Name: Shilpashree Srinivasamurthy

Subject: ACS 560 Software Engineering

Paper 3: A UML Approach to Process Modelling of Clinical Practice Guidelines for Enactment

Advisor: Dr. John Tanik

Date: 10/22/2010

This paper analyses the use of UML process modeling techniques for guideline representation and proposes the automated generation of executable guidelines using XMI.Clinical Practice Guidelines (CPGs) contain clinical knowledge that is used to ensure and improve quality of healthcare, to reduce inappropriate variations in clinical practice and healthcare costs, used for medical education, alerts and reminders, case management and decision support.This paper describes research into the use of UML to represent guidelines for enactment in a WfMS (Workflow Management System) environment. The different stages in modeling enactable CPGs are shown in figure 1. The paper only concentrates on first phase shown in the figure i.e, transformation of plain English to UML notation.

Figure 1: Different stages in modeling enactable CPGs

The paper initially describes the modeling formalisms of CPGs. The models for representing CPG had primitives for representing:

  • Decisions: They select, automatically or through user interaction, from a set of alternatives
  • Actions: They can be clinical interventions, data collections and wait states recommended by the guideline
  • Patientstates: These states describe the state of a patient as a result of an intervention or decision
  • Execution states: These states describe the status of the guideline process and its actions

The next section describes about the UML for process modeling. Process modeling in UML is supported through activity diagrams. Figure 2 shows the activity diagram for a clinical process. To enact a process, a WfMS should know which activity should be called next and what data the activity needs. The internal structure of data objects is described in class diagrams. Figure 3 shows a sample class diagram of patient data model. The TestResult class containing test name and test result attributes is a specialization of Patient class containing Patient ID.

Figure 2: Activity Diagram for a Clinical Process Figure 3: Class diagram showing workflow

The next section explains how CPGs may be modeled using UML. The following table shows the mapping between CPG and UML elements.

CPG / UML
Action Step / Activity
Case Step / Decision point
Choice Step / Activity followed by a decision point
Patient state / State
Start- and stop state
Pre- and post condition

UML supports stereotyping through its extension mechanism which allows the graphical notation to be tailored for clinicians by introducing easy to understandelements that map to complex combinations of UML elements.

The next section explains a case study of a CPG on diabetes mellitus.

The following section explains about automating the UML guideline. The following steps need to be done to automate a UML guideline:

  1. Export UML to XMI
  2. Convert XMI to workflow rules using a converter

Advantages of UML:

  1. Vendor independence
  2. Benefits from further innovative developments of the used technologies
  3. Standardized technologies make guidelines shareable when using the same technology