Technical communication: new teaching model for practicing ultrasound-guided regional anesthesia techniques: no perishable food products!

Comparison of low-cost phantoms for ultrasound-guided fine-needle aspiration biopsy training

INTRODUCTION

Phantoms and simulators are widely accepted methods to gain valuable experience and confidence for inexperienced trainees prior to seeing their patient and for refining their skills. A phantom model that is durable, simple, and inexpensive to produce and use would be ideal to train practitioners in ultrasound-guided fine-needle aspiration biopsy (USFNA) technique.

MATERIALS AND METHODS

In this study, we systematically compared several low-cost phantom models including gelatin, extra firm tofu, canned cooked pork, ballistics gel, and chicken breast for their haptic properties, echogenicity, teaching utility, and overall performance based on a Likert scale (1-5; 5 = best). Nine cytopathologists and cytopathology fellows who perform FNA regularly evaluated these models and completed the survey.

RESULTS

The gelatin phantom, with a gelatin to water ratio of 1:8 by weight, was found to be the best for USFNA practice and overall performance, followed by the 1:10 gelatin phantom. Tofu and chicken breast phantoms were also good low-cost alternatives that needed only a few minutes of total preparation time.

CONCLUSIONS

Low-cost, homemade phantoms can serve as excellent alternatives to commercial phantoms for practicing and teaching USFNA.

A Simple, Realistic, Inexpensive Nerve Phantom

Ultrasound-guided nerve blocks are common techniques in several medical specialties. Phantoms are commonly used when teaching these procedures. Commercial phantoms are expensive, and most previously published "homemade" nerve phantoms have a substantial amount of posterior shadowing, making it difficult to visualize the needle posterior to the simulated nerve. We have constructed a simple and easy-to-make nerve block phantom using a hot dog core embedded in a gelatin-psyllium hydrophilic mucilloid fiber mixture that has little to no posterior shadowing.

Ultrasound-Guided Vascular Access Simulator for Medical Training: Proposal of a Simple, Economic and Effective Model

OBJECTIVE

To present a simple and affordable model able to properly simulate an ultrasound-guided venous access.

DESIGN

The simulation was made using a latex balloon tube filled with water and dye solution implanted in a thawed chicken breast with bones.

RESULTS

The presented model allows the simulation of all implant stages of a central catheter. The obtained echogenicity is similar to that observed in human tissue, and the ultrasound identification of the tissues, balloon, needle, wire guide and catheter is feasible and reproducible.

CONCLUSION

The proposed model is simple, economical, easy to manufacture and capable of realistically and effectively simulating an ultrasound-guided venous access.

Simulation in teaching regional anesthesia: current perspectives

The emerging subspecialty of regional anesthesiology and acute pain medicine represents an opportunity to evaluate critically the current methods of teaching regional anesthesia techniques and the practice of acute pain medicine. To date, there have been a wide variety of simulation applications in this field, and efficacy has largely been assumed. However, a thorough review of the literature reveals that effective teaching strategies, including simulation, in regional anesthesiology and acute pain medicine are not established completely yet. Future research should be directed toward comparative-effectiveness of simulation versus other accepted teaching methods, exploring the combination of procedural training with realistic clinical scenarios, and the application of simulation-based teaching curricula to a wider range of learner, from the student to the practicing physician.

A review of computer-based simulators for ultrasound training

SUMMARY STATEMENT

Computer-based simulators for ultrasound training are a topic of recent interest. During the last 15 years, many different systems and methods have been proposed. This article provides an overview and classification of systems in this domain and a discussion of their advantages. Systems are classified and discussed according to the image simulation method, user interactions and medical applications. Computer simulation of ultrasound has one key advantage over traditional training. It enables novel training concepts, for example, through advanced visualization, case databases, and automatically generated feedback. Qualitative evaluations have mainly shown positive learning effects. However, few quantitative evaluations have been performed and long-term effects have to be examined.

A review of the benefits and pitfalls of phantoms in ultrasound-guided regional anesthesia

With the growth of ultrasound-guided regional anesthesia, so has the requirement for training tools to practice needle guidance skills and evaluate echogenic needles. Ethically, skills in ultrasound-guided needle placement should be gained in a phantom before performance of nerve blocks on patients in clinical practice. However, phantom technology is varied, and critical evaluation of the images is needed to understand their application to clinical use. Needle visibility depends on the echogenicity of the needle relative to the echogenicity of the tissue adjacent the needle. We demonstrate this point using images of echogenic and nonechogenic needles in 5 different phantoms at both shallow angles (20 degrees) and steep angles (45 degrees). The echogenicity of phantoms varies enormously, and this impacts on how needles are visualized. Water is anechoic, making all needles highly visible, but does not fix the needle to allow practice placement. Gelatin phantoms and Blue Phantoms provide tactile feedback but have very low background echogenicity, which greatly exaggerates needle visibility. This makes skill acquisition easier but can lead to false confidence in regard to clinical ability. Fresh-frozen cadavers retain much of the textural feel of live human tissue and are nearly as echogenic. Similar to clinical practice, this makes needles inserted at steep angles practically invisible, unless they are highly echogenic. This review describes the uses and pitfalls of phantoms that have been described or commercially produced.