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  1. Clinical templates, registries and terminologies Angelo Rossi Mori National Research Council, Rome - Italy HL7 / Clinical Templates SIG & CEN / TC251 / WG II

  2. Contents • what is a clinical template ? batteries, data sets, reusable fragments of messages • 3 pillars for semantic interoperability repositories, templates, value domains • “HL7 light”: a complementary approach • decentralisation of a registration process • involvement of professionals and agencies • a common strategy for HL7 and CEN ?

  3. what is a template ? too many legitimate perspectives and options

  4. battery in HL7 1/5 • “battery: • a set of one or more observations • identified as by a single name and code number, • and treated as a shorthand unit • for ordering or retrieving results • of the constituent observations. … • Vital signs, electrolytes, routine admission tests, and obstetrical ultrasound are all examples.”

  5. battery in HL7 2/5 • "Vital signs (conventionally) consist of • diastolic and systolic blood pressure, • pulse, and respiratory rate. • Electrolytes usually consist of • Na+, K+, Cl-, and HCO3-. • Routine admission tests might contain • CBC, Electrolytes, SMA12, and Urinalysis. • (Note that the elements of a battery for our purposes may also be batteries). "

  6. battery in HL7 3/5 • "Obstetrical ultrasound is a battery • made up of • traditional component measurements • and the impression, • all of which would be returned • as separate results • when returned to the requestor. "

  7. battery in HL7 4/5 • "A test involving waveform recording • (such as an EKG) • can be represented as a battery made up of • results of many categories, • including • digital waveform data, • labels and annotations to the data, • measurements, • and the impression. "

  8. battery in HL7 5/5 • "The word battery is used in this specification • synonymously with the words profile or panel. • The individual observation elements • within a battery may be • characteristic of a physiologic system • (e.g., liver function tests), • or many different physiologic systems.”

  9. Crucial issues • Version 2.x provides no rules for harmonization / registration of batteries • Constituent elements of a batterymust be predefined • Need for a registry of data elements • Need for computable value domains(numeric ranges, code sets)

  10. Example on Lab Data results • [from HL7 version 2, § 7.4.3] • OBR|1|870930010^OE|CM3562^LAB| 80004^ELECTROLYTES|… • OBX|1|ST|84295^NA||150|mmol/l|136-148|... • OBX|2|ST|84132^K+||4.5|mmol/l|3.5-5|... • OBX|3|ST|82435^CL||102|mmol/l|94-105|... • OBX|4|ST|82374^CO2||27|mmol/l|24-31|…

  11. Option 1: master tables • the content of the "electrolytes“ template • is a set of 4 OBXs • with locally predefined names and units. • For example, stored in Master Tables • Only the template name is sent in the order • Numeric values • will be filled in at the instantiation • How can we harmonize definitions • across master tables of different organizations ?

  12. negotiating the template • the master table approach involves • a negotiation between sender and receiver • they exchange the definition of template, • they refine it • - how to assure version identification ? • - is it safe to send only the template name in an order, without the detail on content ?

  13. NEW: panel names in LOINC • [from LOINC, vers. June 2000, at www.regenstrief.org/loinc] • hemogram panel(code=24358-4) • panel elements = “erythrocytes; leukocytes; hematocrit; hemoglobin; MCV; MCH; MCHC; RDW” • hemogram & platelets panel (code=24317-0) • panel elements = “hemogram panel; platelets; MPV”

  14. option 2: LOINC+ as register • first 51 panels are available • fast and reactive maintenance process • LOINC could be a good source for names and codes of templates • but description of content is text-based, i.e. • ranges are not computer-processable • value sets do not use LOINC codes • is the description “defining” the template ? • which change justifies a new template ?

  15. Example on Medical Recordin HL7 • [from HL7 version 2, § 9.6] • TXA|0001|HP^history & physical|TX^text| … • OBX|1|CE|2000.40^CHIEF COMPLAINT|| ... • OBX|2|ST|2000.01^SOURCE||PATIENT ... • OBX|3|TX|2000.02^PRESENT ILLNESS| |SUDDEN ONSET OF CHEST PAIN. 2 DAYS, PTA ASSOCIATED WITH NAUSEA, VOMITING & SOB. NO RELIEF WITH ANTACIDS …

  16. option 3: set of detailed standards • CHIEF COMPLAINT • SOURCE • PRESENT ILLNESS • … how to obtain wide consensus • on section of documents ? • see standardization initiatives in • ASTM 31.25 and • Clinical Doc. Architecture level 2 (PRA)

  17. Systematic rules for composition • Template: “systolic blood pressure” • OBX for systolic BP • qualifiers: • patient's position • device • measurement site • the circumstances of the measurement could be: • additional OBXs • coded elements in a compositional data type • detail within a “molecular code”

  18. option 4: combinatorial codes • the observation code for systolic BP can be either • a single “molecular code” or a combination of codes on • patient's position • device • measurement site • We must control the overlap between • terminological component of observation code • explicit RIM attributes • (rules for combinatorial codes • are managed by coding system developers)

  19. recurring subsegments • [from ENV 12610, Medicinal product identification, • Table 5.2.2 : Trade medicinal product identifiers] • clinical template: • trade trade unique • contents: group name trade ID • 4.2.1 medicinal product • designation x x x • 4.2.8 dosage form x x • 4.2.14 route of administration x x • 4.2.6 strength x x • 4.2.11 medicinal product • batch number x

  20. option 5: RMIM - CMET • define new (local) templates • applying the same development methodology • conceived for standard messages in HL7 • need for thousands of data elements • as (local) extensions of the RIM • need for a registry of templates ?

  21. Schemas (e.g. BizTalk) • [from the iEHR schema, by iSoft, at www.biztalk.org] • <ElementType name="QuantifiableObs” … > • <element type="MeasurableQuantity"/> • <element type="ResultAsNumber"/> • <element type="ResultAsRange"/> • <element type="ResultAsDate"/> • <element type="ResultAsText"/> • <element type="ReferenceLimit"/> • </ElementType>

  22. option 6: XML family • define XML labels • define their combination by measures “external” to HL7 constructs (e.g. XML schemas ?) • in Biztalk (not limited to healthcare): • meaning of labels and value sets are not described ! • no comparison of XML tags from different vendors ! • in ebXML (not limited to healthcare) : • registries ? • a specific HL7 registry with XML.org ?

  23. Conditional templates 1/3 • [from the CDC form for Hepatitis A notification] • BASIS FOR DIAGNOSIS • CLINICAL DATA • Symptomatic ? yesno unknown • if yes, Onset date ____ • Diarrhea yes no • if yes,from ____ to ____ • Jaundiced yes no • Hospitalized yes no • Died yes no • LABORATORY TESTS ...

  24. Conditional templates 2/3 • Diarrhea yes no if yes,from ___ to ___ • Diarrhea is a finding, with boolean values. • The above structure could be generalised as: • Template: “boolean finding with dates” • booleanFinding^LOINC^code | booleanValue • if booleanValue = “yes” • “starting date”^LOINC^2345-7 | date • “ending date”^LOINC^3456-8 | date

  25. Conditional templates 3/3 • Template: “boolean finding with dates” • booleanFinding^LOINC^code | booleanValue • if booleanValue = ... • Refinement of template: • conditional block: “diarrhea with dates” • “diarrhea”^LOINC^1234-6 | booleanValue • if booleanValue = “yes” • “starting date”^LOINC^2345-7 | date • “ending date”^LOINC^3456-8 | date

  26. option 7: Arden syntax • Arden syntax is the existing mechanism • for if-then rules • it is harmonized with RIM and HDF • it could be extended for this purpose • (a special mechanism • just for this kind of template …)

  27. Clinical check list ? (… DICOM ) • [from “Nomenclature of Digestive Endoscopy”, OMED 1994] • template name: “description of duodenoscopy” • data elements value domain (for duodenoscopy) • lumen {normal, spasm, stenosis, …} • contents {blood, biliary stones, parasites, …} • wall {rigid, decreased distensibility, …} • mucosa {atrophic, granular, hyperemic, …} • hemorrhage {mucosal bleeding, varices, …} • flat lesions {aphta, infiltration, …} • protrusions {papule, polyp, …} • … ...

  28. Legal data sets ? • [from the Belgian law of 14.08.1987] • template name: “data items for nursing file” • data elements • Care of hygiene • Care of mobility • Care of elimination • Care of food • Food by probe • Specific care of the mouth • Handling emotional problem • Care for disorientated patient • ... Vital parameter registration Physical parameter registration Surveillance of tractions, plasters Withdrawal of blood Administration of medications Surveillance of drips Care for closed wound Care for open wound

  29. option 8: Z segments • Where is the limit ? • Why clinical templates cannot extend to whole messages and Z-segments ? • Registration and harmonisation • = appropriate control by HL7 • over the Z-segments • (and over the list of allowed data elements) • large benefits to the whole HL7 community

  30. why templates ? purposes and use cases

  31. typology of templates 1/2 • USAM tables • e.g. role-link-role • ENCAPSULATION (terminology vs RIM) • e.g. to describe style in messages • BATTERY = set of “Acts” • sets of observations (i.e. battery) (precise description for orders and payments) • goals, outcomes • sets of procedures (e.g. clinical guidelines) • data sets (e.g. from regulatory agencies)

  32. typology of templates 2/2 • CDA-L2 = set of sections • Clinical Document Architecture - level 2 • expected shape of a document • DICOM SR = set of sections, acts, materials, devices, … • MESSAGES = profiles, new messages ? • internal needs of an organization • needs of a specialty (e.g. cancer network) • needs of agencies (e.g. Public Health reporting) • needs of a region / country (e.g. xDT Germany)

  33. Expressing constraints on the RIM • [from Usam manual, version 2.6, May 2000 (table 17) ] • template: “action with admitted relationships” • action • has precondition • precondition in criteria mood • has trigger • trigger in criteria mood • has contraindication • contraindication • …

  34. Style guidelines • a) Representation using “Value” Name style: • name is generic, values are elements of a list • HLA Antigen found = {Aw43, B27, Cw1, Dw12, ...} • b) Representation using “Variable” Name style: • list of all names, values are boolean • HLA Aw43 Antigen = {Present, Absent} • HLA B27 Antigen = {Present, Absent} • … • Both styles are in use: which one should be preferred ? • clinical templates = guidelines for style ?

  35. guidelines of practice • define local or common practice rules • [example from HL7 v2.x] • “Routine admission tests might contain • CBC, • Electrolytes • SMA12 • Urinalysis • (Note that the elements of a battery for our purposes may also be batteries).”

  36. NO - automatic filling in of defaults • [from “The Berkshire Eagle”, May 23, 2000] • template: “normal liver” • A GP was discovered to use “templates” • for the most frequent “normal situations” , • to automatically fill in • a list of detailed default values • as if he was actually making • each individual observation • this is not our meaning of clinical template

  37. cluster in ENV 13606 • CLUSTER: "original component complex • used to aggregate data items and/or other clusters • to represent a compound concept. • EXAMPLES. • A blood pressure measurement consisting of systolic and diastolic pressure, • a collection or closely related clinical findings, • results of a battery of laboratory investigations, • a treatment schedule consisting of several • individually specified preparations or dosages.” • (cont.)

  38. cluster in ENV 13606 • a set of closely inter-related symptoms • (e.g. a cough productive of discoloured sputum and blood); • a single act of physical examination • which generates more than one value • (e.g. heart sounds, a blood pressure taken lying and standing); • a set of quantities constituting a single test • (e.g. a differential white cell count); • a set of entries that might often be represented in a table • (e.g. auditory evoked potentials); • a single healthcare action • that had two or more purposes or consequences.

  39. weak vs strong templates • weak templates (organisers) • to organize information • e.g.subsections of a clinical document • see also headed sections • in ENV 13606 (EHCR - healthcare record) • strong templates (bundles) • to handle reusable aggregations • e.g set of structured data elements • see also clusters in ENV 13606

  40. organisers • Organisers are defined by their name only. • They contain at least one organiser or one textual data element (and bundles) • Organisers provide a weak context to their content.They provoke expectations in the human users.They convey author’s perspective on data. • The expected content of an organiser (e.g. the internal structure of a document)may be predefined to guide users

  41. bundles • Bundles are defined by their content.They identify a set of closely related items • with a ”bottom-up” process.They represent complex conceptual units. • They contain only bundles and/or ”structured” data elements (i.e. coded or quantitative data elements). • Bundles provide a strong context to their content.They set a scope for their components. • Clusters are usually predefined.

  42. bundle organiser structured item name range textual item name text quantitative item name interval with units coded item name value domain

  43. sharing templates need for registries ?

  44. emerging needs in HL7 ? • refine standard messages and documents with “local” detailed constraints or refinements, e.g. to satisfy the needs of • sub-communities (diabetes, cancer, ESRD) • ad-hoc information flows (e.g. CDC, HCFA) • regional or national information flows • management of pathology networks • registries, clinical trials, sharing records • secondary uses • reporting to authorities, statistics

  45. clinical templates: a real need ? • is there a need to reduce combinatorial alternatives and impose a common “style” ? • what is better achieved by • a-posteriori transformations ? • is there a need for control over the processthrough registration and support databases ? • (i.e. decentralise but avoid the chaos) • if communication is local, why HL7 should • introduce international rules or registries ?

  46. my vision: need for registries • if we want to share clinical templates • across organizations, • components of templates must be registered. • all names and labels used in templates • should be stored in a registry • should be mapped to the RIM classes • should have a well defined “value set” • (how can we decentralize the register ?)

  47. 3 pillars for real interoperability • The optimal strategy is based on 3 pillars: • 1. data dictionaries and metadata registries, • including appropriate “LOINC codes” • 2. clinical templates • 3. tables with enumerated value domains • they are complementary • all 3 pillars are needed to assure a real semantic interoperability

  48. 1. Metadata registries 1/2 • A registry of data elements, between • one thousand robust data elements i.e. the attributes in the RIM • millions of user-created XML labels • Specializations of the RIM: • each data element should be explicitly • registered as a child/refinement of a RIM class, • under control of the respective HL7-TC

  49. 1. Metadata registries 2/2 • Quick solution: • Collection of data sets and lists of XML tags • with either answer-list or ranges of values • (e.g. see “names for observations” in LOINC; • see also xDT/Germany, ASTM E1384) • Optimal solution: • Integrated repository (e.g. ISO 11179) • with uniform and comparative representation • of data elements from all the sources

  50. 2. Clinical templates • to aggregate data elements from the repository • (including the RIM) into meaningful fragments • i.e. building blocks, from predefined data elements, • to produce more detailed messages, between • hundreds of balloted standard messages • millions of user-created DTD/schemas • Templates (and the related data elements) • need a process for (local) registration • under the control of HL7 TCs • a neutral language to represent templates ?