Sam et al,
Sometimes it is beneficial to stand back and review the purpose
of EHRs, when trying to categorise content. No doubt you have done
this far more often than me, but for yet another high level perspective
here is my current view.
------------------------
Categorising EHR Content
------------------------
[ in the following discussion, the word "subject" is used. This refers
to the person who is the subject of a particular EHR. Information
contained in the EHR pertains to that subject. ]
In order to be as effective as possible, an EHR should record aspects of:
1. the subject's past, present, expected and desirable state.
2. changes in the subject's state.
3. the events and processes that led to, or might lead to, changes in
subject state.
4. risk factors that might influence subject state.
In order to do this, we must define the concepts/entities that express
state, processes and risks. Sometimes concepts are composed of other
concepts. Sometimes concepts are specialisations or generalisations
of other concepts. Sometimes concepts are relationships between two or
more other concepts.
Patient state can be represented by:-
* a set of reported symptoms.
* a set of measurements, observations, test results.
* diagnoses - classification by symptoms into known diseases/conditions.
* prognoses - expected symptoms or outcomes.
* outcomes from some past, present of future process.
* outcomes from some past event.
* body parts and accessories ( e.g. pacemaker, organ transplant,
walking frame).
Events & Processes can be represented by:-
* diagnostic tasks.
* prognostic tasks.
* treatment tasks.
* medication prescriptions.
* tests.
* the relationships with participants involved in the processes.
* accidents or events that sigificantly altered or might alter
the subject's state.
Risk factors can be:-
* environmental (e.g. adjacent to lead smelter).
* behavioural (e.g. smoking).
* genetic (e.g. familial history of cancer).
* allergic reactions that have occured to this subject.
It seems to me that openEHR's view of EHR content is still biased
towards the healthcare provider's view of the world, as if a person's
lifelong health status can be represented soley by a linear ( in time)
sequence of "actions" by healthcare providers. It should be remembered
that many of the "events" that change a subject's state
are independent of "intentional acts of health professionals".
In twenty or thirty year's time, we may be mature enough to realize
that the event "person X was made redundant from their employment today"
may have significantly greater effect on X's future health ( or the
health of a close friend/relative ), than "person X was diagnosed with
mumps today". If this is the case, then surely such events should
legitimately be recorded in an EHR?
I have problems with lumping too many things under observations, without
distinguishing between "state" and "changes to state". Consider the
following:-
A. The _observation_ "subject weighs Y kilograms" is a state recording.
B. The _observation_ "subject experienced severe pain in lower left abdomen"
is an event recording. An event causes a change of state.
C. The _action_specification_ "appendectomy" is a process recording. It
similarly causes a change of state.
In the above, openEHR places A and B in the observation category. But
from a healthcare perspectve, B is closer to C, than to A.
Someone looking back in time through an EHR might be looking for
seminal events of a certain class. Again, consider a person admitted
to an Itensive Care Unit (ICU) with first degree burns. The current
"Service-Action" view of the world emphasises the care provided at
the ICU, thus de-emphasing the important change_of_state event, namely
the burn event. The "Service-Action" view of the world portrays the
burn_event as an attribute (observation) of the emergency care act. Surely
a more appropriate approach should be to consider the emergency care act
as a consequence of the burn event. This would also allow for subsequent
trauma counselling to be related to the same event, rather than to the
ICU burns treatment _action_specification_. Consequently, I believe that
openEHR should include an _event_ archetype.
A similar argument can be mounted for representing risks in their own
right, rather than mere observations. Unfortunately, today's risks are often
tomorrow's virtues and vice versa. Yet, given today's medical knowledge,
the _observation_ "Person X smokes 50 cigarettes per day" carries
significant value beyond the care event for which the observation is
being recorded. Consequently, I believe there are good grounds for
establishing a _risk_ archetype.
--------------------------------------------------------------------
regards,
eric
--------------------------------------------------------------------
On Wed, 4 Dec 2002, Sam Heard wrote:
>
> Aniket
>
> Thanks for that.
> Thanks for your thoughts.
>
> > There are finite orders in the Medical Terminology
> > which can be classifed according to the department and
> > coded.
> > Effort such as CPT(Common procedural terminology) can
> > be extended and continued to encompass all such
> > 'action specifications'.
> > Thus the medical record can be structured broadly into
> > a.Enquiry specifications(history)
>
> We call these observations (as per Rector) - the subject is the source.
>
> > b.Examination specifications(clinical examination)
>
> We also call these observations - the clinician is the source.
>
> It is quite difficult to separate these more conclusively - a patient may
> say they are constipated and have not used their bowels for 5 days - in a
> nursing home a care attendant might notice that the patient has not used
> their bowels for 5 days. These are no different except in source and we have
> found it helpful to use the same information component.
>
> > c.Action specifications which can be further divided
> > into
> > 1.Clinical actions(Temparature,Pulse,Blood Pressure
> > etc.)
>
> As we are only concerned with the record - we can record these as
> observations - but they can be the subject of an instruction. For these
> types (having their own archetype) the specification is not so important -
> but with medication and other complex instructions it becomes very helpful
> to reuse the instruction data.
>
> > 2.Laboratory actions(All lab orders)
> These are instructions
>
> > 3.Procedure actions(OT,Cath-lab)
> These are often complex records - but for us at present are an observation
> with the ability to accept an action specification.
>
> > 4.Medication actions.
> Administration is the same as procedure - but the medication order is an
> instruction.
>
>
> Cheers,
>
>
> Sam
>
>
> > Thus the terminology can be classified and coded.
> > Based on the Clinical experiences the frequency of
> > these 'Specifications'can be varied and we amy have a
> > more or less structured Medical record.
> > Furhtermore,based on the granularity of enquiry
> > specifications we may be able to classify the results.
> > CPGs can be incorporated in these.
> > Comments
> > ANIKET
> >
> > --- Sam Heard <sam.heard at bigpond.com> wrote:
> > >
> > > Dear All
> > >
> > > In developing an ontology for health record
> > > recordings - an archetype
> > > ontology - I have come to the idea that there is a
> > > great deal of utility in
> > > the idea of an 'action specification'. This is the
> > > part of an instruction
> > > that says what to do - not when (or under what
> > > conditions) to do it.
> > >
> > > Let me give you an example:
> > >
> > > A medication order is an instruction:
> > >
> > > medication=Amoxycillin: dose=250mg: route=IV:
> > > frequency=three times daily
> > >
> > > The action specification is:
> > >
> > > medication=Amoxycillin: dose=250mg: route=IV
> > >
> > > The when part is:
> > >
> > > frequency=three times daily
> > >
> > > OR A Pap test notification instruction might
> > > consist of:
> > >
> > > Action is Pap Test & send specimen to laboratory
> > > When is two years since last pap test OR 1/1/03
> > >
> > > The important thing is that the 'action
> > > specification' can be reused in the
> > > EHR as a record of what was done. So a medication
> > > administration reuses the
> > > action specification of a medication order - and has
> > > a record of who
> > > administered it - likewise for the Pap test.
> > >
> > > There may be no need to do this at the information
> > > model level - perhaps
> > > leave it to the application. But there are some
> > > advantages - a consistent
> > > description of what is to be done and what was done
> > > using the same
> > > structure - guaranteed transformation from an
> > > instruction to recording an
> > > action.
> > >
> > > Comments?
> > >
> > > Cheers, Sam
> > > ____________________________________________
> > > Dr Sam Heard
> > > Ocean Informatics, openEHR
> > > Co-Chair, EHR-SIG, HL7
> > > Chair EHR IT-14-2, Standards Australia
> > > Hon. Senior Research Fellow, UCL, London
> > >
> > > 105 Rapid Creek Rd
> > > Rapid Creek NT 0810
> > >
> > > Ph: +61 417 838 808
> > >
> > > sam.heard at bigpond.com
> > >
> > > www.openEHR.org
> > > www.HL7.org
> > > __________________________________________
> > >
> > >
> > >
> > >
> > >
> > > ____________________________________________
> > > Dr Sam Heard
> > > Ocean Informatics, openEHR
> > > Co-Chair, EHR-SIG, HL7
> > > Chair EHR IT-14-2, Standards Australia
> > > Hon. Senior Research Fellow, UCL, London
> > >
> > > 105 Rapid Creek Rd
> > > Rapid Creek NT 0810
> > >
> > > Ph: +61 417 838 808
> > >
> > > sam.heard at bigpond.com
> > >
> > > www.openEHR.org
> > > www.HL7.org
> > > __________________________________________
> > >
> > > -
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> > > please send a message to d.lloyd at openehr.org
> >
> >
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