FHIR Chat · FHIR Workflow - Message, Transaction or contained

Stream: IG creation

Topic: FHIR Workflow - Message, Transaction or contained

Kevin Mayfield (Aug 25 2021 at 05:00):

We are being asked to define a series of FHIR Workflows. This is relatively greenfield area as we haven't defined any national UK standards in any previous versions of HL7 (not exactly true but close)

The rough payload pattern we are seeing is

1..1 focus Resource (for both request and event)
1..* PractitionerRole
1..1 Patient

Each of these payloads will have a create, update and maybe delete. It's roughly CRUD focused around a single resource.

So our options are

transaction - we're probably not POSTing direct to a server, it's up to the recipient to decide wether the PractitionerRole or Patient is a POST or PUT. Don't think this is the answer
use contained - not FHIR conformant and I think it makes handling the payload more difficult.
FHIR Message - this fits but getting lot of push back from technical staff who want a more RESTful approach.

Kevin Mayfield (Aug 25 2021 at 05:04):

We've gone down a FHIR Message route but wondering if I can make this more restful. e.g.

Move the POST /$process-message to POST {resource}/$process-message
(with a slim MessageHeader)

Kevin Mayfield (Aug 25 2021 at 05:10):

So our current prescription-order message is now sent to

POST /MedicationRequest/$process-message

Wondering also if we should add in CRUD as a parameter. To get something like

POST /MedicationRequest/$process-message?method=create

Kevin Mayfield (Aug 25 2021 at 05:50):

Looking at https://build.fhir.org/ig/HL7/davinci-ehrx/exchanging.html

We could swap to batch but we have a definition of the Bundled resources (MessageDefinition). Think we are in a half way house between message and batch?

Lloyd McKenzie (Aug 25 2021 at 13:59):

Can you explain how what you're trying to do is distinct from a simple RESTful upsert?

Kevin Mayfield (Aug 26 2021 at 07:10):

Sending several resources at once? The answer is FHIR Message but having a lot of push back against this.

John Moehrke (Aug 26 2021 at 11:11):

The use of Batch would likely make your RESTful zelots happy. You could profile the Batch so that the contents of the Bundle are well formed. Thus it is just a Bundle full of RESTful interactions. (IHE has a few of these). Now include in that profile of the Batch that the first resource just happens to be a MessageHeader that explains from who the content is from, to who the content should go, and why... and you have everyone happy.

Lloyd McKenzie (Aug 26 2021 at 14:54):

If you're trying to create or update multiple resources, you can use FHIR transaction

Lloyd McKenzie (Aug 26 2021 at 14:54):

(or batch if they're independent)

Kevin Mayfield (Aug 26 2021 at 15:02):

I think this has to be message though, every collection has is for a defined event.
Maybe what I need to do is keep MessageHeader content as small as possible.

Lloyd McKenzie (Aug 26 2021 at 15:05):

I don't understand what you mean by "for a defined event". If you're saying "please create X" or "please update X", that's the event and no need for messaging. If you're saying "Event X happened, here's some stuff, do what you feel is appropriate", then either messaging or a custom operation is necessary.