Hey John, sorry, not been hanging around here as much.
So, blockchain gets a lot of hype. A lot of the benefits - like immutability - are things you can arrange without the peer to peer network.
The core feature of blockchain as it’s presented in cryptocurrencies like Bitcoin is consensus (peers voting as to whether a given transaction is legit based on the prior record). Which (IMHO) is not largely required in medical records, with one notable exception, and that’s timestamps.
You can engage a digital notary service to provide you with verified timestamps (essentially you provide a hash derived from the record you are generating and they tack a timestamp onto it and sign it), but it seems a good fit for something that a lot of parties need and can form consensus on - that they did see a record submitted to the chain at such and such a time, enabling a concrete real-world timestamp to be established for the record.
It’s not required for things like e.g. non-repudiation of records. You can sign records with a private key you control, and no-one is going to dispute that your key signed those records.