We recently had the 3rd Tanzanian Conference on Emergency Medicine. Point of Care Ultrasound (PoCUS) training was one of the pre-conference workshops. Ultrasound-guided intravenous cannulation can be very challenging for many doctors in the emergency department.
Therefore, we had a station providing a real-time opportunity to practice IV access using our homemade ultrasound phantoms. And I shall share with you how we came up with this solution.
Ingredients
- A plastic container (dimensions used here 8 x 5.5 x 5inches)
- Long balloons
- Assorted food colors
- Gelatin
- Metamucil (psyllium)
- Powdered household detergent
- Spoon, sieve, hand mixer, measuring cup, cooking pot and cooker
- Filler syringes
- Gloves
How to make your mixture
Take a cooking pot and fill it with 1200 mls of water (we used this as our molding device could accommodate this amount of mls) bring it to a boil (just as it begins to form tiny bubbles on the base add gelatin powder 8 tablespoons and stir with a hand mixer until it completely dissolves. Thereby add 2 tablespoons of Metamucil and 1 tablespoon of detergent and continue stirring with low flame until the mixture begins to thicken. At this point, you will also see foam that sits on top of the mix. Use a sieve to get the foam out. You can, at this point, add any colors that you would want. Let the mixture cool a little before pouring it into the container. As it cools, you will notice it becoming thicker.
How to set-up your mold/containers
You will need to make a hole on both ends on the container using a hand drill or a hot pointed knife. For this case, since we didn’t have a drill, we used a knife with a pointed tip – heated it up in a burner until it was hot enough and used it to make holes through the plastic container using a circular motion. It is important for the holes not to be too big but estimated to the caliber/ diameter of the long balloons since we need just enough space to pass the balloons across.
For our case, we made 4 holes, 2 on each end. But you can do more if you want. You can arrange balloons in superficial or deeper locations.
To setup the vessels using the long balloons, you will need half cup of water and red color dye. Mix just enough to make a mixture that looks like blood. This can be filled in the balloons with a syringe. Since the color dye can stain your fingers, it is important to use gloves just to prevent your fingers from staining.
Tip: To make an artery, you can fill the balloon much more so that there is minimal compressibility and for the vein, you can fill just enough and have room for compressibility. Don’t fill the balloons before passing it through the container; if you do this, the filled balloon won’t manage to fit into the holes. Once fixed, tie both ends to make knots that are big enough to cover the seal the holes made.
Before pouring the mixture into the container, spray it with some oil, or you can use a cloth dip it in oil and apply it on the inside of the container.
After that, pour your mixture in the container and let it cool. You can place it in the refrigerator and use it the next day. We left ours for 24 hrs prior use.
You can use silicone seals at the holes if you notice to have any leaks. Otherwise, if you don’t have this, you can use plastic food wrap to create a seal between the balloon knots and the container just so the mixture does not leak out until it has set.
And finally, the images that you will have on ultrasound.
