PIX/PDQ V3 - Discussion

TCON March 29, 2007

Attendance - Bill Majurski (NIST), Mike Nusbaum (ITI Planning Co-Chair), Sandra (IBM), YongJian (GE), Laurie Williams (IBM), Vassil (EPIC), Karen Witting (IBM), Lynn F (HIMSS), Jeff Romaposki (Accua technologies), charles Filson (Accua technologies), Roberto (MIcrosoft), Rita (IHE Canada), Mike Henderson (Eastern Informatics)

Topics

• Mesa tools from INFOWAY/Rita
• What needs to be decided regarding the profile? Added to profile? Collect issues to organize future work.

Major issues

1. In the Supplement, the only schema published was for Patient Update
2. The HL7/V3 messages specified are outdated
3. Need Web Services specification to support
4. Decide on requirements for V2 vs V3 support in an implementation
5. Solve Patient vs Person debate - Existing message is based on Person, Europe prefers Patient

Open Issues/Action Items

1. Description of issue: Relation of v2 to v3 - Vassil
2. Analyze v2/v3 use cases - Vassil
3. Rita will send notes to Vassil
4. How to manage supplement given evolution of HL7 specifications? How to track HL7 changes when we have normative but incomplete parts of HL7 spec and the incomplete parts that will evolve? We need a set of core principles that allows us to track HL7 work. - Vassil
5. Next call scheduled for April 17, 11:30 - 1 Central

V2/V3 support opinions

A proposal was put forth to keep v2 and v3 separate with no linkage. Implementers and communities should choose the protocol they need/want. Some of the more detail ideas presented were:

Vassil approach - v2 required for intra-enterprise, v3 for inter-enterprise
Roberto - v3 is of interest only in many places
Rita - new thinking in Radiology - new adopters not doing old approach
Vassil - ITI is different because it has two types of customers - other domains and communities
Roberto - Take Ethernet etc. approach. Consider V3 as a new profile. Keep separate. Allow vendors and communities to select.
General - This is only a volume 1 issue. No impact on volume 2.

Patient vs Person

Supplement uses New Person Added message. Feedback from Europe, please use patient related message instead, a possibility is Patient Activate. Initiate was not represented on the call. They probably have strong opinions. Need feedback from INFOWAY. There are differences between 2006 and current ballot on Patient topic in HL7. Are we aiming a moving target?

Schemas

Test tools include full set of schemas and sample example messages. Create structure for schemas: have front end (source forge example) have intermediary, select download location don't have direct url don't publish direct link to schemas to deter operational use introduce zip or other indirection Include live link in PDF to a stable location

Web Services/WSDL

WSDL will be last part of supplement developed to allow harmonization with other WS efforts (profiles and white papers) and XDS. The goal is consistently structured WSDL, WSDL namespaces, and naming conventions.

Issues resulting from test tool development by Rita

Supplement text needs various corrections...

1. Align business logic between v2 and v3. Example: Pix consumer queries Pix manager to match specific patient id, different use cases are discussed. V3 volume 1 material focuses on how v3 is different. Does not mirror structure of v2. But, approach was to have v3 offer the same use cases as v2. Rita had to make the decision to implement much of what is in V2. Profile should be more clear.
2. Align data models between supplement with a specific HL7 version (one has to be chosen). Differences: labels for concepts, required/optional status of individual pieces. Models in supplement are a subset of HL7 models (on purpose). Supplement tables are less constraining than HMDs. Renaming of elements in the RIM will propagate to us. During test development, Rita used HL7 distribution CD as reference. Differences exist between CD and online version.
3. Technical details on how to do things between supplement and model. Patient merge example. IHE approach and HL7 approach different. An example is the Notification transaction in the supplement. When patient info updated, PIX MGR sends notification message.
   • Supplement mechanism is incompatible with HL7 schemas
     • in IHE vocabulary maps to HL7 message with everything optional
     • in HL7 there are things that are required.

May be editing problem or text cleanup needed in supplement. Decisions were made during development of test kit. Followed HL7 while keeping spirit of supplement.