EMS DAM Vocabulary Approach

Notes from call with co-chair Hamm on 9/4/2010

We have produced a DAM. It passed in May, but we have an update in this ballot. Now we are building a constrained model. Where possible, we want to go ahead and bind to the constrained model.

The source of requirements is NEMSIS, a NHTSA-funded organization. Our model pretty much translates their de facto standard, so there's not a whole lot of dynamic side analysis in the model. We added a handful of ideas from external sources, but not a lot. We aimed for international scope in R1, but gave it up over the summer; there's too much variability we're not being paid to model.

Our question is, what do we do?

We think this is our approach:

1. If a value set in NEMSIS can be mapped to one in HL7, use it. Bind it in the RMIM tool.

True

2. If a value set in NEMSIS can be mapped to values in some other standard, create a value set and submit it to HL7.

True; use the Harmonization template.
If Harmonization is moving to a rolling operation model (vs. scheduled meetings) how does that affect us? Or does it?
The form has a table listing how many codes and sets we're talking about: should they all be in one submission, or should we have one per set? 

3. If a value set in NEMSIS cannot be mapped to values in some other standard, create a value set referencing NEMSIS as its system (or some admixture) and submit it to HL7.

True: register NEMSIS. Try not to mix; have a good reason if we must. We can submit addition proposals to systems and then submit the harmonization request; we don't have to wait for SNOMED to reply.

Questions: Is that correct at the highest level? The Core Principles addresses a lot of conceptual issues, but it doesn't say anything about actually doing it.

For (1), we think we can actually do that.

For (2), how do we create a value set? Can it be Excel, or does it need to be some special format? What metadata do we need to include? Is there a template of some sort? Do referenced standards have to be from the Systems list, with OIDs, or can we refer to organizations not already in there? If HL7-recognized OIDs are required, how do we register the systems?

The Harmonization template doesn't provide a layout, but it does list the information needed. 

For (3), what criteria will be brought to bear on the sets? How do we get NEMSIS registered as a system? What would they be committing to?

Not committing to much more than they already do; just access to codes and permission to list them. 

For (2) and (3), if a value set has not yet been added to the repository, you can't bind it in the RMIM tool. How long should we expect that to take? Is there a way to include a "pending" binding?

Yes: we can include pending concepts. 

additional questions

If our set is similar to another, we might try to have the current owner modify it to meet our requirements; or, if it's a subset, create our "delta" set and then a "union"  set; or just create our own and be ready to defend it.

Yes, different instances of a concept in different value sets should be mapped to the same standard concept.

No, there are no best practices for choosing a SNOMED term if the concept seems to exist under different axes, apart from the obvious (semantics of the axis). Consistency would be good, if that helps.

Not answered yet: what if we need to postcoordinate something: can we and if so how? We could presumably use SNOMED guidelines to create an expression and put it in the "expression" property of CD in R2, but what about the CD value--both in the message and in the value set?