Final Design

We present a simulation that you can see, feel, and smell. 

Our final design decisions were made based on 3 user testing sessions with surgeons and doctors. We summarize the outcomes of our final design and components in this section. For further details, we highly encourage you to read our technical report which can be found in Internal -> Files. 

System overview of our design. Illustration showing the blood system and details on skin.

Our proposed systems overview includes a blood flow system, vasculature, tissue, sternocleidomastoid muscle, and skin.

Blood Flow System:

Our system relied on a cheap, easily available, submersible aquarium pump to provide pressure to the system. Upon user-testing, we have gathered feedback from surgeons to represent "realistic" blood flow pressure for neonatal patients. The arterial pressure is much higher than the venous pressure, and a bypass to prevent over-pressurization of the system during the simulation.

  Diagram of blood flow system showing flow through veins and arteries. 

Blood:

The blood in our simulation mimics the texture and viscosity of real blood. To add to the realistic experience of a medical simulation, we added a metallic smell element using iron powder. The recipe includes accessible ingredients: water, glycerin and food coloring. Detailed recipe is included in our report. 

Showing the designed blood

Vasculature:

We have chosen silicone tubing to mimic the vasculature. The silicone tubing varies for the veins and arteries. Artery tubing has thicker walls, a smaller diameter, and an opaque color. The inside of the tubing is slick to best represent the feeling of inserting a cannula during the procedure, and the tubing is easy to cut into 

 Vascular: artery (left) and vein (right)

Tissue:

Our tissue recipe has been inspired by makers in the casting communities. Primarily, we rely on an accessible and fast method called Ballistic Gel which involves heating and cooling glycerin and gelatin mixtures. Details of the methods utilized can be found in the report. 

  Glycerin and gelatin cast setting in the mold.

Muscle:

We have created the muscle using silicone caulking material, silicone pigment, and food coloring. This method is fairly easy and requires 15 minutes to dry. The muscle can be designed according to surgeon preferences. 

Making the muscle on a sheet 

Neck Collar: 

Design for the neck collar has been established by making sure that the surgeons have adequate room for cannulation while still preserving and maintaining anatomical difficulties. Primarily, this geometry is also constructed to provide an easier way to attach and secure the muscle in tension. 

                                                  Neck collar design which includes 3D printed mold and velcro straps.                                Neck collar with muscle secured around edges.

Skin:

The skin is made in three layers. The dermis layer is soft, strong, stretchy silicone that is dyed with flesh and brown colored silicone pigment. The fat layer is very soft platinum silicone rubber gel that is dyed with yellow silicone pigment. The muscle layer is a thin layer of Ecoflex 0030 dyed with blood-colored silicone pigment.

     Picture of skin with a focus on layers to make the skin (dermis, fat, and muscle layer)

Final Design Review at Rady Children's Hospital:

The photo was taken at Rady Children's Hospital during the final design review and demonstration.