Finding Parts for Medical Product Design

I am looking to create a product similar to this seen in the video. [login to view URL] However we want to use easy find replaceable/refillable co2 cartridges like that used on the Soda Stream or places like that. Easily found local replacements or fills. I am looking to figure out the parts I need to connect the co2 cartridge. Then I assume we use a solenoid valve to allow the co2 to enter into the bag. So just an electronic switch. Then also need to source the valves need on the bag that are plastic quick connect. We will vacuum out the air first and then inject co2 into the bag covering the body part. I need some design ideas and to source out all parts that we need. I found these bags from Walgreens that could be used or if you can source out another place to purchase them. https://www.walgreens.com/store/c/walgreens-reusable-waterproof-cast--wound-protector-adult-arm/ID=prod6112459-product?ext=gooPLA_-_All_Products&pla&adtype=pla_with_promotion&kpid=sku6099131&sst=7bdf11f8-0455-42e3-babe-783a6ee0a3fd The product will be either manufactured in Pakistan or China. Thank you