Factors to consider for fascial plane blocks' success in acute and chronic pain management

The outcome of fascial plane blocks (FPBs) has a certain variability that may depend on many factors, which can be divided into three main categories: operator-related, patient-related and drug-related. Operator-related factors include personal skills, choice of needle and injection modalities. Patient variables include anthropometric features, the type of targeted fascia, anatomical variants, patient positioning, muscle tone and breathing. Ultimately, efficacy, onset, and duration of fascial blocks may be affected by characteristics of the injected solution, including the type of local anesthetic, volume, concentration, pH, temperature and the use of adjuvants. In this article, we investigated all the factors that may influence the outcome of FPBs from a generic perspective, without focusing on any specific technique. Also, we provided suggestions to optimize techniques for everyday practitioners and insights to researchers for future studies.

Standardizing nomenclature in regional anesthesia: an ASRA-ESRA Delphi consensus study of upper and lower limb nerve blocks

BACKGROUND

Inconsistent nomenclature and anatomical descriptions of regional anesthetic techniques hinder scientific communication and engender confusion; this in turn has implications for research, education and clinical implementation of regional anesthesia. Having produced standardized nomenclature for abdominal wall, paraspinal and chest wall regional anesthetic techniques, we aimed to similarly do so for upper and lower limb peripheral nerve blocks.

METHODS

We performed a three-round Delphi international consensus study to generate standardized names and anatomical descriptions of upper and lower limb regional anesthetic techniques. A long list of names and anatomical description of blocks of upper and lower extremities was produced by the members of the steering committee. Subsequently, two rounds of anonymized voting and commenting were followed by a third virtual round table to secure consensus for items that remained outstanding after the first and second rounds. As with previous methodology, strong consensus was defined as ≥75% agreement and weak consensus as 50%-74% agreement.

RESULTS

A total of 94, 91 and 65 collaborators participated in the first, second and third rounds, respectively. We achieved strong consensus for 38 names and 33 anatomical descriptions, and weak consensus for five anatomical descriptions. We agreed on a template for naming peripheral nerve blocks based on the name of the nerve and the anatomical location of the blockade and identified several areas for future research.

CONCLUSIONS

We achieved consensus on nomenclature and anatomical descriptions of regional anesthetic techniques for upper and lower limb nerve blocks, and recommend using this framework in clinical and academic practice. This should improve research, teaching and learning of regional anesthesia to eventually improve patient care.

Erector spinae plane block: the ultimate 'plan A' block?

The erector spinae plane block (ESPB) is one of seven 'Plan A' blocks proposed by Regional Anaesthesia UK, covering the key areas of commonly encountered surgeries and acute pain. Unlike the other six blocks, the ESPB can be performed at all levels of the spine and provides analgesia to most regions of the body, leading to the argument that the ESPB is the ultimate Plan A block. Current studies show a high level of evidence supporting use in thoracoabdominal surgery but a lack of benefit in upper and lower limb surgery compared with local infiltration and other Plan A blocks. Thus, there is insufficient evidence to support the claim that the erector spinae plane block is the ultimate Plan A block.

Assistive artificial intelligence for ultrasound image interpretation in regional anaesthesia: an external validation study

BACKGROUND

Ultrasonound is used to identify anatomical structures during regional anaesthesia and to guide needle insertion and injection of local anaesthetic. ScanNav Anatomy Peripheral Nerve Block (Intelligent Ultrasound, Cardiff, UK) is an artificial intelligence-based device that produces a colour overlay on real-time B-mode ultrasound to highlight anatomical structures of interest. We evaluated the accuracy of the artificial-intelligence colour overlay and its perceived influence on risk of adverse events or block failure.

METHODS

Ultrasound-guided regional anaesthesia experts acquired 720 videos from 40 volunteers (across nine anatomical regions) without using the device. The artificial-intelligence colour overlay was subsequently applied. Three more experts independently reviewed each video (with the original unmodified video) to assess accuracy of the colour overlay in relation to key anatomical structures (true positive/negative and false positive/negative) and the potential for highlighting to modify perceived risk of adverse events (needle trauma to nerves, arteries, pleura, and peritoneum) or block failure.

RESULTS

The artificial-intelligence models identified the structure of interest in 93.5% of cases (1519/1624), with a false-negative rate of 3.0% (48/1624) and a false-positive rate of 3.5% (57/1624). Highlighting was judged to reduce the risk of unwanted needle trauma to nerves, arteries, pleura, and peritoneum in 62.9-86.4% of cases (302/480 to 345/400), and to increase the risk in 0.0-1.7% (0/160 to 8/480). Risk of block failure was reported to be reduced in 81.3% of scans (585/720) and to be increased in 1.8% (13/720).

CONCLUSIONS

Artificial intelligence-based devices can potentially aid image acquisition and interpretation in ultrasound-guided regional anaesthesia. Further studies are necessary to demonstrate their effectiveness in supporting training and clinical practice.

CLINICAL TRIAL REGISTRATION

NCT04906018.

Recommendations for anatomical structures to identify on ultrasound for the performance of intermediate and advanced blocks in ultrasound-guided regional anesthesia

Recent recommendations describe a set of core anatomical structures to identify on ultrasound for the performance of basic blocks in ultrasound-guided regional anesthesia (UGRA). This project aimed to generate consensus recommendations for core structures to identify during the performance of intermediate and advanced blocks. An initial longlist of structures was refined by an international panel of key opinion leaders in UGRA over a three-round Delphi process. All rounds were conducted virtually and anonymously. Blocks were considered twice in each round: for “orientation scanning” (the dynamic process of acquiring the final view) and for “block view” (which visualizes the block site and is maintained for needle insertion/injection). A “strong recommendation” was made if ≥75% of participants rated any structure as “definitely include” in any round. A “weak recommendation” was made if >50% of participants rated it as “definitely include” or “probably include” for all rounds, but the criterion for strong recommendation was never met. Structures which did not meet either criterion were excluded. Forty-one participants were invited and 40 accepted; 38 completed all three rounds. Participants considered the ultrasound scanning for 19 peripheral nerve blocks across all three rounds. Two hundred and seventy-four structures were reviewed for both orientation scanning and block view; a “strong recommendation” was made for 60 structures on orientation scanning and 44 on the block view. A “weak recommendation” was made for 107 and 62 structures, respectively. These recommendations are intended to help standardize teaching and research in UGRA and support widespread and consistent practice.

Core outcome set for peripheral regional anesthesia research: a systematic review and Delphi study

BACKGROUND/IMPORTANCE

There is heterogeneity among the outcomes used in regional anesthesia research.

OBJECTIVE

We aimed to produce a core outcome set for regional anesthesia research.

METHODS

We conducted a systematic review and Delphi study to develop this core outcome set. A systematic review of the literature from January 2015 to December 2019 was undertaken to generate a long list of potential outcomes to be included in the core outcome set. For each outcome found, the parameters such as the measurement scale, timing and definitions, were compiled. Regional anesthesia experts were then recruited to participate in a three-round electronic modified Delphi process with incremental thresholds to generate a core outcome set. Once the core outcomes were decided, a final Delphi survey and video conference vote was used to reach a consensus on the outcome parameters.

RESULTS

Two hundred and six papers were generated following the systematic review, producing a long list of 224 unique outcomes. Twenty-one international regional anesthesia experts participated in the study. Ten core outcomes were selected after three Delphi survey rounds with 13 outcome parameters reaching consensus after a final Delphi survey and video conference.

CONCLUSIONS

We present the first core outcome set for regional anesthesia derived by international expert consensus. These are proposed not to limit the outcomes examined in future studies, but rather to serve as a minimum core set. If adopted, this may increase the relevance of outcomes being studied, reduce selective reporting bias and increase the availability and suitability of data for meta-analysis in this area.

Recommendations for effective documentation in regional anesthesia: an expert panel Delphi consensus project

Background and objectives

Documentation is important for quality improvement, education, and research. There is currently a lack of recommendations regarding key aspects of documentation in regional anesthesia. The aim of this study was to establish recommendations for documentation in regional anesthesia.

Methods

Following the formation of the executive committee and a directed literature review, a long list of potential documentation components was created. A modified Delphi process was then employed to achieve consensus amongst a group of international experts in regional anesthesia. This consisted of 2 rounds of anonymous electronic voting and a final virtual round table discussion with live polling on items not yet excluded or accepted from previous rounds. Progression or exclusion of potential components through the rounds was based on the achievement of strong consensus. Strong consensus was defined as ≥75% agreement and weak consensus as 50%–74% agreement.

Results

Seventy-seven collaborators participated in both rounds 1 and 2, while 50 collaborators took part in round 3. In total, experts voted on 83 items and achieved a strong consensus on 51 items, weak consensus on 3 and rejected 29.

Conclusion

By means of a modified Delphi process, we have established expert consensus on documentation in regional anesthesia.

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.

Supplementary Information

The online version contains supplementary material available at 10.1007/s12630-021-02150-8.

International consensus on anatomical structures to identify on ultrasound for the performance of basic blocks in ultrasound-guided regional anesthesia

There is no universally agreed set of anatomical structures that must be identified on ultrasound for the performance of ultrasound-guided regional anesthesia (UGRA) techniques. This study aimed to produce standardized recommendations for core (minimum) structures to identify during seven basic blocks. An international consensus was sought through a modified Delphi process. A long-list of anatomical structures was refined through serial review by key opinion leaders in UGRA. All rounds were conducted remotely and anonymously to facilitate equal contribution of each participant. Blocks were considered twice in each round: for "orientation scanning" (the dynamic process of acquiring the final view) and for the "block view" (which visualizes the block site and is maintained for needle insertion/injection). Strong recommendations for inclusion were made if ≥75% of participants rated a structure as "definitely include" in any round. Weak recommendations were made if >50% of participants rated a structure as "definitely include" or "probably include" for all rounds (but the criterion for "strong recommendation" was never met). Thirty-six participants (94.7%) completed all rounds. 128 structures were reviewed; a "strong recommendation" is made for 35 structures on orientation scanning and 28 for the block view. A "weak recommendation" is made for 36 and 20 structures, respectively. This study provides recommendations on the core (minimum) set of anatomical structures to identify during ultrasound scanning for seven basic blocks in UGRA. They are intended to support consistent practice, empower non-experts using basic UGRA techniques, and standardize teaching and research.

Non-Fellowship regional anesthesia training and assessment: an international Delphi study on a consensus curriculum

BACKGROUND AND OBJECTIVES

While there are several published recommendations and guidelines for trainees undertaking subspecialty Fellowships in regional anesthesia, a similar document describing a core regional anesthesia curriculum for non-fellowship trainees is less well defined. We aimed to produce an international consensus for the training and teaching of regional anesthesia that is applicable for the majority of worldwide anesthesiologists.

METHODS

This anonymous, electronic Delphi study was conducted over two rounds and distributed to current and immediate past (within 5 years) directors of regional anesthesia training worldwide. The steering committee formulated an initial list of items covering nerve block techniques, learning objectives and skills assessment and volume of practice, relevant to a non-fellowship regional anesthesia curriculum. Participants scored these items in order of importance using a 10-point Likert scale, with free-text feedback. Strong consensus items were defined as highest importance (score ≥8) by ≥70% of all participants.

RESULTS

469 participants/586 invitations (80.0% response) scored in round 1, and 402/469 participants (85.7% response) scored in round 2. Participants represented 66 countries. Strong consensus was reached for 8 core peripheral and neuraxial blocks and 17 items describing learning objectives and skills assessment. Volume of practice for peripheral blocks was uniformly 16-20 blocks per anatomical region, while ≥50 neuraxial blocks were considered minimum.

CONCLUSIONS

This international consensus study provides specific information for designing a non-fellowship regional anesthesia curriculum. Implementation of a standardized curriculum has benefits for patient care through improving quality of training and quality of nerve blocks.

Standardizing nomenclature in regional anesthesia: an ASRA-ESRA Delphi consensus study of abdominal wall, paraspinal, and chest wall blocks

BACKGROUND

There is heterogeneity in the names and anatomical descriptions of regional anesthetic techniques. This may have adverse consequences on education, research, and implementation into clinical practice. We aimed to produce standardized nomenclature for abdominal wall, paraspinal, and chest wall regional anesthetic techniques.

METHODS

We conducted an international consensus study involving experts using a three-round Delphi method to produce a list of names and corresponding descriptions of anatomical targets. After long-list formulation by a Steering Committee, the first and second rounds involved anonymous electronic voting and commenting, with the third round involving a virtual round table discussion aiming to achieve consensus on items that had yet to achieve it. Novel names were presented where required for anatomical clarity and harmonization. Strong consensus was defined as ≥75% agreement and weak consensus as 50% to 74% agreement.

RESULTS

Sixty expert Collaborators participated in this study. After three rounds and clarification, harmonization, and introduction of novel nomenclature, strong consensus was achieved for the names of 16 block names and weak consensus for four names. For anatomical descriptions, strong consensus was achieved for 19 blocks and weak consensus was achieved for one approach. Several areas requiring further research were identified.

CONCLUSIONS

Harmonization and standardization of nomenclature may improve education, research, and ultimately patient care. We present the first international consensus on nomenclature and anatomical descriptions of blocks of the abdominal wall, chest wall, and paraspinal blocks. We recommend using the consensus results in academic and clinical practice.

Ergonomics in the anaesthetic workplace: Guideline from the Association of Anaesthetists

Ergonomics in relation to anaesthesia is the scientific study of the interaction between anaesthetists and their workspace environment in order to promote safety, performance and well-being. The foundation for avoiding pain or discomfort at work is to adopt and maintain a good posture, whether sitting or standing. Anaesthetists should aim to keep their posture as natural and neutral as possible. The successful practice of anaesthesia relies on optimisation of ergonomics and lack of attention to detail in this area is associated with impaired performance. The anaesthetic team should wear comfortable clothing, including appropriately-sized personal protective equipment where necessary. Temperature, humidity and light should be adequate at all times. The team should comply with infection prevention and control guidelines and monitoring as recommended by the Association of Anaesthetists. Any equipment or machinery that is mobile should be positioned where it is easy to view or reach without having to change the body or head position significantly when interacting with it. Patients who are supine should, whenever possible, be raised upwards to limit the need to lean towards them. Any item required during a procedure should be positioned on trays or trolleys that are close to the dominant hand. Pregnancy affects the requirements for standing, manually handling, applying force when operating equipment or moving machines and the period over which the individual might have to work without a break. Employers have a duty to make reasonable adjustments to accommodate disability in the workplace. Any member of staff with a physical impairment needs to be accommodated and this includes making provision for a wheelchair user who needs to enter the operating theatre and perform their work.

Recommendations for standards of monitoring during anaesthesia and recovery 2021: Guideline from the Association of Anaesthetists

This guideline updates and replaces the 5th edition of the Standards of Monitoring published in 2015. The aim of this document is to provide guidance on the minimum standards for monitoring of any patient undergoing anaesthesia or sedation under the care of an anaesthetist. The recommendations are primarily aimed at anaesthetists practising in the UK and Ireland, but it is recognised that these guidelines may also be of use in other areas of the world. Minimum standards for monitoring patients during anaesthesia and in the recovery phase are included. There is also guidance on monitoring patients undergoing sedation and during transfer. There are new sections specifically discussing capnography, sedation and regional anaesthesia. In addition, the indications for processed electroencephalogram and neuromuscular monitoring have been updated.

Mode of Anesthesia and Quality of Recovery After Breast Surgery: A Case Series of 100 Patients

PURPOSE

Regional anesthesia techniques may improve patient recovery beyond treating postoperative pain alone and may facilitate patients in their return to functional, psychological as well as emotional baselines. We hypothesized that the quality of recovery (QoR) experienced by patients following breast surgery was associated with the type of anesthesia received as well as the use of a regional anesthesia technique during surgery.

METHODS

We performed a single-center prospective, observational cohort study of patients undergoing elective breast procedures (both cancer and non-cancer surgery).

RESULTS

 One hundred patients completed baseline QoR-15 questionnaires prior to surgery, of which 96 also completed QoR-15 questionnaires on postoperative day 1. The median (IQR) QoR-15 score at baseline was 133 (124-141), decreasing to 121 (106.75-136.25) on postoperative day 1. In multivariable linear regression analysis, paravertebral blocks (PVB) were associated with a 16.7 point higher overall QoR-15 score on postoperative day 1 compared to no block (95% Confidence Interval [CI]: 7.7-25.8, p<0.001); while the use of combination blocks was associated with a 21.8 point higher postoperative QoR-15 score compared to no block (95% CI: 12.8-30.8, p<0.001). PVB and combination blocks were further associated with better postoperative pain, physical comfort, physical independence and emotional state scores, compared with no block. The use of total intravenous anesthetic was not associated with differences in postoperative QoR-15 score versus volatile anesthetic, after covariate adjustment.

CONCLUSION

Breast surgery patients receiving PVB or a combination of regional blocks during surgery have higher postoperative QoR-15 scores, after adjustment for other factors.

Ultrasound-guided fascial plane blocks of the chest wall: a state-of-the-art review

Ultrasound-guided fascial plane blocks of the chest wall are increasingly popular alternatives to established techniques such as thoracic epidural or paravertebral blockade, as they are simple to perform and have an appealing safety profile. Many different techniques have been described, which can be broadly categorised into anteromedial, anterolateral and posterior chest wall blocks. Understanding the relevant clinical anatomy is critical not only for block performance, but also to match block techniques appropriately with surgical procedures. The sensory innervation of tissues deep to the skin (e.g. muscles, ligaments and bone) can be overlooked, but is often a significant source of pain. The primary mechanism of action for these blocks is a conduction blockade of sensory afferents travelling in the targeted fascial planes, as well as of peripheral nociceptors in the surrounding tissues. A systemic action of absorbed local anaesthetic is plausible but unlikely to be a major contributor. The current evidence for their clinical applications indicates that certain chest wall techniques provide significant benefit in breast and thoracic surgery, similar to that provided by thoracic paravertebral blockade. Their role in trauma and cardiac surgery is evolving and holds great potential. Further avenues of research into these versatile techniques include: optimal local anaesthetic dosing strategies; high-quality randomised controlled trials focusing on patient-centred outcomes beyond acute pain; and comparative studies to determine which of the myriad blocks currently on offer should be core competencies in anaesthetic practice.

Impact of parallel processing of regional anesthesia with block rooms on resource utilization and clinical outcomes: a systematic review and meta-analysis

Block rooms allow parallel processing of surgical patients with the purported benefits of improving resource utilization and patient outcomes. There is disparity in the literature supporting these suppositions. We aimed to synthesize the evidence base for parallel processing by conducting a systematic review and meta-analysis. A systematic search was undertaken of Medline, Embase, Web of Science, Cumulative Index to Nursing and Allied Health Literature (CINAHL), the National Health Service (NHS) National Institute for Health Research Centre for Reviews and Dissemination database, and Google Scholar for terms relating to regional anesthesia and block rooms. The primary outcome was anesthesia-controlled time (ACT; time from entry of the patient into the operating room (OR) until the start of surgical prep plus surgical closure to exit of patient from the OR). Secondary outcomes of interest included other resource-utilization parameters such as turnover time (TOT; time between the exit of one patient from the OR and the entry of another), time spent in the postanesthesia care unit (PACU), OR throughput, and clinical outcomes such as pain scores, nausea and vomiting, and patient satisfaction. Fifteen studies were included involving 8888 patients, of which 3364 received care using a parallel processing model. Parallel processing reduced ACT by a mean difference (95% CI) of 10.4 min (16.3 to 4.5; p<0.0001), TOT by 16.1 min (27.4 to 4.8; p<0.0001) and PACU stay by 26.6 min (47.1 to 6.1; p=0.01) when compared with serial processing. Moreover, parallel processing increased daily OR throughout by 1.7 cases per day (p<0.0001). Clinical outcomes all favored parallel processing models. All studies showed moderate-to-critical levels of bias. Parallel processing in regional anesthesia appears to reduce the ACT, TOT, PACU time and improved OR throughput when compared with serial processing. PROSPERO CRD42018085184.

A Cohort Study of Emergency Surgery Caseload and Regional Anesthesia Provision at a Tertiary UK Hospital During the Initial COVID-19 Pandemic

Study objective 

Analysis of emergency cases performed during initial coronavirus disease 2019 (COVID-19) pandemic and the proportion completed under regional anesthesia (RA).

Design

Cohort study comparing surgical caseload during initial seven-week COVID-19 pandemic in 2020. Comparison was made with pre-COVID-19 caseload over the corresponding seven-week timeframe in 2019.

Setting

The setting of the study was emergency surgery theaters at Guy’s and St Thomas’ NHS Foundation Trust, London, UK.

Patients

All patients requiring emergency surgery over the defined study period were reviewed with the exception of obstetric and pediatric populations.

Interventions

Surgical caseload for 2020 and 2019 cohorts established using the Galaxy IT system used to log all operations. All relevant anesthetic charts for the 2020 cohort were subsequently reviewed to ascertain perioperative use of RA.

Measurements

The type of block, mode of approach, experience of the operator, personal protective equipment (PPE) worn, block complications, type of sedation and complications were entered into database.

Main results

A total of 338 emergency surgical cases were performed during the COVID-19 pandemic in 2020, compared to 603 cases over the corresponding period in 2019. This showed a 44% decrease in emergency surgical workload. There was a marked disparity in reduction of surgical caseload by surgical subspecialty. Trauma (137 vs 66 cases), a 52% decrease, and general surgery (193 vs 64 cases), a 66% decrease, were the most pronounced, and explanations for this are explored. RA was performed in 34% (26% as primary technique) of cases during the COVID-19 pandemic. The use of RA as the primary anesthesia technique was noticeably higher than previous UK data (11%), and was prominent in specialties such as general surgery, gynecology and urology, not traditionally completed under RA.

Conclusions

Surgical RA (and general anesthesia avoidance) has a significant role in the future to ensure high-quality perioperative care for patients whilst minimizing exposure to staff and utilization of scarce resources (PPE).

Analgesic benefits and clinical role of the posterior suprascapular nerve block in shoulder surgery: a systematic review, meta-analysis and trial sequential analysis

The posterior suprascapular nerve block has been proposed as an analgesic alternative for shoulder surgery based on the publication of several comparisons with interscalene block that failed to detect differences in analgesic outcomes. However, quantification of the absolute treatment effect of suprascapular nerve block on its own, in comparison with no block (control), to corroborate the aforementioned conclusions has been lacking. This study examines the absolute analgesic efficacy of suprascapular nerve block compared with control for shoulder surgery. We systematically sought electronic databases for studies comparing suprascapular nerve block with control. The primary outcomes included postoperative 24-h cumulative oral morphine consumption and the difference in area under the curve for 24-h pooled pain scores. Secondary outcomes included the incidence of opioid-related side-effects (postoperative nausea and vomiting) and patient satisfaction. Data were pooled using random-effects modelling. Ten studies (700 patients) were analysed; all studies examined landmark-guided posterior suprascapular nerve block performed in the suprascapular fossa. Suprascapular nerve block was statistically but not clinically superior to control for postoperative 24-h cumulative oral morphine consumption, with a weighted mean difference (99%CI) of 11.41 mg (-21.28 to -1.54; p = 0.003). Suprascapular nerve block was also statistically but not clinically superior to control for area under the curve of pain scores, with a mean difference of 1.01 cm.h. Nonetheless, suprascapular nerve block reduced the odds of postoperative nausea and vomiting and improved patient satisfaction. This review suggests that the landmark-guided posterior suprascapular nerve block does not provide clinically important analgesic benefits for shoulder surgery. Investigation of other interscalene block alternatives is warranted.

Retroclavicular vs supraclavicular brachial plexus block for distal upper limb surgery: a randomised, controlled, single-blinded trial

BACKGROUND

Regional anaesthesia for upper limb surgery is routinely performed with brachial plexus blocks. A retroclavicular brachial plexus block has recently been described, but has not been adequately compared with another approach. This randomised controlled single-blinded trial tested the hypothesis that the retroclavicular approach, when compared with the supraclavicular approach, would increase the success rate.

METHODS

One hundred and twenty ASA physical status 1-3 patients undergoing distal upper limb surgery were randomised to receive an ultrasound-guided retroclavicular or supraclavicular brachial plexus block with 30 mL of a 1:1 mixture of mepivacaine 1% and ropivacaine 0.5%, using a single-injection technique without needle tip repositioning. The primary outcome was block success rate 30 min after local anaesthetic injection, defined as a composite score of 14 of 16 points, inclusive of sensory and motor components. Secondary outcomes included needling time, time to first opioid request, oxycodone consumption, and pain scores (numeric rating scale, 0-10) at 24 h postoperatively.

RESULTS

Success rates were 98.3% [95% confidence interval (CI): 90.8%, 99.9%] and 98.3% [95% CI: 90.9%, 99.9%] in the supraclavicular and retroclavicular groups, respectively (P=0.99). The mean needling time was reduced in the supraclavicular group [supraclavicular: 5.0 (95% CI: 4.7, 5.4) min; retroclavicular: 6.0 (95% CI: 5.4, 6.6) min; P=0.006]. The mean time to first opioid request was similar between groups [supraclavicular: 439 (95% CI: 399, 479) min; retroclavicular: 447 (95% CI: 397, 498) min; P=0.19] as were oxycodone consumption [supraclavicular: 10.0 (95% CI: 6.5, 13.5 mg; retroclavicular: 7.9 (95% CI: 4.8, 11.0) mg; P=0.80] and pain scores at 24 h postoperatively [supraclavicular: 1.2 (95% CI: 2.1, 2.7); retroclavicular: 1.5 (95% CI: 1.6, 2.4); P=0.09].

CONCLUSIONS

Ultrasound-guided retroclavicular and supraclavicular brachial plexus blocks share identical success rates, while providing similar pain relief. Reduced needling time in the supraclavicular approach is not clinically relevant.

CLINICAL TRIAL REGISTRATION

NCT02641613.

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.

Intraoperative Assessment of Tumor Resection Margins in Breast-Conserving Surgery Using 18F-FDG Cerenkov Luminescence Imaging: A First-in-Human Feasibility Study

In early-stage breast cancer, the primary treatment option for most women is breast-conserving surgery (BCS). There is a clear need for more accurate techniques to assess resection margins intraoperatively, because on average 20% of patients require further surgery to achieve clear margins. Cerenkov luminescence imaging (CLI) combines optical and molecular imaging by detecting light emitted by 18F-FDG. Its high-resolution and small size imaging equipment make CLI a promising technology for intraoperative margin assessment. A first-in-human study was conducted to evaluate the feasibility of 18F-FDG CLI for intraoperative assessment of tumor margins in BCS. Methods: Twenty-two patients with invasive breast cancer received 18F-FDG (5 MBq/kg) 45-60 min before surgery. Sentinel lymph node biopsy was performed using an increased 99mTc-nanocolloid activity of 150 MBq to facilitate nodal detection against the γ-probe background signal (cross-talk) from 18F-FDG. The cross-talk and 99mTc dose required was evaluated in 2 lead-in studies. Immediately after excision, specimens were imaged intraoperatively in an investigational CLI system. The first 10 patients were used to optimize the imaging protocol; the remaining 12 patients were included in the analysis dataset. Cerenkov luminescence images from incised BCS specimens were analyzed postoperatively by 2 surgeons blinded to the histopathology results, and mean radiance and margin distance were measured. The agreement between margin distance on CLI and histopathology was assessed. Radiation doses to staff were measured. Results: Ten of the 12 patients had an elevated tumor radiance on CLI. Mean radiance and tumor-to-background ratio were 560 ± 160 photons/s/cm2/sr and 2.41 ± 0.54, respectively. All 15 assessable margins were clear on CLI and histopathology. The agreement in margin distance and interrater agreement was good (κ = 0.81 and 0.912, respectively). Sentinel lymph nodes were successfully detected in all patients. The radiation dose to staff was low; surgeons received a mean dose of 34 ± 15 μSv per procedure. Conclusion: Intraoperative 18F-FDG CLI is a promising, low-risk technique for intraoperative assessment of tumor margins in BCS. A randomized controlled trial will evaluate the impact of this technique on reexcision rates.