how to determine that a variable has PQ according to ISO 21090

Clinical (archive)
1

Dear all,

We are currently working on several archetypes and encounter difficulties in finding the right approach in the Ocean archetype editor.

For instance, a pain scale (VAS type, or numeric 0 -10). According to ISO datatypes 21090 this is a Physical Quantity.

How can this be determined in the editor? We get the option Q to set that it is a quantity. Then there is a wealth of specific units, but not a simple way of stating this is a PQ.

Am I missing the point here?

Sincerely yours,

dr. William TF Goossen
director
Results 4 Care b.v.
De Stinse 15
3823 VM Amersfoort
the Netherlands
email: Results4Care@cs.com
phone + 31654614458
fax +3133 2570169
www.results4care.nl
Dutch Chamber of Commerce number: 32133713

2

Hi William,

Have a look in CKM at

CLUSTER.Symptom-pain [Pain symptom]

Under Current Intensity ,a numeric 0-10 pain scale, is modelled as a
Count, since Pain scale has no agreed international physical units.
Count and Quantity are both sub-classes of Amount in the openEHR ref
model but for Quantity, the units attribute is mandatory (UCUM units).

I see mention of a 'standard 10cm. VAS' . In this case, it could be
modelled as a Quantity, property type Length Units cm. This element
could be included in the archetype alongside the Count element, but I
am not sure that the physical length has any particular significance
and this may just be over-complicating the model. e.g Would a
'large-print' 20cm scale with 10*2cm intervals not be equivalent?

This was an interesting find via Google -summary of pain scales

http://www.clinicalinfometrics.northwestern.edu/archive/Tab%208%20Pain%20Measures.pdf

Regards,

Ian

PS Derek Hoy tells me you will be over in Scotland in the near future.
It would be nice to meet up and say hello.

3

Hi William

I guess the point here is model what clinicians want and understand. I do not think that pain scales have any idea of ‘cms’ – so units does not seem appropriate.

If you want a real with no units, you can use ‘qualified real’ property which allows a blank unit.

Cheers, Sam

4

In a message dated 8-2-2009 4:47:16 W. Europe Standard Time, sam.heard@oceaninformatics.com writes:

Hi William

I guess the point here is model what clinicians want and understand. I do not think that pain scales have any idea of ‘cms’ – so units does not seem appropriate.

If you want a real with no units, you can use ‘qualified real’ property which allows a blank unit.

Cheers, Sam

Thank you Sam,

This is helpful. One addition to this: is the definition of real also allowing a score on the VAS of say 4.5? So decimals? Some pain scales use the numeric values 0 - 1 - 2 till 10 (the numeric score variant), but others allow setting a cross on a 10 cm line and then the actual score is determined allowing decimals.

Sincerely yours,

dr. William TF Goossen
director
Results 4 Care b.v.
De Stinse 15
3823 VM Amersfoort
the Netherlands
email: Results4Care@cs.com
phone + 31654614458
fax +3133 2570169
www.results4care.nl
Dutch Chamber of Commerce number: 32133713

5

Hi Sam,

We have tried, but it is not possible to represent a proper VAS scale in the archetype editor.

What clinicians want is exactly as I said before: being able to score a 5, 7, 10 for pain.

This looks like the above instrument in this picture.

But as you can see in some instance the patient will say, my pain today is like a 7.3 or a 3.6 or a 9.9

The qualified Real does not deal with it. So it appears not possible to handle the ISO 21090 PQ datatype which would allow to have a decimal.
Further the qualified real does not allow to set the minimum 0 and maximum 10 score.

If we apply the valid and reliable McGrath for pediatrics, we see the five level faces, where 5 is obvious the :frowning: sign (much pain) and the 1 is :slight_smile: (no pain)

This would really be an ordinal, but stored with a number. For this one the qualified real would do.

So we do experience difficulties in using the archetype editor to proper represent clinical and scientific knowledge.

Hope you can find a solution for this.

Thanks William

In a message dated 8-2-2009 4:47:16 W. Europe Standard Time, sam.heard@oceaninformatics.com writes:

Hi William

I guess the point here is model what clinicians want and understand. I do not think that pain scales have any idea of ‘cms’ – so units does not seem appropriate.

If you want a real with no units, you can use ‘qualified real’ property which allows a blank unit.

Cheers, Sam

From: openehr-clinical-bounces@openehr.org [mailto:openehr-clinical-bounces@openehr.org] On Behalf Of Williamtfgoossen@cs.com
Sent: Thursday, 5 February 2009 11:38 PM
To: openehr-clinical@openehr.org
Subject: how to determine that a variable has PQ according to ISO 21090

Dear all,

We are currently working on several archetypes and encounter difficulties in finding the right approach in the Ocean archetype editor.

For instance, a pain scale (VAS type, or numeric 0 -10). According to ISO datatypes 21090 this is a Physical Quantity.

How can this be determined in the editor? We get the option Q to set that it is a quantity. Then there is a wealth of specific units, but not a simple way of stating this is a PQ.

Am I missing the point here?

Sincerely yours,

dr. William TF Goossen
director
Results 4 Care b.v.
De Stinse 15
3823 VM Amersfoort
the Netherlands
email: Results4Care@cs.com
phone + 31654614458
fax +3133 2570169
www.results4care.nl
Dutch Chamber of Commerce number: 32133713

Sincerely yours,

dr. William TF Goossen
director
Results 4 Care b.v.
De Stinse 15
3823 VM Amersfoort
the Netherlands
emails:
Results4Care@cs.com
williamtfgoossen@cs.com
info@results4care.nl

phone + 31654614458
fax +3133 2570169
www.results4care.nl
Dutch Chamber of Commerce number: 32133713

6

Hi William

I am not sure of the requirements but I think you want a real number between 0 and 10.

You are right that there is a bug in Qualified Real that does not allow you to set a max and min value (this has been added to Jira).

The most correct way to deal with this is as a proportion (on the grounds that a real number on its own in medicine is a ratio or proportion of some kind). This needs to be unitary (ie denominator of 1). The ADL looks like:

ELEMENT[at0005] occurrences matches {0..1} matches { – Pain

value matches {

DV_PROPORTION matches {

numerator matches {|0.0..10.0|}

type matches {1}

}

}

}

Hope this is helpful and thanks for finding the problem with the qualified real.

Cheers, Sam

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