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.

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.

Regional analgesia for total hip arthroplasty and Schwartz's paradox.

Enhanced recovery after total hip arthroplasty aims to facilitate return to function and early hospital discharge, but the role of novel fascial plane block techniques in such pathways is uncertain. A randomised trial by Kukreja and colleagues describes superior quality of recovery after hip arthroplasty in patients receiving a pericapsular nerve group (PENG) block. We discuss the trial findings in the context of ongoing uncertainty regarding best analgesic practice for this surgical procedure.

Evaluation of the impact of assistive artificial intelligence on ultrasound scanning for regional anaesthesia.

BACKGROUND: Ultrasound-guided regional anaesthesia relies on the visualisation of key landmark, target, and safety structures on ultrasound. However, this can be challenging, particularly for inexperienced practitioners. Artificial intelligence (AI) is increasingly being applied to medical image interpretation, including ultrasound. In this exploratory study, we evaluated ultrasound scanning performance by non-experts in ultrasound-guided regional anaesthesia, with and without the use of an assistive AI device. METHODS: Twenty-one anaesthetists, all non-experts in ultrasound-guided regional anaesthesia, underwent a standardised teaching session in ultrasound scanning for six peripheral nerve blocks. All then performed a scan for each block; half of the scans were performed with AI assistance and half without. Experts assessed acquisition of the correct block view and correct identification of sono-anatomical structures on each view. Participants reported scan confidence, experts provided a global rating score of scan performance, and scans were timed. RESULTS: Experts assessed 126 ultrasound scans. Participants acquired the correct block view in 56/62 (90.3%) scans with the device compared with 47/62 (75.1%) without (P=0.031, two data points lost). Correct identification of sono-anatomical structures on the view was 188/212 (88.8%) with the device compared with 161/208 (77.4%) without (P=0.002). There was no significant overall difference in participant confidence, expert global performance score, or scan time. CONCLUSIONS: Use of an assistive AI device was associated with improved ultrasound image acquisition and interpretation. Such technology holds potential to augment performance of ultrasound scanning for regional anaesthesia by non-experts, potentially expanding patient access to these techniques. CLINICAL TRIAL REGISTRATION: NCT05156099.

The practice of regional anesthesia during the COVID-19 pandemic: an international survey of members of three regional anesthesia societies.

PURPOSE: To determine the preferences and attitudes of members of regional anesthesia societies during the COVID-19 pandemic. METHODS: We distributed an electronic survey to members of the American Society of Regional Anesthesia and Pain Medicine, Regional Anaesthesia-UK, and the European Society of Regional Anaesthesia & Pain Therapy. A questionnaire consisting of 19 questions was developed by a panel of experienced regional anesthesiologists and distributed by email to the participants. The survey covered the following domains: participant information, practice settings, preference for the type of anesthetic technique, the use of personal protective equipment, and oxygen therapy. RESULTS: The survey was completed by 729 participants from 73 different countries, with a response rate of 20.1% (729/3,630) for the number of emails opened and 8.5% (729/8,572) for the number of emails sent. Most respondents (87.7%) identified as anesthesia staff (faculty or consultant) and practiced obstetric and non-obstetric anesthesia (55.3%). The practice of regional anesthesia either expanded or remained the same, with only 2% of respondents decreasing their use compared with the pre-pandemic period. The top reasons for an increase in the use of regional anesthesia was to reduce the need for an aerosol-generating medical procedure and to reduce the risk of possible complications to patients. The most common reason for decreased use of regional anesthesia was the risk of urgent conversion to general anesthesia. Approximately 70% of the responders used airborne precautions when providing care to a patient under regional anesthesia. The most common oxygen delivery method was nasal prongs (cannula) with a surgical mask layered over it (61%). CONCLUSIONS: Given the perceived benefits of regional over general anesthesia, approximately half of the members of three regional anesthesia societies seem to have expanded their use of regional anesthesia techniques during the initial surge of the COVID-19 pandemic.

RéSUMé: OBJECTIF: Déterminer les préférences et les attitudes des membres des sociétés d'anesthésie régionale pendant la pandémie de COVID-19. MéTHODE: Nous avons distribué un sondage électronique aux membres de l'American Society of Regional Anesthesia and Pain Medicine, de Regional Anesthesia-UK et de l'European Society of Regional Anaesthesia & Pain Therapy. Un questionnaire composé de 19 questions a été élaboré par un panel d'anesthésiologistes régionaux d'expérience et distribué par courriel aux participants. Le sondage couvrait les domaines suivants : les renseignements sur les participants, les contextes de pratique, leur préférence quant au type de technique d'anesthésie, l'utilisation d'équipement de protection individuelle et l'oxygénothérapie RéSULTATS: Le sondage a été complété par 729 participants provenant de 73 pays différents, avec un taux de réponse de 20,1 % (729/3630) pour le nombre de courriels ouverts et de 8,5 % (729/8572) pour le nombre de courriels envoyés. La plupart des répondants (87,7 %) se sont identifiés comme anesthésiologistes (académique ou consultant) et pratiquaient l'anesthésie obstétricale et non obstétricale (55,3 %). Leur pratique de l'anesthésie régionale s'est étendue ou est demeurée inchangée, et seulement 2 % des répondants ont indiqué avoir diminué leur utilisation de cette pratique par rapport à la période pré-pandémique. Les principales raisons d'une augmentation de l'utilisation de l'anesthésie régionale étaient de réduire la nécessité d'une intervention médicale générant des aérosols et de réduire le risque de complications potentielles pour les patients. La raison la plus courante de diminution du recours à l'anesthésie régionale était le risque de conversion urgente à une anesthésie générale. Environ 70 % des intervenants ont utilisé des précautions en matière de propagation des aérosols lorsqu'ils procuraient des soins à un patient sous anesthésie régionale. La méthode d'administration d'oxygène la plus fréquemment utilisée était les canules nasales avec un masque chirurgical superposé (61 %). CONCLUSION: Compte tenu des avantages perçus de l'anesthésie régionale par rapport à l'anesthésie générale, environ la moitié des membres de trois sociétés d'anesthésie régionale semblent avoir élargi leur utilisation des techniques d'anesthésie régionale pendant la vague initiale de la pandémie de COVID-19.

Regional anesthesia for vascular surgery: does the anesthetic choice influence outcome?

PURPOSE OF REVIEW: Outcomes following surgery are of major importance to clinicians, institutions and most importantly patients. This review examines whether regional anesthesia and analgesia influence outcome after vascular surgery. RECENT FINDINGS: Large database analyses of contemporary practice suggest that utilizing regional anesthesia for both open and endovascular aortic aneurysm repair, lower limb revascularization and carotid endarterectomy reduces morbidity, length of stay and possibly even mortality. Results from such analyses are limited by an inherent risk of bias but are nevertheless important given the number of patients required in randomized trials to detect differences in rare outcomes. There is minimal evidence that regional anesthesia influences longer term outcomes except for arteriovenous fistula surgery where brachial plexus blocks appear to improve 3-month fistula patency. SUMMARY: Patients undergoing vascular surgery often have multiple comorbidities and it is important to be able to outline both benefits and risks of regional anesthesia techniques. Regional anesthesia in vascular surgery allows avoidance of general anesthesia and does provide short-term benefits beyond superior analgesia. Evidence of long-term benefits is lacking in most procedures. Further work is required on newer patient centered outcomes.

A systematic review of mechanical thromboprophylaxis in the lithotomy position.

BACKGROUND: Venous thrombosis and compartment syndrome are potentially serious complications of prolonged, lithotomy position surgery. It is unclear whether mechanical thromboprophylaxis in this group of patients modifies the risk of compartment syndrome. This qualitative systematic review examines the evidence base to guide clinical practice. METHOD: A systematic review was performed guided by Preferred Reporting Items for Systematic reviews and Meta-Analyses (PRISMA) criteria, to identify studies reporting relationships between lithotomy position, compartment syndrome and mechanical thromboprophylaxis. The aim was to determine if mechanical thromboprophylaxis influenced compartment syndrome risk in the lithotomy position. RESULTS: Sixteen studies were identified: eight case reports or case series (12 patients), two completed audit cycles (approximately 2000 patients), four reviews and two volunteer case control studies (33 subjects). There were no randomised studies. Nine studies associated mechanical thromboprophylaxis with compartment syndrome risk but in each case a causative relationship was speculative. In contrast, five papers, including an experimental, cohort study and two observational, population studies recommended intermittent pneumatic compression as prevention against compartment syndrome in lithotomy position. One review and one case report were unable to make a recommendation. CONCLUSIONS: The level of evidence addressing the interaction between the lithotomy position, compartment syndrome and mechanical thromboprophylaxis is weak. There is no conclusive evidence that mechanical thromboprophylaxis causes compartment syndrome in the lithotomy position. There is limited evidence to suggest intermittent pneumatic compression may be a safe method of mechanical thromboprophylaxis if accompanied by strict adherence to other measures to reduce the chance of compartment syndrome. However further studies are required.

Prospective randomized evaluation of the sustained impact of assistive artificial intelligence on anesthetists' ultrasound scanning for regional anesthesia.

Objectives: Ultrasound-guided regional anesthesia (UGRA) relies on acquiring and interpreting an appropriate view of sonoanatomy. Artificial intelligence (AI) has the potential to aid this by applying a color overlay to key sonoanatomical structures.The primary aim was to determine whether an AI-generated color overlay was associated with a difference in participants' ability to identify an appropriate block view over a 2-month period after a standardized teaching session (as judged by a blinded assessor). Secondary outcomes included the ability to identify an appropriate block view (unblinded assessor), global rating score and participant confidence scores. Design: Randomized, partially blinded, prospective cross-over study. Setting: Simulation scans on healthy volunteers. Initial assessments on 29 November 2022 and 30 November 2022, with follow-up on 25 January 2023 - 27 January 2023. Participants: 57 junior anesthetists undertook initial assessments and 51 (89.47%) returned at 2 months. Intervention: Participants performed ultrasound scans for six peripheral nerve blocks, with AI assistance randomized to half of the blocks. Cross-over assignment was employed for 2 months. Main outcome measures: Blinded experts assessed whether the block view acquired was acceptable (yes/no). Unblinded experts also assessed this parameter and provided a global performance rating (0-100). Participants reported scan confidence (0-100). Results: AI assistance was associated with a higher rate of appropriate block view acquisition in both blinded and unblinded assessments (p=0.02 and <0.01, respectively). Participant confidence and expert rating scores were superior throughout (all p<0.01). Conclusions: Assistive AI was associated with superior ultrasound scanning performance 2 months after formal teaching. It may aid application of sonoanatomical knowledge and skills gained in teaching, to support delivery of UGRA beyond the immediate post-teaching period. Trial registration number: www.clinicaltrials.govNCT05583032.

Regional anaesthesia training in the UK - a national survey.

Background: Adequate training of anaesthetists in regional anaesthesia is important to ensure optimal patient access to regional anaesthesia. Methods: We undertook a national survey of UK trainee anaesthetists and Royal College of Anaesthetists (RCoA) tutors to assess experiences of training in regional anaesthesia. We performed descriptive statistics for baseline characteristics, and logistic regression of training indices and tutor confidence that their hospital could provide regional anaesthesia training at all three stages of the RCoA 2021 curriculum. Results: A total of 492 trainees (19.2%) and 114 tutors (45.2%) completed the survey. Trainees were less likely to have received training in chest/abdominal wall compared with upper/lower limb blocks {erector spinae vs femoral block (odds ratio [OR] 0.25, 95% confidence interval [CI] 0.16-0.39), P<0.001}, or achieved >20 chest/abdominal wall blocks by Stage 3 of training (chest vs lower limb block [OR 0.09, 95% CI 0.05-0.15, P<0.001]. There was a strong association between training received, number of blocks performed (>20 vs 0-5 blocks), and self-reported ability to perform blocks independently, OR 20.9 (95% CI 9.38-53.2). 24/182 (13%) and 10/182 (5.5%) of trainees had performed ≥50 non-obstetric lumbar and thoracic epidurals, respectively, by Stage 3 training. There was a positive association between having a lead clinician for regional anaesthesia, particularly those with paid sessions, and reported confidence to provide regional anaesthesia training at all stages of the curriculum (Stage 3 OR 7.27 [95% CI 2.64-22.0]). Conclusion: Our results confirm the importance of clinical experience and access to training in regional anaesthesia, and support the introduction of departmental regional anaesthesia leads to improve equity and quality in training opportunities.

Does regional anesthesia improve outcome after total knee arthroplasty?

Total knee arthroplasty (TKA) is amenable to various regional anesthesia techniques that may improve patient outcome. We sought to answer whether regional anesthesia decreased mortality, cardiovascular morbidity, deep venous thrombosis and pulmonary embolism, blood loss, duration of surgery, pain, opioid-related adverse effects, cognitive defects, and length of stay. We also questioned whether regional anesthesia improved rehabilitation. To do so, we performed a systematic review of the contemporary literature comparing general anesthesia and/or systemic analgesia with regional anesthesia and/or regional analgesia for TKA. To reflect contemporary surgical and anesthetic practice, only randomized, controlled trials from 1990 onward were included. We identified 28 studies involving 1538 patients. There was insufficient evidence from randomized, controlled trials alone to conclude if anesthetic technique influenced mortality, cardiovascular morbidity other than postoperative hypotension, or the incidence of deep venous thrombosis and pulmonary embolism when using thromboprophylaxis. Our review suggests there was no difference in perioperative blood loss or duration of surgery in patients who received general anesthesia versus regional anesthesia. Compared with general anesthesia and/or systemic analgesia, regional anesthesia and/or analgesia reduced postoperative pain, morphine consumption, and opioid-related adverse effects. Length of stay may be reduced and rehabilitation facilitated for patients undergoing regional anesthesia and analgesia for TKA.

Randomised controlled trial of combined spinal epidural vs. spinal anaesthesia for elective caesarean section: vasopressor requirements and cardiovascular changes.

BACKGROUND AND OBJECTIVES: Combined spinal and epidural anaesthesia (CSEA) has previously been shown to result in a higher sensory block than equivalent single shot spinal anaesthesia (SSSA). In nonpregnant patients, hypotension was also more pronounced in the CSEA group. The aim of this randomized trial was to compare the haemodynamic stabilities of CSEA and SSSA during elective caesarean section when the same dose of anaesthetic was administered. This was studied directly by measuring the noninvasive arterial blood pressure (BP) and indirectly by the amount of ephedrine required to maintain baseline BP. Systemic vascular resistance index (SVRI) and cardiac index (CI) were also measured using thoracic impedance cardiography. METHODS: Seventy women received hyperbaric bupivacaine (12.5 mg) and diamorphine (0.3 mg) intrathecally via either CSEA or SSSA. Noninvasive arterial BP, CI and SVRI were measured every 2 min. The total ephedrine used was calculated. RESULTS: There were no significant differences between the groups in ephedrine requirements (P = 0.38), intraoperative mean arterial pressure (P = 0.77), CI (P = 0.17) or SVRI (P = 0.10). CONCLUSION: CSEA placement appears to offer no haemodynamic benefits compared with SSSA when the same dose of local anaesthetic is administered.

The use of ultrasound to facilitate spinal anesthesia in a patient with previous lumbar laminectomy and fusion: a case report.

We describe a case of ultrasound (US)-facilitated spinal anesthesia in a patient with a prior lumbar laminectomy and spinal fusion who presented for total knee arthroplasty. Traditional, landmark-guided spinal anesthesia had previously failed. Although pre-procedural US identified a soft-tissue window at L3/4, a 25G pencilpoint needle encountered resistance. Reassured from US imaging that this was not bone, we used a 22G cutting tip needle successfully. We believe spinal anesthesia would not have been possible in this patient without US, adding to the evidence that US-facilitated neuraxial anesthesia is useful, particularly in technically difficult, if not 'impossible,' cases.

The Requisites of Needle-to-Nerve Proximity for Ultrasound-Guided Regional Anesthesia: A Scoping Review of the Evidence.

This scoping review examines the literature to determine whether the position of the needle tip relative to the target nerve is accurately and reliably detected during ultrasound (US)-guided regional anesthesia. The requisites for successful and safe needle tip positioning relative to the target nerve include accurate and reliable needle presentation by the machine, needle interpretation by the operator, nerve presentation by the machine, and nerve interpretation by the operator. Failure to visualize the needle tip is a common occurrence, frequently prompting operators to use needle and probe maneuvers, which are not necessarily based on evidence. Needle tip interpretation often relies on surrogate indicators that have not been validated. The acoustic resolution of modern portable US machines limits the extent to which nerve microanatomy can be reliably presented. Finally, our interpretation of the sonographic end points for local anesthetic injection that best balance success and safety for US-guided regional anesthesia continues to evolve. WHAT'S NEW: In order to determine whether or not the position of the needle tip relative to the target nerve is accurately and reliably detected during US-guided regional anesthesia, the available literature is reviewed and interpreted to address the following 4 questions.

Effect of body mass index on angle of needle insertion during ultrasound-guided lateral sagittal infraclavicular brachial plexus block.

STUDY OBJECTIVES: The aim of our study was to establish the angle of needle insertion from the anterior chest wall during ultrasound-guided infraclavicular brachial plexus block and to examine for any correlation between body mass index (BMI) and insertion angle. DESIGN: This is a prospective observational study. SETTING: The setting is at an operating room, university-affiliated teaching hospital. PATIENTS: The patients are 23 American Society of Anesthesiologists physical status 1-3 patients scheduled to undergo elbow, forearm, or hand surgery under regional anesthesia with or without general anesthesia. INTERVENTIONS: The intervention is infraclavicular brachial plexus block with or without perineural catheter insertion. MEASUREMENTS: The measurement is the angle of needle insertion in relation to the anterior chest wall, BMI, and needle visibility as graded by the anesthesiologist. MAIN RESULTS: Twenty-three patients were studied. The mean (SD) BMI was 28.5 (5.4). The median (range) of angle of needle insertion was 50 (33-60). The Pearson correlation coefficient for BMI and angle of needle insertion was 0.357. There were no reported complications. CONCLUSIONS: The median (range) angle of needle insertion in relation to chest for our study patients was 50° (33°-60°). The needle visibility was rated difficult, requiring hydrolocation or "heeling-in," in 39% of cases. There was a moderate correlation between BMI and angle of insertion. Despite difficulties with needle visualization, the ultrasound-guided infraclavicular brachial plexus block provided reliable analgesia.

Intrathecal opioid versus ultrasound guided fascia iliaca plane block for analgesia after primary hip arthroplasty: study protocol for a randomised, blinded, noninferiority controlled trial.

BACKGROUND: Hip replacement surgery is increasingly common due to an ageing population, and rising levels of obesity. The provision of excellent pain relief with minimal side effects is important in order to facilitate patient mobilisation and rehabilitation.Spinal opioids provide excellent analgesia but are associated with adverse effects. The fascia-iliaca block is an alternative technique which provides analgesia to the nerves innervating the hip. The success of fascia iliaca blocks has been demonstrated to be superior when using ultrasound compared to landmark techniques. However, the clinical benefit of this improvement has yet to be investigated.The aim of this study is to compare the efficacy and safety of ultrasound guided fascia iliaca block with spinal morphine for hip replacement surgery. METHODS/DESIGN: This study is a randomised, blinded, placebo-controlled, noninferiority trial. Patients scheduled to undergo unilateral primary hip arthroplasty will receive a study information sheet and consent will be obtained in keeping with the Declaration of Helsinki. Patients will be randomised to receive either; (i) Ultrasound guided fascia iliaca block using levobupivacaine, plus spinal anaesthesia with hyperbaric bupivacaine containing no morphine, or (ii) sham ultrasound guided fascia iliaca block performed with sterile saline, and spinal anaesthesia containing hyperbaric bupivacaine and 0.1 mg of spinal morphine.A total of 108 patients will be recruited. Primary outcome is post-operative morphine consumption in a 24 hour period. Secondary outcomes include; pain scores at 3, 6, 12, 24, 36 and 48 hours, episodes of respiratory depression, hypotension, nausea and vomiting, pruritus, sedation, time to first mobilisation and patient satisfaction. CONCLUSIONS: There are no studies to date comparing ultrasound guided fascia iliaca block with spinal morphine for pain control after hip arthroplasty. If the ultrasound guided fascia iliaca block provides pain relief which is not inferior to spinal morphine, then morphine could be removed from the spinal injection. This could reduce side effects and improve patient safety. TRIAL REGISTRATION: This study has been approved by the West of Scotland Research Ethics Committee 4 (reference no. 10/S0704/43) and is registered with ClinicalTrials.gov (reference no. NCT01217294).