Conceptual Knowledge Architecture

A majority of content on this page is excerpted from the HL7 FHIR Clinical Guidelines IG, with some generalizations to be applicable for describing both OMG BPM+ and HL7 CPG-on-FHIR standards. Credit to the authors of that specification for describing this Clinical Practice Guidelines (CPG) knowledge architecture. Components of this architecture are, or will be, referenced in other parts of this Care Management project. In particular, refer to the COVID-19 Severity Classification and Disposition use case and the discussion on Transforming BPM+ Models to CPG-on-FHIR that is based on the COVID-19 use case and aligned with this knowledge architecture.

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Workflow

The HL7 FHIR Clinical Guidelines IG explicitly does not address, local workflows due to their significant variation, complexity, and need for consideration for local factors (e.g., specific resources and resource type, policies, customized or localized tooling), as well as to avoid conflating detailed clinical workflow descriptions/definitions with the flow of abstract clinical activities often necessary to describe as part of the care process in guideline recommendations.

Future updates to this knowledge architecture will expand to include more explicit guidance on use of clinical / organizational workflows, a primary focus for OMG BPMN standards. When applying the CPG Knowledge Architecture, BPMN (process model definitions) may be used as an alternative to CMMN (case model definitions) to represent decision flow or decision orchestration within clinical pathways, most closely aligned with a pathway Strategy in this architecture. However, this use of BPMN decision flow should be distinct from order management workflows that are often dependent on organizational policies and EHR system vendor platform integration.

Pathway Definition

Recommendations

Recommendations are the formalization of a singular narrative guideline recommendation that make explicit the clinical activity to be taken or not to be taken. The Recommendations formalize the decision logic or applicability logic to be applied to the requisite set of data elements (Case Features) in order to instantiate the proposed clinical activity resulting in a patient specific recommendation (Proposal).

Strategies

Strategies are approaches for combining, orchestrating, or associating related guideline recommendations and typically scope to a particular concern addressed within the guideline. Strategies may be longitudinal, require temporal orchestration, and reuse or repurpose data elements (Case Features) and other components (e.g., the attributes and status of requests and events) of the Recommendations it scopes.

Pathways

Pathways convey the full scope of guideline recommendations in a manner that can be implemented for the purpose of guiding patient care within a singular CPG. In part, pathways serve a similar yet higher order function as strategies, and serve the function of addressing interdependencies such as decision and orchestration logic across multiple concerns.

NOTE: the knowledge engineer MUST pay special attention to the separation of decision logic about what to do for the patient (e.g. in a recommendation) from description or inferencing logic that describes something about or the nature of the patient (e.g. clinical pathological process, risk, severity, in qualifiers thereof). This greatly simplifies the decision logic as well as makes the inferences about the patient readily available for other logic and/or use cases. This takes particular attention from the knowledge engineer and is critical for this implementation guide.

The slide below is copied from Davide Sottara’s presentation during the OMG BPM+ Health workshop in Sept 2020. The point to highlight here is the conscious separation of DMN (Strategy) knowledge from DMN (Inference) knowledge, which aligns with this knowledge architecture. Strategy knowledge is a component of the Pathway Definition as a means to organize and orchestrate recommendations, whereas the Inference knowledge is included in this architecture as “Derived features” in the Case Summary layer of this architecture. The Case Model, or BPMN Model, are included here as representation of the decision flow and orchestration knowledge in the pathway. This same separation of concerns is revisited in description of Transforming BPM+ Models to CPG-on-FHIR.

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Care Plan

A Care Plan can be conceptualized as the patient-specific or instantiated “Plan” concretized against an individual Case. The Care Plan describes the intention of how one or more healthcare professionals intend to provide care for a specific patient, group, or community for a period of time, possibly limited to care for a specific condition or set of conditions. In the CPG, the care plan is scoped to the condition(s), intervention(s), recommendation(s), and other relevant “plan” content in this limited context (e.g., contraindications, correlated orders and results such as drug levels, or other orders or fulfillments that must be considered in triggering, decision, or orchestration logic).

A patient-specific recommendation, that has taken into account all the criteria in the computable decision logic and affords the ability for a care team member to make a request (order, prescription, schedule) is known as a proposal. Such a Request (see FHIR Request pattern) may be being considered for a plan, planned, proposed, requested, or performed within a clinical information system mediated workflow. “Performed” requests have reached a state of completion resulting in an event (see FHIR Event pattern). Proposals carry sufficient information to initiate a request.

Case Features

The features of the case are the clinically meaningful data elements that describe the current and relevant past state of the patient that is pertinent to the scope of the guideline recommendations and related decisions to be considered. These typically describe the clinicopathophysiology pertaining to the condition(s) and state of disease, potential intervention(s), and contraindications related to guideline recommendations. These may include patient presentation (e.g., symptoms), clinical assessments and observations (e.g., physical findings, labs, vitals, diagnostic results, -omic profiles), diagnoses (e.g., problems or conditions) including temporally related risk and severity scores, exposures (e.g., current and prior interventions such as medications/substances and procedures), and other information that may be relevant to the scope of the guideline.