This project leverages the ongoing effort from the IPS project which has an established content and data model informed by FprEN 17269:2019 from CEN/TC 251 which uses both the HL7® CDA and HL7® FHIR® standards.
However, the PS-CA Use Cases and the implementation ecosystem are not identical to IPS. For example, the PS-CA specification has to account for jurisdictional differences in the following: system capabilities, established charting practices, and change management capacity. Notably, the PS-CA also has to account for creation of Canadian patient summaries through provider-generated summaries (as a result of an encounter to provide a snapshot of the patient's health care), as well as machine-generated summaries (created automatically by provincial electronic health records).
As a result, the PS-CA has applied a slightly different approach in implementing the data model from the original IPS project. While the elements within the IPS data model remain the same, the expectations for when and how the elements are implemented require a more nuanced approach.
The Pan-Canadian Patient Summary project leverages an iterative, consensus-driven, version-based approach for publishing specification content. For more information on the development process and roadmap, implementers are encouraged to review PS-CA Specification Preface.
Alignment with the International Patient Summary Global Specification (IPS-UV)
The PS-CA FHIR profile set will be as closely aligned to the HL7 IPS-UV specification as possible in order to allow vendors in Canada to implement patient summaries aligned with local needs. This means that every effort will be made to adopt the international specification and analyze its constraints with practical implementations in mind.
The PS-CA specification attempts to profile in a way that allows the patient summaries (instances) to be conformant to the IPS-UV specification without having to formally derive from the profiles.
What this means is that instances should be able to conform to the IPS-UV specification even if the generating implementation does not fully meet the IPS-UV expectations for being able to generate all optional slices, demonstrate support of all Must Support elements, etc.
In places where profiling of the PS-CA uncovers challenges with the IPS-UV (e.g., IPS-UV incorrectly applies slicing or applies Must Support flags to elements not utilized in Canadian workflows) these challenges are noted and brought forth to the IPS FHIR team through formal change request mechanisms.
Differences between the IPS-UV and PS-CA
Differences between the IPS-UV STU1 and PS-CA are largely limited to areas where further localization was required as well as areas where the PS-CA needed to relax system conformance expectations in the first version to align to "current state" jurisdictional capabilities.
Differences between this IPS-UV STU 1 profiles and the PS-CA profiles are noted on the respective profiles pages.
Domain Prioritization Differences
Jurisdictional prioritization of certain domains over others in the initial trial implementation is also a driver of differences between the two specifications.
Given the aggressive timelines of the first phase of the Patient Summary project, and input from detailed consultation with participating jurisdictions, a national FHIR profile set that covers a subset of data domains was recommended for PS-CA version 1.0. PS-CA profiles were developed for this subset with the intent of developing the remaining PS-CA profiles in a later release.
This staggered approach has had a significant impact on how constraints are applied to the sections of the PS-CA Composition resource. Notably, IPS-UV applies Must Support flags to all its sections, whereas the PS-CA has only applied Must Support flags to the header section and recommended sections (Medication Summary, Allergies & Intolerances, Problem List, Immunization, History of Procedures) noted in the diagram below.
In order to maintain compliance with the IPS-UV, the PS-CA Composition has maintained the required cardinality on Medication Summary, Allergies & Intolerances, and Problem List sections. However, it provides clear guidance to implementers for what should be included within the
section.entry element if:
- for a given patient, no information exists for that section, or
- the implementing system can not produce the section (due to lack of capability, jurisdictional restrictions, etc.).