Novice Learner In-Plane Ultrasound Imaging: Which Visualization Technique?

Accuracy of Ultrasound-Guided Needle Placement on the L5 Lumbar Nerve Root: A Cadaveric Study

OBJECTIVES

The aims of the study are to analyze and describe the accuracy of an ultrasound-guided approach to target the L5 root in cadaveric specimens and evaluate whether gender differences exist.

DESIGN

A cross-anatomical study on 40 cadaver L5 nerve roots was performed. A needle was introduced until contacting the L5 nerve root using ultrasound guidance. After that, specimens were frozen and studied by a cross-anatomical view to see the needle's path. The angulation, length, distance from the vertebral spine, the relevant ultrasound anatomical references, and the accuracy of the procedure were evaluated.

RESULTS

The needle tip reached the L5 root at a 72.5% rate. The mean angulation degrees of the needle relative to the skin surface were 75.53 ± 10.17 degrees, the length of the needle inserted was 5.83 ± 0.82 cm, and the distance from the vertebral spine to the point of entry of the needle was 5.39 ± 1.44 cm.

CONCLUSIONS

An ultrasound-guided technique can potentially be an accurate technique to perform invasive procedures on the L5 root. There were statistically significant differences between males and females in the length of the needle introduced. If the L5 root is not clearly visualized, ultrasound will not be the technique of choice.

Twelve tips for integrating ultrasound guided peripheral intravenous access clinical skills teaching into undergraduate medical education

Peripheral Intravenous access (PIV) is a procedure undertaken by Medical Practitioners and Non-Medical Practitioners. Traditional PIV uses a visual and tactile technique to locate blood vessels close to the surface of the skin. Chronic medical conditions, dehydration, obesity and recurrent intravenous access can make PIV challenging. Ultrasound (US) guided PIV is recommended to aid the identification of the arm arteries and veins and improve the success rate of needle placement in difficult cases. Medical and non-medical schools, and hospital organisations, are recognising the importance of US guided PIV education for undergraduate and postgraduate Medical and Non-Medical Practitioners. This to promote independence, efficiency and to improve patient safety. The aim of this 12 tips article is to highlight the considerations and practicalities of integrating and delivering, a practical based skills (PBS) session, on the use of US guided practice as an adjunct in difficult PIV, into the undergraduate medical education curricula.

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.

Development of a lateral ultrasound-guided approach for the proximal radial, ulnar, median and musculocutaneous (RUMM) nerve block in cats

OBJECTIVE

To describe a lateral ultrasound (US)-guided approach to the radial, ulnar, median and musculocutaneous (RUMM) nerves through a single proximal in-plane insertion in cats and to determine whether one or two injection points are required to successfully stain all the target nerves.

STUDY DESIGN

Prospective study.

ANIMALS

A total of eight client-owned healthy cats and 12 cat cadavers.

METHODS

In live cats, the US anatomy of the brachium, the landmarks and the site for needle accesses were determined. Then, 12 thawed feline cadavers were used to assess the spread of dye solution and nerve staining following the US-guided proximal-lateral-humeral RUMM injection using one and two injection points. Each cadaver was injected with 0.15 mL kg^-1 of a 0.25% new methylene blue solution in either a single injection aimed for the radial nerve of one limb (G1) or via two sites delivering 0.1 mL kg^-1 and 0.05 mL kg^-1 aimed for the radial and musculocutaneous nerves of the opposite limb, respectively (G2). Upon dissection, staining of the target nerves around their circumference for length of >1 cm was considered successful.

RESULTS

Sonoanatomy was consistent with anatomy upon dissection and target nerves were identified in all cadavers. Staining was 100% successful for the radial, median and ulnar nerves in both groups, and 41.7% and 100% for the musculocutaneous nerve in G1 and G2, respectively.

CONCLUSIONS AND CLINICAL RELEVANCE

This novel lateral US-guided approach for the proximal RUMM nerve block allowed a good identification of the nerves and related structures, and it provided a consistent muscular structure through which the needle could be easily guided. An injection performed in two aliquots (within the caudal and cranial compartments of the neurovascular sheath) appeared to be necessary to successfully stain all the target nerves.

Infraclavicular brachial plexus block in adults: a comprehensive review based on a unified nomenclature system

Over the last decade, considerable progress has been made regarding infraclavicular brachial plexus block (ICB) in adults, especially since the introduction of ultrasound guidance. The advancements in ICB have been attributed to the development of various approaches to improve the success rate and reduce complications. This has also necessitated a unified nomenclature system to facilitate comparison among different approaches. This review aimed to propose an anatomical nomenclature system by classifying ICB approaches into proximal and distal ones to aid future research and provide practice advisories according to recent updates. We also comprehensively discuss various aspects of this nomenclature system. Our review suggests that ultrasound-guided ICB should be categorized as an advanced technique that should be performed under supervision and dual guidance. For one-shot block, the conventional distal approach is still preferred but should be modified to follow ergonomic practice, with the arm in the proper position. For continuous ICB, the proximal approach is promising for reducing local anesthetic volume and increasing efficacy. Nevertheless, further studies are warranted in this direction. We provide practice advisories to maximize safety and minimize adverse events, and recommend designing future studies on ICB according to these findings based on the unified nomenclature system.

Ultrasound imaging in medical student education: Impact on learning anatomy and physical diagnosis

Ultrasound use has expanded dramatically among the medical specialties for diagnostic and interventional purposes, due to its affordability, portability, and practicality. This imaging modality, which permits real-time visualization of anatomic structures and relationships in vivo, holds potential for pre-clinical instruction of students in anatomy and physical diagnosis, as well as providing a bridge to the eventual use of bedside ultrasound by clinicians to assess patients and guide invasive procedures. In many studies, but not all, improved understanding of anatomy has been demonstrated, and in others, improved accuracy in selected aspects of physical diagnosis is evident. Most students have expressed a highly favorable impression of this technology for anatomy education when surveyed. Logistic issues or obstacles to the integration of ultrasound imaging into anatomy teaching appear to be readily overcome. The enthusiasm of students and anatomists for teaching with ultrasound has led to widespread implementation of ultrasound-based teaching initiatives in medical schools the world over, including some with integration throughout the entire curriculum; a trend that likely will continue to grow. Anat Sci Educ 10: 176-189. © 2016 American Association of Anatomists.

A Randomized Double-Blinded Trial on the Effects of Ultrasound Transducer Orientation on Teaching and Learning Ultrasound-Guided Regional Anesthesia

OBJECTIVES

Learning ultrasound-guided regional anesthesia skills, especially needle/ beam alignment, can be especially difficulty for trainees, who can often become frustrated. We hypothesized that teaching novices to orient the transducer and needle perpendicular to their shoulders will improve performance on a standardized task, compared to holding the transducer and needle parallel to the shoulders.

METHODS

This study compared the effects of transducer orientation on trainees' ability to complete a standardized ultrasound-guided nerve block simulation. The time to task completion and percentage of the attempt time without adequate needle visualization were measured. Participants were right-handed healthy adults with no previous ultrasound experience and were randomly assigned to training in either transducer and needle alignment in a coronal plane, parallel to the shoulders (parallel group) or transducer and needle alignment in a sagittal plane, perpendicular to the shoulders (perpendicular group). Participants used ultrasound to direct a needle to 3 targets in a standardized gelatin phantom and repeated this task 3 times. Their efforts were timed and evaluated by an assessor, who was blinded to group assignment.

RESULTS

Data were analyzed on 28 participants. The perpendicular group was able to complete the task more quickly (P < .001) and with a smaller proportion of time lost to inadequate needle visualization (P < .001).

CONCLUSIONS

Ultrasound-guided regional anesthesia trainees complete a standardized task more quickly and efficiently when instructed to hold the transducer and needle in an orientation perpendicular to their shoulders.

Evaluation of the eZono 4000 with eZGuide for ultrasound-guided procedures

Ultrasound-guided procedures are increasingly common in a variety of acute care settings, such as the operating room, critical care unit and emergency room. However, accurate judgment of needle tip position using traditional ultrasound technology is frequently difficult, and serious injury can result from inadvertently advancing beyond or through the target. Needle navigation is a recent innovation that allows the clinician to visualize the needle position and trajectory in real time as it approaches the target. A novel ultrasound machine has recently been introduced that is portable and designed for procedural guidance. The eZono 4000™ features an innovative needle navigation technology that is simple to use and permits the use of a wide range of commercially available needles, avoiding the inconvenience and cost of proprietary equipment. This article discusses this new ultrasound machine in the context of other currently available ultrasound machines featuring needle navigation.