Development of low-cost ultrasound-guided cannulation models

Introduction Ultrasound-guided cannulation is a valuable clinical skill, however, commercial training models are often expensive, posing barriers for departments that cannot afford them and reluctance to loan models from those who can. To address this, we developed an affordable, effective model using agar-agar and latex balloons filled with ultrasound gel which replicates the ultrasound appearance and tactile feedback necessary for skill development. Methods We considered various materials for the primary medium, including meat, gelatin and agar-agar, ultimately selecting agar-agar for its favourable properties. Concentrations from 1 g/100 mL to 10 g/100 mL were tested. For mock vessels, we considered silicone and latex Foley catheters, as well as latex balloons filled with air, water or ultrasound gel. Drill bits of varying sizes were used to create openings in plastic containers for mock vessel insertion. The use of red dye was also explored to simulate flashback. Results The 8 g/100 mL agar-agar concentration provided the most realistic ultrasound appearance and resistance during cannulation. Higher concentrations resulted in a tough, crack-prone consistency, while lower concentrations lacked structural integrity. Adding 40 mL of disinfectant reduced mould and produced an opaque medium. Latex balloons filled with ultrasound gel demonstrated minimal shadowing and were easily inserted and removed. A 6 mm wood drill bit was used for creating suitable vessel insertion points. Conclusion This cost-effective model offers a valuable practical solution for simulating ultrasound-guided cannulation. Our step-by-step guide facilitates easy replication, meeting the need for affordable training tools in medical education and paving the way for further advancements in low-cost simulation models.