Oh, neither option is any good. How would you know the ventilation is related to your Covid use case and not drug overdose, surgery or some other reason people are ventilated?
The inner @Christian_Reich in the back of my head says “maybe someone would want” isn’t a use case. See his post about the “attic” approach.
A use case is a well defined question. Wait until you have one, then dig deep into the source data to find and ETL all relevant data to the CDM. We’ll be here to help 