Ultrasound-guided Regional Anesthesia Research Articles

Bilateral ultrasound-guided maxillary and mandibular combined nerves block reduces morphine consumption after double-jaw orthognathic surgery: a randomized controlled trial

BackgroundDouble-jaw surgeries are known to be painful and to require opioids. Maxillary (V2) and mandibular (V3) nerves block could provide adequate pain management with minimal opioid-related side effects. Our main...

Integrative Artificial Intelligence in Regional Anesthesia: Enhancing Precision, Efficiency, Outcomes and Limitations

Artificial intelligence (AI) has made remarkable progress in various domains, outperforming human capabilities in many areas. It is no surprise that AI is being increasingly used in healthcare practices, including regional anesthesia. Recent advancements in AI have enabled its integration into the field of regional anesthesia, promising to enhance precision, efficiency, and patient outcomes. By utilizing machine learning algorithms and predictive analytics, AI has the potential to revolutionize the way regional anesthesia procedures are conducted and managed. Ultrasound-guided regional anesthesia (UGRA) significantly enhances the success rates of regional blocks while mitigating complication risks. This review scrutinizes the burgeoning role of artificial intelligence (AI) in UGRA, detailing its evolution and pivotal function in optimizing sonographic imaging, target delineation, needle guidance, and local anesthetic administration. AI's support is invaluable, particularly for non-experts in training and clinical practice and for experts in educational settings. By systematically analyzing the capabilities and applications of AI in regional anesthesia, we assess its contribution to procedural precision, safety, and educational advancement. The findings reveal that AI-assisted UGRA not only bolsters the accuracy of anatomical identification, thus improving patient safety, but also standardizes the quality of care across varying expertise levels. The integration of AI into UGRA emerges as a transformative influence in anesthesiology, promising to reshape the domain with enhanced precision, efficiency, and patient-centered care.

The Forces Associated with Bolus Injection and Continuous Infusion Techniques during Ultrasound-Targeted Nerve Contact: An Ex Vivo Study

Ultrasound-guided regional anaesthesia with real-time visualization of anatomical structures and needle trajectory has become the standard method for accurately achieving nerve block procedures. Nevertheless, ultrasound is particularly limited in accurately detecting the needle tip in tissues with complex echogenicity. Fat-filled circumneural fascial tissue provides a barrier to local anaesthetic diffusion. Injection during gentle needle nerve contact is more likely to spread under the circumneurium (halo sign). On the other hand, excessive force may cause hematoma or activate the piezo ion channels and intraneural calcium release. Therefore, it is vital to understand the mechanics of needle–tissue interaction for optimizing the procedural outcomes and patients’ safety. We hypothesised that continuous fluid infusion would reduce the needle force applied on the nerve compared to that of bolus injection. Thus, the primary objective of this study was to compare the forces associated with the bolus injection and continuous infusion techniques on the sciatic nerves of fresh lamb legs ex vivo. A needle combining pressure and force was inserted into six legs of lambs ex vivo using a motor stage at a constant velocity and imaged with a linear transducer. Saline injections were block randomised to bolus injection or infusion in the muscle upon gently touching and indenting of the epineurium at nine sites on six sciatic nerves at three angles (30°, 45° and 60°) in each location. The bolus was delivered over 6 s and infused for over 60 s. The result showed less force was generated during the infusion technique when gently touching the epineurium than that of the bolus technique, with p = 0.004, with significant differences observed at a 60° angle (0.49 N, p = 0.001). The injection pressure was also lower when light epineurium touches were applied (9.6 kPa, p = 0.02) and at 60° (8.9 kPa). The time to peak pressure varied across the insertion angles (p < 0.001), with the shortest time at 60° (6.53 s). This study explores future applications by emphasizing the significance of understanding needle–tissue interaction mechanics. This understanding is crucial for optimizing the procedural outcomes and enhancing patients’ safety in ultrasound-guided regional anaesthesia administration. Specifically, continuous infusion demonstrated a notable reduction in needle force compared to that of the bolus injection, especially during gentle epineurium contact.

Comparison of diffusion ranges at different local anesthetic volumes during superior laryngeal nerve block

ObjectivesUltrasound-guided superior laryngeal nerve (SLN) block is a practical and painless approach to avoid the hemodynamic stress response during endotracheal intubation and relieve sore throat after laryngeal surgery. The main purpose of this study was to establish an optimal dosage of local anesthetic when performing SLN block to help anesthetists balance analgesia and side effects.MethodsTwenty fresh larynx specimens were obtained immediately after resection and then injected with 2-, 3-, 4-, or 5- mL of a lidocaine-blue dye mixture at bilateral SLN puncture sites. Superficial areas of deposited blue dye were measured. Dye leakage and surrounding dyed tissue were recorded. Another 40 patients were included in the ultrasound investigation. Distances between the internal branch of the SLN (iSLN) and adjacent structures were calculated.ResultsThe dye spread area was greater with the administration of larger doses, especially to the visceral space. A 2- or 3-mL injection of local anesthetic was sufficient to infiltrate the SLN gap. A higher incidence of dye leaking out of the thyrohyoid membrane and anterior epiglottis space was observed; furthermore, there was substantially more dyed hyoid/thyroid cartilage with 4 and 5 mL of injected dye mixture than 2 mL. There was no significant difference between the specimen and ultrasound measurements of for length of iSLN-adjacent structures.ConclusionsIn the Chinese population, 2- or 3- mL of local anesthetic is a safe dose during SLN block. A larger volume could overflow from the cavity to cause complications. The thyrohyoid membrane combined with the superior laryngeal artery is a reliable target for positioning the iSLN during ultrasound-guided regional anesthesia.

No evidence of fascicular injury following a low-volume intraneural injection of the median nerve: a cadaveric study

BackgroundThe test dose or hydrolocation technique allows rapid detection of spread location. Though its primary aim is to enhance safety in peripheral nerve blocks, evidence on the potential risks of...

A Nerve Block Team in the Emergency Department

Objectives To improve pain management in the emergency department (ED), emergency physicians are performing an increasing number of ultrasound-guided regional anesthesia procedures (nerve blocks). We aimed to examine the effect of a dedicated emergency department (ED) nerve block team (NBT) on the number and types of ultrasound-guided nerve blocks administered in the ED. Methods We performed a retrospective chart review comparing the nine-month period before and after the creation of a dedicated NBT. This was performed at a tertiary care urban hospital that is a level 1 trauma center. We assessed and compared the number and types of nerve blocks performed, level of learners who performed nerve blocks, and time of ED arrival to disposition, before and after implementation of the NBT. Results The utilization of nerve blocks rose from 79 prior to the establishment of the NBT to 108 following its creation, representing a 36.7% increase. The average duration of stay in the emergency department decreased by 51 minutes, though this change did not demonstrate statistical significance (P=0.1237). There was an increased variety in the types of nerve blocks performed. Conclusion The introduction of a NBT led to a rise in both the quantity and diversity of nerve blocks conducted in the ED.

Building Affordable, Durable, Medium-fidelity Ballistic Gel Phantoms for Ultrasound-guided Nerve Block Training.

Ultrasound phantoms - alternatives to live human tissue - give learners the opportunity to practice ultrasound-guided regional anesthesia without introducing undue risk to patients. Gelatin-based phantoms provide educators with durable and reusable task trainers; however, commercially available gel-based phantoms are expensive. Here, we investigate the production of durable, low-cost, ballistic gel-based ultrasound phantoms for median, femoral, suprainguinal fascia iliaca plane, and serratus anterior plane nerve blocks, as well as a methodology for producing a phantom for any ultrasound-guided nerve block procedure. Computer-aided design (CAD) software was utilized to design four phantoms replicating the anatomy of median, femoral, suprainguinal fascia iliaca plane, and serratus anterior plane nerve blocks, including relevant landmarks and tissue planes. Plastic models of the desired tissue planes were 3D printed and used to create silicone molds. Ballistic gel was melted and mixed with flour and dye to create a liquid, echogenic ballistic gel, which was poured into the silicone molds. Vessels were simulated by creating negative space in the ballistic gel using metal rods. Nerves were simulated using yarn submerged in ultrasound gel. Simulated bones were designed using CAD and 3D printed. Ballistic gel is a versatile, durable medium that can be used to simulate a variety of tissues and can be melted and molded into any shape. Under ultrasound, these phantoms provide realistic tissue planes that represent the borders between different layers of skin, muscle, and fascia. The echogenicity of the muscle tissue layers, nerves, vessels, and bones is realistic, and bones have significant posterior shadowing as would be observed in a human subject. These phantoms cost $200 each for the first phantom and $60 for each subsequent phantom. These phantoms require some technical skill to design, but they can be built for just 4% of the cost of their commercial counterparts.

Ultrasound-Guided Pediatric Regional Anesthesia for Orthopedic Surgery

Ultrasound-Guided Pediatric Regional Anesthesia for Orthopedic Surgery

Spinal Anestezi Altında Sezaryen Doğumda Postoperatif Analjezi için Transversalis Fasya Plan Bloğunun Transversus Abdominis Plan Bloğuyla Karşılaştırılması: Retrospektif Bir Çalışma

Objective: Transversalis fascia plane (TFP) and transversus abdominis plane (TAP) blocks are used for postoperative analgesia in many lower abdominal procedures such as cesarean section. This study aimed to retrospectively compare the postoperative effects of TFP and TAP blocks for postoperative multimodal analgesia in patients who underwent cesarean section under spinal anesthesia. Methods: We retrospectively searched electronic medical records to identify patients who underwent cesarean section under spinal anesthesia between November 2021 and June 2022. A total of 497 patients were identified, and 120 patients were included that meet our criteria in our analysis. The patients were divided into three groups: TFP, TAP, and control. Data were obtained from the files of the patients. Results: The block groups had significantly lower numeric rating scale (NRS) scores, less non-steroidal anti-inflammatory drug consumption, and lower complications than the control group. No opioid consumption was observed in the block groups. Although no non-steroidal anti-inflammatory drug consumption until the 4th hour and no opioid consumption until the 8th hour were observed in the control group, the need for additional analgesics increased as time passed. While the TFP group needed analgesics later than the TAP group, the NRS scores and total analgesic consumption were lower (p<0.001). Patient satisfaction was higher in the block groups than in the control group (p<0.001). Conclusion: Transversalis fascia plane and TAP blocks are effective as part of multimodal analgesia in cesarean section. The TFP block is superior to the TAP block in terms of pain scores, additional analgesic requirements, and patient satisfaction. Keywords: Cesarean section, postoperative pain, ultrasound-guided regional anesthesia, transversus abdominis plane block, transversalis fascia plane block

Design and evaluation of UltRASim: An immersive simulator for learning ultrasound-guided regional anesthesia basic skills

Virtual reality shows great promise as a technology for training healthcare professionals within a secure simulated environment. This work presents the design, development, and assessment of UltRASim: an immersive simulator for ultrasound-guided regional anesthesia. First, task and skills analyses were performed with domain experts to build the task model of the procedure and determine the simulator’s learning objectives and design constraints. Then, a face and content validity study was conducted with eighteen anesthesiologists to assess the simulator’s prototype. The responses to seven of eleven face validity questions were predominantly positive, indicating a favorable reception. The primary concerns pertained to the fidelity of haptic feedback during needle insertion. This suggests incorporating a higher fidelity haptic device in future design iterations. Conversely, responses to all six questions related to the content validity were predominantly positive. Participants found that the simulator held significant potential as a training tool, particularly for developing hand–eye coordination skills. These findings validate several design choices and highlight areas for improvement in subsequent iterations of UltRASim before its formal validation as a training tool.

The Development, Implementation, and Evolution of an Emergency Medicine Ultrasound-guided Regional Anesthesia Curriculum.

Despite the inclusion of both diagnostic and procedural ultrasound and regional nerve blocks in the original Model of the Clinical Practice of Emergency Medicine (EM), there is no recommended standardized approach to the incorporation of ultrasound-guided regional anesthesia (UGRA) education in EM training. We developed and implemented a structured curriculum for both EM residents and faculty to learn UGRA in a four-hour workshop. Each Regional Anesthesia Anatomy and Ultrasound Workshop was four hours in length and followed the same format. Focusing on common UGRA blocks, each workshop began with an anatomist-led cadaveric review of the relevant neuromusculoskeletal anatomy followed by a hands-on ultrasound scanning practice for the blocks led by an ultrasound fellowship-trained EM faculty member, fellow, or a postgraduate year (PGY)-4 resident who had previously participated in the workshop. Learners identified the relevant anatomy on point-of-care ultrasound and reviewed how to conduct the blocks. Learners were invited to complete an evaluation of the workshop with Likert-scale and open-ended questions. In the 2020 academic year, six regional anesthesia anatomy and ultrasound workshops occurred for EM faculty (two sessions, N = 24) and EM residents (four sessions, N = 40, including a total of five PGY4s, 10 PGY3s, 12 PGY2s, and 13 PGY1s). Workshops were universally well-received by both faculty and residents. Survey results found that 100.0% of all responding participants indicated that they were "very satisfied" with the session. All were likely to recommend this session to a colleague and 95.08% of participants believed the session should become a required component of the EM curriculum. The use of UGRA is increasing, and and it critical in EM. An interdisciplinary approach in collaboration with anatomists on an interactive, nerve block workshop incorporating both gross anatomy review and hands-on scanning was shown to be well-received and desired by both EM faculty and residents.

Artificial intelligence in regional anaesthesia.

Ultrasound-guided regional anaesthesia is used to facilitate the real-time performance of the regional block, increase the block success and reduce the complication rate. Artificial intelligence (AI) has been studied in many medical disciplines with high success rates, especially radiology. The purpose of this article was to review the evolution of AI in regional anaesthesia. The role of AI is to identify and optimise the sonography image, display the target, guide the practitioner to advance the needle tip to the intended target and inject the local anaesthetic. AI supports non-experts in training and clinical practice and experts in teaching ultrasound-guided regional anaesthesia.

Patient Satisfaction With, and Outcomes of, Ultrasound-Guided Regional Anesthesia at a Referral Hospital in Tanzania: A Cross-Sectional Study.

Regional anesthesia techniques are increasingly used in high-income countries (HICs) for both surgical anesthesia and postoperative analgesia. However, regional anesthesia has not been utilized to the same degree in low- to middle-income countries (LMICs) due to a lack of resources and trained personnel. This study evaluates patient satisfaction with, and outcomes of, ultrasound-guided regional anesthesia for extremity surgery at Kilimanjaro Christian Medical Center (KCMC) in the Northeastern zone of Tanzania. Study patients were ≥18 years of age; American Society of Anesthesiologists (ASA) physical status I, II, or III; and underwent extremity surgery under peripheral nerve block with ultrasound guidance at KCMC. After placement, blocks were assessed for effectiveness intraoperatively, as demonstrated by the need for supplemental analgesic or sedative medication or conversion to a general anesthetic. Postoperatively, patients were assessed for satisfaction with their nerve block and pain at 12 and 24 hours. Adverse events related to regional anesthesia were assessed immediately, 45 minutes after block placement, and at 12 and 24 hours postoperatively. The primary outcome was patient satisfaction at 12 hours. Secondary outcomes were block success rate and analgesia at 12 and 24 hours postoperatively. A convenience sample of 170 patients was included in the study, of whom 156 (95% confidence interval [CI], 87-95) were either satisfied or very satisfied with their block. Block placement was highly successful with only 8 of 170 participants (95% CI, 2.4-8.3), requiring conversion to a general anesthetic. Analgesia continued in the postoperative period, with 164 of 170 (95% CI, 93-98) patients and 145 of 170 (95% CI, 80-90) patients reporting acceptable analgesia at 12 and 24 hours, respectively. No major adverse events, such as local anesthetic toxicity, infection, bleeding, nerve injury, or pneumothorax, were observed. Our study found that ultrasound-guided regional anesthesia in a resource-constrained setting was effective for extremity surgery and resulted in high patient satisfaction. No complications occurred. The use of ultrasound-guided regional anesthesia shows promise for the safe and effective care of patients undergoing extremity surgery in LMICs.

Implementation of an Ultrasound-Guided Regional Anesthesia Program in the Emergency Department of a Community Teaching Hospital

We sought to initiate an emergency department (ED)-based ultrasound-guided regional anesthesia (UGRA) program in our community teaching hospital system. Here, we present our development process and protocol. We also sought to assess the types, indications, and associated adverse event rates for the UGRA procedures in this study. We conducted a retrospective analysis of prospectively collected quality assurance data from a case series of patients who underwent an UGRA procedure in the ED. In August 2020, we developed an UGRA program for our community teaching hospital and its 2 affiliated freestanding EDs. For quality assurance purposes, we tracked all UGRA procedures performed in the ED, and we specifically assessed adverse events using structured follow-up. We subsequently obtained approval from our institutional review board to perform chart reviews of the patients in our dataset to abstract additional data and formally perform a research study. We determined the frequency with which different UGRA procedures were performed, and we calculated the adverse event rate. Between August 24, 2020, and July 15, 2022, a total of 18 different sonographers performed and documented 229 UGRA procedures on 206 unique patients. This included 28 different types of procedures. Follow-up after disposition was successful in 82.0% of patients. In 2 cases, the patient reported no pain relief at all from the procedure, but no patients reported complications related to the procedure. We successfully initiated a robust ED-based UGRA program in our community teaching hospital system. Among patients with successful follow-up, no adverse events were identified.

Nominal logistic regression analysis of variables determining needle visibility in ultrasound images – a full factorial cadaver study

BackgroundNeedle visualization is essential to avoid vascular puncture and nerve injury in ultrasound-guided regional anesthesia. Several factors that statistically influence needle visibility have been described but the dimensions of their individual impact remain unclear. This study aimed to quantify the impact of various independent factors on ultrasound needle visibility.MethodsA total of 1500 ultrasound videos of in-plane needle insertions were obtained in embalmed cadavers with ten different commercially available echogenic and non-echogenic needles at different insertion angles and bevel orientations in a full factorial study design. The visibility of needle tip and shaft were rated as “good” or “poor” visibility. Nominal logistic regression analyses were calculated for the visibility of the needle tip and shaft.ResultsSonoPlex Stim Sprotte, SonoTAP Facet (needle tip and shaft) and Spinostar PencilPoint (needle tip)), insertion angle and bevel orientation were associated with good ultrasound visibility, reaching statistical significance (p < 0.05). The range of the effect on the log-odds scale for needle tip visibility was largest for the insertion angle with 6.33, followed by the tissue condition (3.76), bevel orientation (1.45) and the needle types (1.25). Regarding the needle shaft visibility, the largest effect range was observed with the insertion angle (7.36), followed by the tissue conditions with 3.96, needle type (1.86) and bevel orientation (0.95).ConclusionIn-plane needle visibility in ultrasound images depends mainly on the insertion angle, as expected. This is closely followed by the tissue condition, which is a factor related to the patient, thus cannot be altered to improve needle visibility. In the dimensions of the log-odds scale, the choice of a specific needle is far less important towards achieving a good visualization, whereas optimizing the bevel orientation can have a larger impact than the needle choice. Concluding from the relative dimensions of factors that determine needle visibility in this model, the importance of needles with echogenic features may be overrated.

Bibliometrics and knowledge map analysis of ultrasound-guided regional anesthesia.

Through bibliometric analysis, we aim to comprehensively understand the research dynamics in this field, reveal key scientific research achievements and breakthrough discoveries, and provide valuable reference and guidance for future research directions. Utilizing the Web of Science, we retrieved the literature pertaining to ultrasonics-guided regional anesthesiology (1994-2022). CiteSpace and VOSviewer were used for bibliometric and knowledge mapping analysis. Our examination encompassed publication trends, authorship patterns, institutional contributions, frequently occurring keywords, keyword clustering, and emerging terminology trends. Of the 570 papers reviewed, there was a rising trend in publications each year. The main keywords in regional anesthesia were ultrasound guidance, nerve, analgesia, and pain score. Key research areas were regional anesthesia, ultrasound guidance, approach, pain score, and plane block. The U.S. led in research. Stanford University, University of Toronto, and Cork University Hospital were central institutions. Chan V was the top author with 24 articles, while Marhofer P was the most cited at 150 times. Regional anesthesia and pain medicine were the predominant journal in both publications and citations. In conclusion, research in this field consistently grew yearly, and visualization showcased trends in ultrasound-guided regional anesthesia. These visuals provided key bibliometric insights, helping researchers further explore and understand this domain.

Variability between human experts and artificial intelligence in identification of anatomical structures by ultrasound in regional anaesthesia: a framework for evaluation of assistive artificial intelligence

BackgroundScanNavTMAnatomy Peripheral Nerve Block (ScanNav™) is an artificial intelligence (AI)-based device that produces a colour overlay on real-time B-mode ultrasound to highlight key anatomical structures for regional anaesthesia. This study compares consistency of identification of sono-anatomical structures between expert ultrasonographers and ScanNav™. MethodsNineteen experts in ultrasound-guided regional anaesthesia (UGRA) annotated 100 structures in 30 ultrasound videos across six anatomical regions. These annotations were compared with each other to produce a quantitative assessment of the level of agreement amongst human experts. The AI colour overlay was then compared with all expert annotations. Differences in human–human and human–AI agreement are presented for each structure class (artery, muscle, nerve, fascia/serosal plane) and structure. Clinical context is provided through subjective assessment data from UGRA experts. ResultsFor human–human and human–AI annotations, agreement was highest for arteries (mean Dice score 0.88/0.86), then muscles (0.80/0.77), and lowest for nerves (0.48/0.41). Wide discrepancy exists in consistency for different structures, both with human–human and human–AI comparisons; highest for sartorius muscle (0.91/0.92) and lowest for the radial nerve (0.21/0.27). ConclusionsHuman experts and the AI system both showed the same pattern of agreement in sono-anatomical structure identification. The clinical significance of the differences presented must be explored; however the perception that human expert opinion is uniform must be challenged. Elements of this assessment framework could be used for other devices to allow consistent evaluations that inform clinical training and practice. Anaesthetists should be actively engaged in the development and adoption of new AI technology.

31 Safety of Ultrasound-Guided Regional Anesthesia Performed by Emergency Physicians: A Systematic Review of Adverse Events

31 Safety of Ultrasound-Guided Regional Anesthesia Performed by Emergency Physicians: A Systematic Review of Adverse Events

Exploring a Cadaver-Based Model for Teaching Emergency Medicine Residents Ultrasound-Guided Serratus Anterior Plane Blocks.

Background Ultrasound-guided regional anesthesia (USGRA) is increasingly being incorporated into ED clinical practice to provide pain control for a variety of traumatic injuries. The serratus anterior plane block (SAPB) has been shown to be effective at reducing intravenous opioid use and improving pulmonary function for patients with rib fractures, but there is limited prior research about how to safely teach this procedure to emergency medicine (EM) residents. Our goal was to examine the effect of a cadaver-based education model on EM residents' confidence in performing USGRA and provide a review of commonly encountered errors. Methods EM residents participated in a half-day cadaver-based education session that included a variety of less-commonly performed procedures including SAPB and fascia iliaca compartment block (FICB) USGRA. Residents received a didactic lecture and hands-on simulation practice during the month prior to the session. During the session, residents performed a SAPB and FICB on the cadaver patient using the same nerve block kit and ultrasound machine they would use for a living patient, with 1:1 supervision by an emergency ultrasound fellowship-trained physician who provided real-time feedback during the procedure. Representative ultrasound video clips were saved and reviewed. Surveys that were completed by residents after the session were analyzed. Results There were 23 residents who participated, and most had not performed any FICB (74%) or SAPB (87%) previously. The percentage of residents comfortable with general USGRA increased from 8.7% to 91.3% (p<0.001). Comfort with FICB increased from 9.1% to 77.3% (p<0.001), and comfort with SAPB increased from 9.1% to 77.3% (p<0.001). Instructors identified and corrected several common errors, such as overly aggressive needle insertion, instillation of air, and instillation of anesthetic into muscle rather than the fascial plane. Conclusion We found that a cadaver-based education model for teaching EM residents the SAPB and the FICB was associated with significant increases in resident confidence in performing the procedure and facilitated identification and correction of common procedural errors that may otherwise have gone undetected.

Augmented reality in ultrasound-guided regional anaesthesia: an exploratory study with potential implications for training

Augmented reality in ultrasound-guided regional anaesthesia: an exploratory study with potential implications for training