The American Society of Regional Anesthesia and Pain Medicine, the European Society of Regional Anaesthesia and Pain Therapy, and the Asian Australasian Federation of Pain Societies Joint Committee recommendations for education and training in ultrasound-guided interventional pain procedures

Practice 'safe scans': why ultrasound transducer covers should be considered best practice

Single-injection, ultrasound-guided nerve block procedures involve puncturing the skin in close proximity to an ultrasound transducer, creating a potential vector for transmission of microbial organisms when skin flora and blood come into contact with the probe. Practice patterns regarding disinfection of the transducer and the use of barrier protection are inconsistent, ranging from sterile sleeve probe covers to no cover at all. Although sleeve probe covers are easy and straightforward to use and serve to protect patients, providers and medical equipment, their utilisation remains controversial. Standardisation of their use eliminates the impact of improper or haphazard probe disinfection and makes infection control practices consistent and reproducible. This position is shared by multiple societies and authorities on ultrasound and acute care medicine. In this Daring Discourse, we outline the arguments supporting the utilisation of single-use sleeve probe covers to ensure patient safety with respect to vector-borne transmission of microbes during single-injection regional anaesthesia procedures.

Landmark-guided versus Real-time Ultrasound-guided Combined Spinal-epidural Anesthesia Techniques: Paramedian Sagittal Oblique and Transverse Interlaminar Approach

Background

There are different types of real-time ultrasound (US)-guided combined spinal epidural (CSE) anesthesia techniques. We aimed to investigate the effect of real-time US-guided paramedian sagittal oblique (PSO), transverse interlaminar (TI) approach method, and landmark-guided (LG) CSE anesthesia.

Methods

Ninety patients who underwent CSE block were included in the study. Patients were randomized into LG (n = 30), PSO (n = 30), and TI (n = 30) groups. The primary outcome was number of needle manipulations. The secondary outcomes are the number of attempts, needle visibility, procedure time, procedure success rate, catheter placement difficulty, posterior complex distance, and complications.

Results

The number of needle manipulations was statistically significantly lower in the LG technique group (P < 0.000). When the number of attempts, the difficulty of catheter placement, and the procedure's success rate were compared between the three groups, we did not find a statistically significant difference (P > 0.05). In addition, when the procedure times were compared, the time measured for the LG group was statistically significantly lower than in the PSO and TI groups (P < 0.000).

Conclusion

In the results of this study, the real-time US-guided CSE anesthesia application had a similar success and complication level with LG technique. The LG method had a shorter processing time and fewer needle manipulations.

Point-of-Care Ultrasound Educational Development in Australasia: A Scoping Review

Point-of-care ultrasound (PoCUS) technology is evolving rapidly and is being adopted by many health professionals in their clinical practice. Ultrasound is a complex skill requiring dedicated training. Appropriate integration of ultrasound education into medical, surgical, nursing and allied health professions is a current challenge worldwide. There are patient safety implications for use of ultrasound without adequate training and frameworks. The purpose of the review was to overview the status of PoCUS education in Australasia; investigate what is being taught and learned about ultrasound across the health professions; and identify potential gaps. The review was limited to postgraduate and qualified health professionals with established or emerging clinical use for PoCUS. A scoping review methodology was used to include literature in peer-reviewed articles, policies, guidelines, position statements, curricula and online material relating to ultrasound education. One hundred thirty-six documents were included. The literature revealed heterogeneity in ultrasound teaching and learning across the health professions. Several health professions lacked any defined scopes of practice, policies or curricula. Significant investment in resourcing ultrasound education is required to address the current needs in Australia and New Zealand.

Fascia Iliaca Blocks: A Cadaveric Study Comparing the Suprainguinal Approach to the Loss of Resistance Technique

Background Local anesthetic fascia iliaca blocks (FIB) are used for peri- and post-operative analgesia in hip fracture patients. The loss of resistance technique (LORT) and the suprainguinal approach (SIA) are two techniques commonly used. We present a pilot, first cadaveric study model that compares both techniques. Methods Methylene blue dye was injected as a local anesthetic substitute. This dye is easily visible. Both hips on each of the seven cadavers were injected with one of the two techniques used per side. Single-blinded randomization was conducted to determine the technique to be administered in each hip. Ten minutes after injection, the dissection of the femoral, obturator, and lateral femoral cutaneous nerves (LFCN) revealed the dye spread around these nerves. The SIA and the LORT were compared in their area of dye distribution using the Wilcoxon matched-pairs signed-rank test. The hips of a single cadaver were matched, since these received the injection via a different technique. Results The area of dye spread was greater in the SIA for five cadavers. Dye spread was greater following the LORT in two cadavers. However, the Wilcoxon matched-pairs signed-ranked test revealed no statistically significant difference in the area of dye spread following both techniques (p= 0.866). The SIA showed that the femoral, obturator, and LFCN were stained in six, three, and seven cadavers, respectively. The LORT resulted in five, two, and five of these nerves being stained, respectively. Conclusion This study found no statistically significant difference in terms of the area of dye spread between the SIA and the LORT. The number of nerves stained was greater following the SIA. This suggests that the SIA may lead to superior anesthetic outcomes. This conclusion is limited by the low sample size in this study. This work warrants the collection of more data through the same method to support or challenge our findings.

Ultrasound-guided regional anesthesia in COVID-19 and future pandemics: infection control

PURPOSE OF REVIEW

Infection control is inherent in ultrasound-guided regional anesthesia practice, because ultrasound transducer and coupling gel can be vectors for pathogen transmission. We reviewed the current standards and recommendations of ultrasound transducer cleaning, disinfection, and safe handling of ultrasound equipment. Based on the available data, we propose a set of practical recommendations applicable to coronavirus disease 2019 (COVID-19) pandemic and future epidemics.

RECENT FINDINGS

Regional anesthesia is often preferred over general anesthesia for COVID-19 patients. Avoidance of general anesthesia reduces the need for aerosol generating procedures. Administration of ultrasound-guided regional anesthesia and surgery under regional anesthesia in COVID-19 patients requires careful infectious precautions to prevent the viral spread through the use equipment.

SUMMARY

Ultrasound machine, transducer and coupling gel can serve as a vector for transmission of pathogens. In the era of COVID-19 pandemic, standardized strategies are recommended to minimize the risk of spread of COVID-19 to both patients and the healthcare providers.

Ultrasound-guided regional anesthesia: feasibility and effectiveness of teaching via telesimulation in Ethiopia

BACKGROUND

Acute pain management in resource-poor countries remains a challenge. Ultrasound-guided regional anesthesia is a cost-effective way of delivering analgesia in these settings. However, for financial and logistical reasons, educational workshops are inaccessible to many physicians in these environments. Telesimulation provides a way of teaching across distance by using simulators and video-conferencing software to connect instructors and students worldwide. We conducted a prospective study to determine the feasibility of ultrasound-guided regional anesthesia teaching via telesimulation in Ethiopia.

METHODS

Eighteen Ethiopian orthopedic and emergency medicine house staff participated in telesimulation teaching of ultrasound-guided femoral nerve block. This consisted of four 90-min sessions, once per week. Week 1 consisted of a precourse test and a presentation on aspects of performing a femoral nerve block, weeks 2 and 3 were live teaching sessions on scanning and needling techniques, and in week 4, the house staff undertook a postcourse test. All participants were assessed using a validated Global Rating Scale and Checklist.

RESULTS

Participants were provided with a validated checklist and global rating scale as a pretest and post-test. The participants showed significant improvement in their test scores, from a total mean of 51% in the pretest to 84% in their post-test.

CONCLUSIONS

Teaching ultrasound-guided regional anesthesia of the femoral nerve remotely via telesimulation is feasible. Telesimulation can greatly improve the accessibility of ultrasound-guided regional anesthesia teaching to physicians in remote areas.

American Society of Regional Anesthesia and Pain Medicine expert panel recommendations on point-of-care ultrasound education and training for regional anesthesiologists and pain physicians-part I: clinical indications

Point-of-care ultrasound (POCUS) is a critical skill for all regional anesthesiologists and pain physicians to help diagnose relevant complications related to routine practice and guide perioperative management. In an effort to inform the regional anesthesia and pain community as well as address a need for structured education and training, the American Society of Regional Anesthesia and Pain Medicine (ASRA) commissioned this narrative review to provide recommendations for POCUS. The guidelines were written by content and educational experts and approved by the Guidelines Committee and the Board of Directors of the ASRA. In part I of this two-part series, clinical indications for POCUS in the perioperative and chronic pain setting are described. The clinical review addresses airway ultrasound, lung ultrasound, gastric ultrasound, the focus assessment with sonography for trauma examination and focused cardiac ultrasound for the regional anesthesiologist and pain physician. It also provides foundational knowledge regarding ultrasound physics, discusses the impact of handheld devices and finally, offers insight into the role of POCUS in the pediatric population.

Along or across the visual axis: a comparison of two ultrasound screen, needle and transducer orientation techniques

OBJECTIVE

To evaluate two transducer and needle handling methods, along the visual axis (AL) and across the visual axis (AC), in non-skilled and skilled clinicians.

STUDY DESIGN

Prospective randomized crossover study.

METHOD

A total of 26 students with no ultrasound locoregional anaesthesia experience (non-skilled group) and six clinicians experienced and familiar with ultrasound locoregional anaesthesia (skilled group) were enrolled. The non-skilled group was asked to perform two tasks: the first on a phantom and the second on canine cadavers, whilst the skilled group performed only the second task. The tasks consisted of guiding the tip of the needle to a target point (simulated nerve on the jelly phantom and sciatic nerve on the cadavers) using two different methods of needle handling-AL or AC. All operators performed each task three times for each method. The time to drive the needle to the target for the two methods was analysed with a paired Student t test, and the number of times the needle was not visualized on the screen between the groups was compared using an unpaired Student t test. Data are presented as mean ± standard deviation. Value of p < 0.05 was considered significant.

RESULTS

The AL method, compared with the AC method, resulted in shorter performance time in both skilled (9 ± 5 versus 20 ± 8 seconds for the second task) and non-skilled groups (9 ± 8 versus 17 ± 15 seconds for the first task and 18 ± 11 versus 32 ± 26 seconds for the second task).

CONCLUSION AND CLINICAL RELEVANCE

In both groups, the AL method significantly reduced the time to complete the task. Results from this study indicate that the AL method should be the preferred method for learning/teaching ultrasound-guided regional anaesthesia.

Interscalene brachial plexus nerve block in the emergency department: an effective and practice-changing workshop

Background

The interscalene brachial plexus nerve block (ISNB) is a potentially useful method of regional analgesia for humerus fracture and shoulder dislocation reduction in the Emergency Department (ED). We examined the effectiveness of an ISNB workshop given to emergency medicine (EM) residents. We also explored complication rates and effectiveness of ISNBs performed in the ED.

Methods

One-hour evidence-based ISNB workshops were conducted with EM residents. Participants were given pre-, post-, and 3-month post-workshop knowledge and technical assessments. Results were analyzed using descriptive statistics. A pre- and post-workshop chart review examined ISNB utilization, complications, post-ISNB opiate administration, and post-ISNB procedural sedation.

Results

41 residents enrolled in the workshop. Pre-workshop pass rate: knowledge assessment 22%. Immediate post-workshop pass rates: knowledge assessment 100%, image acquisition 93%, needle placement 100%. Three months post-workshop pass rates: knowledge assessment 73%, image acquisition 76%, needle placement 100%. Areas of poorest knowledge retention were anatomical landmarks, block distribution, and early signs of LAST. In the chart review, 2 ISNBs were performed in the pre-workshop period, and 12 in the post-workshop period. No serious complications were recorded. 78.5% of attempted ISNBs were successful, without need for procedural sedation. Of the 11 successfully performed ISNBs, 91% received no opiates after the procedure.

Conclusions

Our study suggests that EM residents can learn the ISNB, perform it safely in the emergency department, and that the ISNB may be an alternative to procedural sedation and opiate use for shoulder dislocation. Residents are adept at ISNB technical skills but demonstrate some deficits in knowledge retention.

Echo-guided invasive pain therapy: indications and limitations

PURPOSE OF REVIEW

The purposes of this review are to summarize the advantages and limitations of ultrasound-guided pain interventions, and to illustrate those interventions with peripheral, axial and musculoskeletal pain procedures.

RECENT FINDINGS

With the capability of locating the interfascial plane, ultrasonography has led to the emergence of a series of plane blocks for the thoracoabdominal region in the recent decade.Ultrasonography for musculoskeletal procedures has been of growing interest because of the major advantage of direct visualization and scanning of various soft tissues and real-time spread in the injectate, thereby enhancing precision and efficacy, reducing risk of trauma and avoidance of radiation. For spine and intra-articular structures, ultrasonography is complicated by the bony shadow artefact and often deep location of the structure, making acquisition of ultrasound image challenging. Despite these difficulties, there is growing interest in applying ultrasonography for cervical spine and sacroiliac joint procedures.

SUMMARY

Pain intervention under ultrasound guidance is particularly valuable in peripheral and musculoskeletal procedures. There is growing interest of its application in cervical spine and sacroiliac joint. More outcome studies are required in the future to make ultrasound-guided pain intervention as the established procedure.

The efficacy of cervical spine phantoms for improving resident proficiency in performing ultrasound-guided cervical medial branch block: A prospective, randomized, comparative study

BACKGROUND

Few studies have been conducted on the utility of cervical spine phantoms for practicing cervical procedures. Here, we describe a simple method for creating a cervical spine phantom and investigate whether the use of a gelatin-based phantom is associated with improved proficiency in performing ultrasound-guided cervical medial branch block.

METHODS

A cervical spine phantom was prepared using a cervical spine model immersed in a mixture of gelatin and psyllium husk. In total, 27 participants, inexperienced in spinal ultrasonography, were enrolled and allocated to 1 of 2 groups (training group, n = 18; control group, n = 9). All participants were tested (test-1) following an introductory course of basic ultrasonography. Participants in the control group were tested again after 1 week (test-2). Those in the training group received a further individual 3-hour training session, and were tested again after 1 week (test-2).

RESULTS

The mean performance score in test-1 was 62.5 ± 10.1 points in the training group and 62.3 ± 4.1 points in the control group [95% confidence interval (95% CI) -5.5 to 5.8; P = .954]. In test-2, the mean score was 86.8 ± 6.5 points and 59.9 ± 4.4 points in the training and control groups, respectively (95% CI 21.9-31.8; P < .001). The mean time required to complete test-1 was 84.6 ± 26.6 seconds in training group and 90.7 ± 43.9 seconds in the control group (95% CI -34.0 to 21.7; P = .653); in test-2, the time required was 56.6 ± 27.9 and 91.2 ± 43.8 seconds (95% CI -63.0 to -6.2; P = .019), respectively. Interobserver reliability showed excellent agreement based on the intraclass correlation coefficient, and moderate to almost perfect agreement by kappa statistics.

CONCLUSION

Training using a gelatin-based cervical spine phantom helps novices acquire the skills necessary to perform ultrasound-guided cervical medial branch blocks.

Teaching concepts in ultrasound-guided regional anesthesia

PURPOSE OF REVIEW

Ultrasound-guided regional anesthesia is a challenging, complex skill and requires competence in teaching. The aim of this study was to review current literature on identification of education and learning of ultrasound-guided regional anesthesia and to summarize recent findings on teaching concepts.

RECENT FINDINGS

Several teaching programs have been described and implemented into daily routine. Factors relevant to current practice are the knowledge of sonoanatomy, the acquisition of manual skills, the teaching ability, and the feedback given to the trainee. Simulation is a rapidly growing field and is supported by the development of phantoms. Needle visualization is one of the core competencies that is necessary for successful ultrasound-guided procedures and could be supported by technical developments in the future to improve teaching concepts.

SUMMARY

Although a lot of key questions cannot be answered by the latest study results, some interesting findings were able to improve existing education programs. These results should be tailored to the individual need of a trainee, and the effects of improved training programs on patient safety and quality of care have to be investigated. The see one, do one, teach one approach is obsolete and should be abandoned.

Suprascapular block associated with supraclavicular block: An alternative to isolated interscalene block for analgesia in shoulder instability surgery?

BACKGROUND

Interscalene brachial plexus block (ISB) is the gold standard for postoperative pain management in shoulder surgery. However, this technique has side effects and potentially serious complications. The aim of this study was to compare the combinations of ultrasound-guided suprascapular (SSB) associated with supraclavicular nerve block (SCB) and ultrasound-guided ISB for postoperative analgesia after shoulder instability surgery.

METHODS

Sixty ASA physical status I-II patients scheduled to undergo shoulder instability surgery were included. Two groups: (i) the SSB+SCB group (n=30) in which the patients received a combination of US-guided SSB (15mL of bupivacaine 0.25%) and US-guided SCB (15mL of bupivacaine 0.25%) and (ii) the ISB group (n=30) in which the patients received US-guided ISB with 30mL of bupivacaine 0.25%. General anesthesia was administered to all patients. During the first 24h, the variables assessed were time to administer the anesthesia, duration of the analgesia, onset and duration of motor and sensory blockade, opioid consumption, cardiovascular stability, complications, and patient satisfaction.

RESULTS

Anesthesia induction took more time for the SSB+SCB group than for the ISB group. However, the onset time of motor and sensory blockade was similar in the two groups. Statistical analysis of the visual analog postoperative pain scoring at H0, H6, H12, and H24 showed nonsignificant differences between the groups. Analgesia, the first request for morphine, and total morphine consumption during the first 24h was similar in both groups. No complication was recorded in the SSB+SCB group. However, phrenic nerve block occurred in all patients in the ISB group.

CONCLUSION

US-guided SCB combined with US-guided SSB was as effective as ISB for postoperative analgesia after shoulder instability surgery without decreasing potential side effects.

TRIAL REGISTRATION

NCT identifier: NCT02397330.

Focused Training for Humanitarian Responders in Regional Anesthesia Techniques for a Planned Randomized Controlled Trial in a Disaster Setting

Background:Lower extremity trauma during earthquakes accounts for the largest burden of geophysical disaster-related injuries. Insufficient pain management is common in disaster settings, and regional anesthesia (RA) has the potential to reduce pain in injured patients beyond current standards. To date, no prospective research has evaluated the use of RA in a disaster setting. This cross-sectional study assesses knowledge translation and skill acquisition outcomes for lower extremity RA performed with and without ultrasound guidance among a cohort of Médecins Sans Frontières (MSF) volunteers who will function as proceduralists in a planned randomized controlled trial evaluating the efficacy of RA for pain management in an earthquake setting.

Methods:Generalist humanitarian healthcare responders, including both physicians and nurses, were trained in ultrasound guided femoral nerve block (USGFNB) and landmark guided fascia iliaca compartment block (LGFICB) techniques using didactic sessions and interactive simulations during a one-day focused course. Outcome measures evaluated interval knowledge attainment and technical proficiency in performing the RA procedures. Knowledge attainment was assessed via pre- and post-test evaluations and procedural proficiency was evaluated through monitored simulations, with performance of critical actions graded by two independent observers.

Results:Twelve humanitarian response providers were enrolled and completed the trainings and assessments. Knowledge scores significantly increased from a mean pre-test score of 79% to post-test score of 88% (p<0.001). In practical evaluation of the LGFICB, participants correctly performed a median of 15.0 (Interquartile Range (IQR) 14.0-16.0) out of 16 critical actions. For the USGFNB, the median score was also 15.0 (IQR 14.0-16.0) out of 16 critical actions. Inter-rater reliability for completion of critical actions was excellent, with inter-rater agreement of 83.3% and 91.7% for the LGFICB and USGFNB evaluations, respectively.

Discussion:Prior to conducting a trial of RA in a disaster setting, providers need to gain understanding and skills necessary to perform the interventions. This evaluation demonstrated attainment of high knowledge and technical skill scores in both physicians and nurses after a brief training in regional anesthesia techniques. This study demonstrates the feasibility of rapidly training generalist humanitarian responders to provide both LGFICB and USGFNB during humanitarian emergencies.

Regional Anesthesia for Painful Injuries after Disasters (RAPID): study protocol for a randomized controlled trial

Background

Lower extremity trauma during earthquakes accounts for the largest burden of disaster-related injuries. Insufficient pain management is common in resource-limited disaster settings, and regional anesthesia (RA) may reduce pain in injured patients beyond current standards of care. To date, no controlled trials have been conducted to evaluate the use of RA for pain management in a disaster setting.

Methods/design

The Regional Anesthesia for Painful Injuries after Disasters (RAPID) study aims to evaluate whether regional anesthesia (RA), either with or without ultrasound (US) guidance, can reduce pain from earthquake-related lower limb injuries in a disaster setting. The proposed study is a blinded, randomized controlled equivalence trial among earthquake victims with serious lower extremity injuries in a resource-limited setting. After obtaining informed consent, study participants will be randomized in a 1:1:1 allocation to either: standard care (parenteral morphine at 0.1 mg/kg); standard care plus a landmark-guided fascia iliaca compartment block (FICB); or standard care plus an US-guided femoral nerve block. General practice humanitarian response providers who have undergone a focused training in RA will perform nerve blocks with 20 ml 0.5 % levobupivacaine. US sham activities will be used in the standard care and FICB arms and a normal saline injection will be given to the control group to blind both participants and nonresearch team providers. The primary outcome measure will be the summed pain intensity difference calculated using a standard 11-point Numerical Rating Scale reported by patients over 24 h of follow-up. Secondary outcome measures will include overall analgesic requirements, adverse events, and participant satisfaction.

Discussion

Given the high burden of lower extremity injuries in the aftermath of earthquakes and the currently limited treatment options, research into adjuvant interventions for pain management of these injuries is necessary. While anecdotal reports on the use of RA for patients injured during earthquakes exist, no controlled studies have been undertaken. If demonstrated to be effective in a disaster setting, RA has the potential to significantly assist in reducing both acute suffering and long-term complications for survivors of earthquake trauma.

Trial registration

ClinicalTrials.gov (NCT02698228), registered on 16 February 2016.

COMPARISON OF ULTRASOUND-GUIDED VS. STANDARD LANDMARK TECHNIQUES FOR TRAINING NOVICE OPERATORS IN PLACING NEEDLES INTO THE LUMBAR SUBARACHNOID SPACE OF CANINE CADAVERS

The standard technique for placing a needle into the canine lumbar subarachnoid space is primarily based on palpation of anatomic landmarks and use of probing movements of the needle, however, this technique can be challenging for novice operators. The aim of the current observational, prospective, ex vivo, feasibility study was to compare ultrasound-guided vs. standard anatomic landmark approaches for novices performing needle placement into the lumbar subarachnoid space using dog cadavers. Eight experienced operators validated the canine cadaver model as usable for training landmark and ultrasound-guided needle placement into the lumbar subarachnoid space based on realistic anatomy and tissue consistency. With informed consent, 67 final year veterinary students were prospectively enrolled in the study. Students had no prior experience in needle placement into the lumbar subarachnoid space or use of ultrasound. Each student received a short theoretical training about each technique before the trial and then attempted blind landmark-guided and ultrasound-guided techniques on randomized canine cadavers. After having performed both procedures, the operators completed a self-evaluation questionnaire about their performance and self-confidence. Total success rates for students were 48% and 77% for the landmark- and ultrasound-guided techniques, respectively. Ultrasound guidance significantly increased total success rate when compared to the landmark-guided technique and significantly reduced the number of attempts. With ultrasound guidance self-confidence was improved, without bringing any significant change in duration of the needle placement procedure. Findings indicated that use of ultrasound guidance and cadavers are feasible methods for training novice operators in needle placement into the canine lumbar subarachnoid space.

Resident-Perceived Benefit of a Diagnostic and Interventional Musculoskeletal Ultrasound Curriculum: A Multifaceted Approach Using Independent Study, Peer Teaching, and Interdisciplinary Collaboration

Musculoskeletal ultrasound (MSUS) training is now a required component of physiatry residency, but formal curriculum guidelines are not yet required or established. The authors' objective was to assess the educational value of a collaborative residency MSUS training program. The authors designed a structured MSUS training curriculum for residents based on the authors' experience and previous literature. Twenty-five residents participated in this MSUS curriculum designed by faculty and chief residents. Resident volunteers were trained by the faculty as "table trainers" who taught their peers in small groups. Hands-on MSUS training sessions were led by a Physical Medicine and Rehabilitation faculty MSUS expert. A Likert scale-formatted questionnaire assessed resident-perceived value of the curriculum. Response rate was 96% (22 of 23). Self-reported MSUS knowledge comparing precurriculum and postcurriculum implementation resulted in significant improvement (P = 0.001). Peer teaching was highly valued, with 86% of residents rating it "very" or "extremely" beneficial (mean [SD] score, 3.9 [1.1]). Self-guided learning, by supplemental scanning and reading, was rated "beneficial" or "very beneficial" by 73% of residents (3.0 [0.7]). The authors' successful pilot program may serve as a teaching model for other residency programs.

Investigation of current infection-control practices for ultrasound coupling gel: a survey, microbiological analysis, and examination of practice patterns

BACKGROUND AND OBJECTIVES

Ultrasound coupling gel may serve as a vector for the spread of bacteria and has been the causative agent for significant health care-associated infections. The purpose of this study was to document existing infection-control procedures and level of contamination present within nonsterile ultrasound gel from several clinical departments at a single institution. A second purpose was to examine the effectiveness of clinician education and manufacturer-based ultrasound additives on ultrasound gel contamination and in vitro bacterial proliferation, respectively.

METHODS

Compliance with Health Canada recommended infection-control policies were determined by survey. Contamination of in-use ultrasound gel bottles was determined by inspecting cultures after 72 hours of incubation. After infection-control education, a 28-day interval assessment was used to examine contamination rates in newly provided ultrasound gel. The ability of ultrasound gel containing parabens to prevent bacterial growth was examined in cultures grown with and without ultrasound gel.

RESULTS

Practitioners were not compliant with Health Canada recommendations, but the baseline ultrasound gel contamination rate within these departments was only 2.5%. Education in infection control did not improve the contamination rate over 28 days. Contamination was discovered in ultrasound gel supplied directly from the manufacturer. Ultrasound gel suppressed but did not prevent bacterial growth in a species- and time-specific manner.

CONCLUSIONS

The source of contamination for in-use ultrasound gel may be of manufacturer or human origin. Because additives to the ultrasound gel are not bactericidal, sterile ultrasound gel should be used for invasive and high-risk cases, and improving infection-control policies is warranted.

Review of essential understanding of ultrasound physics and equipment operation

Ultrasound (US) is being extensively used an imaging tool in regional anesthesia (RA) and pain practice. Although it was first used in a regional block in 1978, it was only in 1994 that the first direct use of US in RA was reported. Like any other medical tool, its utility is only realized when the performing physician is able to understand the principles behind its application. Efficient use of US also requires an understanding of physical variables which can be suitable modified to produce a clear image of the structure of importance. This brief narrative review summarises the advantages of US in RA and pain practice over the conventionally used localising or imaging tools. The second section deals with the physics behind US. It highlights the necessary physical concepts such as wavelength, frequency and generation of US waves. It also informs the reader about the possible US and tissue interactions, use of US transducers and their differences. The third section deals with understanding the control variables in a typical US machine and how they could be modified to improve the image quality. The final section highlights the various artifacts that could be associated.

Ultrasonography of the cervical spine: an in vitro anatomical validation model

BACKGROUND

Anatomical validation studies of cervical ultrasound images are sparse. Validation is crucial to ensure accurate interpretation of cervical ultrasound images and to develop standardized reliable ultrasound procedures to identify cervical anatomical structures. The aim of this study was to acquire validated ultrasound images of cervical bony structures and to develop a reliable method to detect and count the cervical segmental levels.

METHODS

An anatomical model of a cervical spine, embedded in gelatin, was inserted in a specially developed measurement device. This provided ultrasound images of cervical bony structures. Anatomical validation was achieved by laser light beams projecting the center of the ultrasound image on the cervical bony structures through a transparent gelatin.

RESULTS

Anatomically validated ultrasound images of different cervical bony structures were taken from dorsal, ventral, and lateral perspectives. Potentially relevant anatomical landmarks were defined and validated. Test/retest analysis for positioning showed a reproducibility with an intraclass correlation coefficient for single measures of 0.99. Besides providing validated ultrasound images of bony structures, this model helped to develop a method to detect and count the cervical segmental levels in vivo at long-axis position, in a dorsolateral (paramedian) view at the level of the laminae, starting from the base of the skull and sliding the ultrasound probe caudally.

CONCLUSIONS

Ultrasound bony images of the cervical vertebrae were validated with an in vitro model. Anatomical bony landmarks are the mastoid process, the transverse process of C1, the tubercles of C6 and C7, and the cervical laminae. Especially, the cervical dorsal laminae serve best as anatomical bony landmarks to reliably detect the cervical segmental levels in vivo.

Sonographically guided costotransverse joint injections: a computed tomographically controlled cadaveric feasibility study

OBJECTIVES

The primary purpose of this study was to describe and validate a novel sonographically guided costotransverse (CTRV) joint injection technique.

METHODS

The bilateral T3-T10 CTRV joints of an unembalmed cadaveric specimen were localized using a 12-3-MHz linear array transducer. A 22-gauge, 2.5-in spinal needle was directed into the CTRV joint using an in-plane, lateral-to-medial approach under direct sonographic guidance. After needle placement, 3-dimensional computed tomographic (CT) images were obtained to assess the locations of the needle tips. This step was followed by injection of an iodinated contrast agent and repeated CT to assess the contrast flow pattern. An experienced musculoskeletal radiologist reviewed the CT images and assessed the accuracy of the injections (intra- or extra-articular). For intra-articular injections, a quantitative assessment of the percentage of injectate within the joint was performed.

RESULTS

A total of 16 sonographically guided CTRV joint injections were completed on a single torso-pelvis specimen. Using our technique, 11 of 16 sonographically guided CTRV joint injections (68.8%) placed the contrast agent into the target joint. Quantitative analysis of the arthrograms showed 6 of 11 intra-articular injections (54.5%) with greater than 50% injectate within the joint capsule.

CONCLUSIONS

To our knowledge, this study is the first to determine the feasibility of sonographically guided CTRV joint injections. Overall, 68.8% of injection attempts produced acceptable CTRV joint arthrograms, which compares favorably to a previously reported 76% accuracy rate for fluoroscopically guided CTRV joint injections. Although these injections are technically challenging, the use of sonographic guidance to perform CTRV joint injections is feasible and warrants further investigation to establish its role in the management of patients presenting with thoracic pain syndromes.