Peripheral regional anesthesia (RA) is increasingly popular for various surgical procedures, offering benefits such as reduced pain and faster recovery. However, ensuring safety and quality in RA requires adherence to best practices and addressing potential risks. This article provides a comprehensive overview of current recommendations and controversies surrounding the quality and safety of RA.
Preoperative Preparation
Patient education is crucial for managing expectations and improving satisfaction. Providing clear information about the procedure, what to expect, and post-operative care can help alleviate anxiety. Medication management is also essential, with a focus on separating perineural from intravenous drugs and labeling syringes to reduce errors.
Intraoperative Practices
Dual guidance using peripheral nerve stimulation and ultrasound can minimize the risk of intraneural needle tip placement. Sedation techniques, such as using benzodiazepines or low-dose propofol, can provide anxiolysis. Audiovisual distraction techniques, like music or virtual reality headsets, can be equally effective and free from adverse effects.
Postoperative Care
Continuous monitoring until the block is tested and proven effective is essential. Discharge advice should include measures to protect the insensate limb from harm and appropriate analgesic use to avoid rebound pain.
Preventing Wrong-Sided Nerve Block
Wrong-sided nerve block (WSNB) is a rare but significant adverse event. Implementing a 'stop' moment to confirm the site immediately before needle insertion can reduce the risk of WSNB. Encouraging a culture where all personnel feel empowered to speak up if they see a potential WSNB is also important.
Infection Prevention
Using sterile, single-use transducer covers and disinfecting the transducer and cable between patients can minimize infection risks. Sterile gel should be used as a conductive medium, and needling through the gel should be avoided.
Nerve Injury Mitigation
Performing blocks on awake patients, using short-bevel needles, and employing a tangential approach can reduce the risk of nerve injury. Dual guidance with peripheral nerve stimulation can help detect too-close needle/nerve placement.
Systemic Toxicity Prevention
Administering local anesthetics at the lowest effective concentration and volume, using slow, fractionated injections, and frequent aspiration can prevent systemic toxicity. Understanding the mechanisms of toxicity, risk factors, and safe doses of local anesthetics is essential for safe practice.
Image Optimization
Ultrasound guidance is now the dominant method of nerve location, allowing for better visualization of the needle and nerve, improving block success, and reducing complications. Strategies to address common technical challenges include adjusting the ultrasound machine settings, optimizing the probe/needle alignment, and using echogenic needles.
This chart takes a quick look at the challenges and suggestions for improvements.
Challenge | Presentation/problem | Improvement strategies |
US machine | ||
Axial resolution | Poor differentiation of discrete structures at different depths | Choose higher frequency for superficial structures and lower for deep structures, adjust gain, adjust time gain compensation (TGC) |
Lateral resolution | Poor differentiation discrete structures at same depth | Adjust focal point to level of target, high frequency probe |
Operator-related | ||
Anisotropy – suboptimal image caused by probe angulation | Tilt probe until perpendicular to nerve | |
Probe/skin interface signal dropout | Careful ultrasound transmission gel/probe cover application | |
Artefacts | ||
Acoustic shadowing | Deeper tissue appears less echogenic, e.g. behind air or bone | Change transducer position |
Acoustic enhancement | Tissue, below the vessel/cyst, appears brighter and can be confused for a nerve | Change angle/plane, dynamic scanning/tracking, PNS, compression of a vessel |
Miscellaneous artefacts | Tissue reverberation artefacts – e.g. double-barrelled subclavian artery (duplication of artery image with artefact deep to actual artery) | Recognition, increase probe/skin pressure, adjust scanning angle, anatomical knowledge |
Air bubbles – hyperechoic artefact after injection | Avoid air in syringe/needle, adjust probe position | |
Anatomical structures resembling nerve | VesselsTendonLymph nodesAnatomical variation | Color Doppler, compressibility, pulsatileFibrillar pattern, dynamic scanning/tracking, PNSDynamic scanning/tracking, PNSKnowledge of common variations |
Block needle | ||
Artefacts | Reverberation artefact | Needle is perpendicular to beam – increase angulation, decrease frequency |
Mirror artefact | Recognition, change scanning direction | |
Bayonet artefact – bent needle tip image | Recognition | |
Patient | ||
Speckling (granular structure) and clutter (diffuse haze) covering deeper located nerves | Processing filters | |
Attenuation – reduced tissue penetration with increased depth | Use lower frequency transducer, increase gain, adjust TGC, increase probe pressure to reduce depth | |
Poor needle visualization | Select needle entry point to reduce angulation | |
Oedema | Decreased echo contrast, displaced anatomy | Use different site |
Technological Advances
Recent advancements in needle tip identification technologies and needle guide devices have improved the accuracy and safety of RA procedures. However, more research is needed to establish their efficacy.
Organizational Changes for Quality and Safety
Simple organizational changes, such as optimizing operating list order and using a parallel processing model, can improve patient flow and reduce anesthetic time. The block room model concentrates training opportunities and allows more time for teaching, improving skill development and retention.
Skill Development and Retention
One of the most important aspects of RA success is skill development and retention. The block room model not only improves patient flow but also provides concentrated training opportunities. Historically, training in RA has been assessed on a quantitative basis alone and limited by case exposure. Clinical exposure remains important as it has been linked to the avoidance of complications. However, more recent emphasis has been placed on both the quality of training provided and the assessment of competence, rather than solely on the number of blocks performed. Simulation has been shown to increase the proficiency of new trainees acquiring skills in ultrasound-guided RA. Achieving and maintaining competence is a challenge, and initially restricting practice to a small range of high-value basic ultrasound-guided blocks probably represents the best way to develop competence for the majority of anesthetists.
Further Studies Required
More research is needed to understand the long-term outcomes of patients undergoing RA. Establishing national and international clinical registries to track patient outcomes and complications can provide valuable data for improving RA practices. Studies on the efficacy of new needle tip identification technologies and needle guide devices can further enhance RA safety.
For a complete listing of factors contributing to a wrong-sided peripheral nerve blocks and strategies and methods to reduce nerve injury refer to the full article here.
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To deliver the most effective training products and courses, Valkyrie meticulously reviews past and current articles and conducts expert interviews. This approach helps us understand current challenges and future considerations in teaching and learning, including skills development. We selected this article to highlight both past and present challenges and the advancements, like Valkyrie simulators that have led to improved success.
Reference:
Best practices for safety and quality in peripheral regional anaesthesia
Topor, B. et al.
BJA Education, Volume 20, Issue 10, 341 - 347
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