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Hello,
The duration of procedures such as surgical operations and administration of anaesthesia is recorded in our source data. I was thinking of storing this information within the OBSERVATION table. But how do we link it back to the procedure performed on a particular patient, as there is only an association with the corresponding visit at present?
Regards,
Vimala
We use the fact relationship table:
5.13 FACT_RELATIONSHIP
The fact relationship table contains records to detail the relationships
between facts within one domain or across two domains, and the nature of
the relationship. Examples of types of fact relationships include: person
relationships (mother-child linkage), care site relationships (representing
the hierarchical organization structure of facilities within health
systems), drug exposures provided due to associated indicated condition,
devices used during the course of an associated procedure, and measurements
derived from an associated specimen. All relationships are directional, and
each relationship is represented twice symmetrically within the fact
relationship table. For example, two persons (PERSON_ID = 1 is the mother
of PERSON_ID = 2) have two fact relationships: 1- ‘PERSON_ID 1’ ‘parent of’
‘PERSON_ID 2’, and 2-‘PERSON_ID 2’ ‘child of’ ‘PERSON_ID 1’.
Apart from Don’s solution, which nobody likes, but is the only one we have right now, we are discussing addting time to all date fields, and end_date/time for observations and procedures. That way, you can do what you want to do. Till then, you have to do this workaround. However, no standard tool will know about that convention. So, unless you really want to do research on the duration, I’d just drop it. The OMOP CDM is not an attic of all data that might be useful one day. 