@11122 Welcome to OHDSI!
In short, devices are the least standardized Domain in our vocabulary ecosystem. We usually just take what source vocabularies give to us in the Device domain and make them standard if they are valid in the source because it is impossible to standardize devices. Let’s say you have furosemide from Supplier A under Brand A1 and furosemide from Supplier B under Brand B1. It is still the same. But if you take the hemodialysis set from Supplier A, it is so much different from the hemodialysis set from Supplier B (coating, length, connectors, etc.)
Good news for you - most people don’t need to use devices to find peritoneal dialysis patients, because in OHDSI we have a very strong hierarchy of procedures, conditions, and observations.
Peritoneal dialysis, Peritoneal dialysis used, Peritoneal dialysis care, Complication of peritoneal dialysis - there are more, just use what you need.
I highly recommend you begin with the book of OHDSI and pay attention to the work of Phenotype Development and Evaluation Working Group.