There is no practical way to do that. Seriously.
I agree. Well, you cannot get everything out and specific things like, say, SSN or more common health problems, can be blanked out with patterns. But misspell the name of the condition you have or describe it instead of using its name and you are already screwed in most cases. And names, quasi-identifiers of people, etc. are basically impossible to recognize reliably.
Hence what needs to be done here is also that anybody working on the data needs to be under oath to not leak any personal data and all processing must be done on isolated infrastructure. Obviously, that makes things slower and more expensive.