.1 mg oral morphine equivalent, P=0.55) or any other prespecified outcomes. CONCLUSIONS: In patients undergoing primary total hip arthroplasty, ultrasound-guided suprainguinal fascia iliaca block with ropivacaine did not confer a significant opioid-sparing effect compared with sham block. There were no differences in other secondary outcomes including pain scores, opioid-related side-effects, or ability to perform physiotherapy on the first postoperative day. CLINICAL TRIAL REGISTRATION: www. CLINICALTRIALS: gov (NCT03069183).

Attaining expertise in regional anaesthesia training using a multifactorial approach incorporating deliberate practice.

The most effective way of delivering regional anaesthesia training and the best means of demonstrating competency have not been established. Clinical competency, based on the Dreyfus and Dreyfus lexicon, appears unachievable using current training approaches. Lessons should be taken from the worlds of music, chess, and sports. Modern skills training programmes should be built on an explicit and detailed understanding with measurement of a variety of factors such as perception, attention, psychomotor and visuospatial function, and kinesthetics, coupled with quantitative, accurate, and reliable measurement of performance.

Research priorities in regional anaesthesia: where should we focus?

Using a modified Delphi technique, an international group of regional anaesthetists generated a list of top research priorities in regional anaesthesia. The list of unanswered research questions was created from a questionnaire completed by >500 anaesthetists and distilled into 11 priorities grouped into four themes: clinical practice and efficacy, pain management, technology and equipment, and training and assessment.

Defining the optimal local anaesthetic infusion regimen for erector spinae plane block catheters: the devil is in the details.

Ni Eochagain and colleagues report that programmed intermittent bolus and continuous infusion regimens in continuous erector spinae plane (ESP) block catheters produced similar quality of recovery (QoR-15) scores, pain scores, and use of rescue opioids after video-assisted thoracic surgery. This is a reassuring finding for practitioners without access to pumps with programmed intermittent bolus functionality. Nevertheless, it remains plausible that the benefit of one regimen over another might vary depending on the specific infusion parameters. There continues to be scope for research into optimising programmed intermittent bolus delivery and dosing regimens and identifying the most appropriate clinical applications for this mode of infusion.

Programmed intermittent bolus versus continuous infusion for catheter-based erector spinae plane block on quality of recovery in thoracoscopic surgery: a single-centre randomised controlled trial.

BACKGROUND: Regional anaesthesia techniques, including the erector spinae fascial plane (ESP) block, reduce postoperative pain after video-assisted thoracoscopic surgery (VATS). Fascial plane blocks rely on spread of local anaesthetic between muscle layers, and thus, intermittent boluses might increase their clinical effectiveness. We tested the hypothesis that postoperative ESP analgesia with a programmed intermittent bolus (PIB) regimen is better than a continuous infusion (CI) regimen in terms of quality of recovery after VATS. METHODS: We undertook a prospective, double-blinded, randomised, controlled trial involving 60 patients undergoing VATS. All participants received ESP block catheters and were randomly assigned to CI or PIB of local anaesthetic regimen for postoperative analgesia. The primary outcome was Quality of Recovery-15 (QoR-15) score 24 h after surgery. Secondary outcomes included postoperative respiratory function, opioid consumption, verbal rating pain score, time to first mobilisation, nausea, vomiting, and length of hospital stay. RESULTS: Overall QoR-15 scores at 24 h after VATS were similar (PIB 115.5 [interquartile range 107-125] vs CI 110 [93-128]; Δ<6, P=0.29). The only quality of recovery descriptor showing a significant difference was nausea and vomiting, which was favourable in the PIB group (10 [10-10] vs 10 [7-10]; P=0.03). Requirement for rescue antiemetics up to 24 h after surgery was lower in the PIB group (4 [14%] vs 11 [41%]; P=0.04). There were no differences in other secondary outcomes between groups. CONCLUSIONS: Delivering ESP block analgesia after VATS via a PIB regimen resulted in similar QoR-15 at 24 h compared with a CI regimen.