Having taken courses in biomedical engineering, and done some research for a company looking to do what you describe, I can say with some certainty that it is v

Having taken courses in biomedical engineering, and done some research for a company looking to do what you describe, I can say with some certainty that it is very difficult to start a medical hardware company. You need to outsource production to an expensive certified CM with large expensive MOQs, unless you want to go through time consuming and expensive manufacturing approvals yourself (before being allowed to make or sell anything). You must also develop (easy) and have your device approved (hard), as well as not being allowed to change anything without additional time consuming and expensive approvals. Add in the fact that most diagnostic electronics require the highest level of scrutiny, paperwork, bureaucracy, and delays, and you quickly figure out that you're better off doing something else.