HL7 GELLO Update

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HL7 GELLO Update CDS TC Atlanta Wed,
9/19/07, Q3
Robert Dunlop, MD Director, Clinical
Development Craig Lucas, BSc PhD Analyst
Programmer InferMed UK 44-7291-7410 robert.dunlo
p_at_infermed.com http//www.infermed.com
Barbara McKinnon McKinnon Associates Inc. Project
Lead HL7 GELLO Virtual Medical Record (vMR)
Projects (O) 610-644-5245 (M) 484-883-6927 bmm15_at_
comcast.net
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Discussion Topics

• GELLO Status
• GELLO BNF
• GELLO Authoring Tool
• Next Steps

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GELLO Status

• 2005 GELLO passed as an HL7 ANSI standard.
• 2006 Industry outreach demonstrating the use of
• GELLO in ePrescribing Prior Authorization.
• Medical Objects, AU, GELLO Tool release.
• 2007 GELLO web discussion group established by
• Margarita Sordo, Harvard/Partners.
• InferMed continued industry outreach to
• Demonstrate use of GELLO in a Clinical Trial
  Roadmap.
• Identify pilot opportunities.
• InferMed release of GELLO Authoring Tool.

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GELLO BNF Feedback
Date Issue Organisation Raising Issue Proposed Solution
1 14 Dec 2006 Ability to use GELLO in Arden type MLMs to work around ambiguities in IF-THEN-ELSE-ENDIF constructs. Medical Objects Addition of conclude and continue statement to BNF CONCLUDE statement similar in function to final GELLO expression CONTINUE statement as a place-holder to force the parser to recognize a statement instead of an expression
2 14 Dec 2006 Concern about single string parameter for Factory methods Medical Objects Allow parameter lists for object construction
3 12 Mar 2007 Slight mismatch between OCL and GELLO, in that OCL is a pure expression language while GELLO seems to have introduced the concept of statements making it more like an imperative language. Medical Objects No specific proposal
4 12 Mar 2007 Problem with flatten() operator. Medical Objects Collection element types must be either all the same type, OR they may be recursively collections of the same type.
5 12 Mar 2007 How does a GELLO user create new user-defined classes or "model processes"? University of Nebraska
6 12 Mar 2007 "if expression" mentioned in section 5.14 of GELLO specification, but not in the BNF grammar. Stanford University
7 12 Mar 2007 Added the in keyword from OCL to help with LET expressions WebReach
8 13 Mar 2007 Need to specify exactly which model the GELLO expression conforms to. Medical Objects
9 13 Mar 2007 Compiler needs to have some specification of the data model it is working with. Stanford University
10 13 Mar 2007 GELLO is not going to operate in isolation and there are no defined methods for passing parameters in and out. Medical Objects


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GELLO BNF Feedback
Date Issue Organisation Raising Issue Proposed Solution
11 11 Jan 2007 Are unknown and null" both keywords, or simply runtime constants provided by the runtime? WebReach Keywords
12 11 Jan 2007 Unknown and Null as third Boolean value WebReach
13 11 Jan 2007 How are Collections of Collections typed, and how is that type represented in GELLO? WebReach
14 11 Jan 2007 no reference to how Enumeration types are referenced or used with GELLO. WebReach Enumeration are datatypes in UML and not part of GELLO.
15 11 Jan 2007 Why is Factory limited to a single string argument, rather than an argument list like method invocations? WebReach See 2. above
16 11 Jan 2007 Why are the assorted functions (like strcat, toupper, etc.) hard coded within the grammar and simply not implemented within the runtime as any other method invocation? WebReach Requested at first ballot. Should be reviewed.
17 11 Jan 2007 Regarding overall case sensitivity. How case sensitive is GELLO supposed to be? Is the grammar complete in this regard? WebReach To be decided
18 11 Jan 2007 As noted from the Root Symbol, GELLO seems to be (among other) a single ContextNavigationStatement. A ContextStatement is the "Context" keyword followed by ContextBody, but it allows only a single body element, and no other expressions (such as Lets or anything else). Also, there is a keyword defined later of "EndContext", but it's not referred to anywhere in the grammar. How is "EndContext" used? WebReach


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GELLO BNF

• InferMed BNF Summary Comments
• GELLO BNF, posted to http//www.hl7.org/v3ballot/h
  tml/infrastructure/gello/gello.htmBNF,
• contains many ambiguities, making it impossible
  to implement with standard compiler tools.
• Syntax is difficult to read with anything more
  complex than one or two nested levels of
  ifthenelse statements.
• GELLO provides too many ways to describe the same
  semantic concept, making it difficult for a
  novice to determine how to develop expressions.

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GELLO Syntax

• Potential Next Steps
• Schedule periodic teleconferences to set a more
  definitive course for GELLO via HL7 DSS Listserv.
• Document teleconference recommendations in
  preparation for re-balloting GELLO.
• Test draft recommendations in at least 2 real
  life pilot applications before re-balloting.

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GELLO Authoring Tool

• New GELLO Authoring Tool, developed by
• InferMed UK, will be donated for industry use.
• Preview HL7 Atlanta 9/07
• Capable of defining, encoding, and exporting
  structured GELLO Query Expressions.
• Aligned to HL7 V.3 RIM class model.

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GELLO Authoring Tool

• Tool Features Functions
• Buttons for each key word, data type, pre-defined
  value, and operator.
• Help text associated with each button.
• Drop-down lists of classifiers from HL7 RIM,
  associated with IntelliSense.
• Ability to import and save GELLO expressions.
• Color coding of key words.
• Syntax checking during authoring process and when
  expressions are saved.

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GELLO Authoring Tool

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GELLO Authoring Tool

• InferMed Next Steps
• HL7 Tools Technical Committee review.
• Post on HL7 Tools Utilities.
• Create execution engine with incorporation into
  InferMeds AREZZO workflow inference engine.
• Update tool based on
• Industry comments e-mail to gello_at_infermed.com.
• Issues uncovered in pilot testing.
• HL7 GELLO-OCL Syntax changes.
• HL7 RIM version changes.