Dr Paul Miller: May 06, 2019
In my last blog I promised I would start to provide a guide to openEHR for health and social care practitioners. This to encourage people to become involved in helping to define and agree the content models that we will use on the National Digital Platform. These models are very important as they will be utilised by the applications that people will use every day to help look after our patients and clients.
A model is just a representation of something else. An architect’s drawings are models of buildings, and an engineer’s designs are models of a new plane. In our case we are creating computer representations of clinical ideas like blood pressures or prescriptions – these are also just models.
Clinicians in medicine are familiar with models as we use them everyday – models of disease, models of pharmacology and physiology. All these things are real world phenomena that we have turned into descriptions and flow charts and diagrams so we can better understand how people work, why they become unwell and what we can do to help.
OpenEHR has two types of models that together are used to describe clinical concepts in ways that computers can understand. These are called ‘Archetypes’ and ‘Templates’. Archetypes are the ‘kitchen sink’ models – the ones that contain definitions for everything that anyone would ever want to record about a concept.
Templates are models for using in applications – they use parts or ‘elements’ from archetypes in combination to create content for use by different people and in different settings. What a GP wants from a blood pressure record is different from an anaesthetist in an operating theatre. Blood pressure is the concept represented by the archetype, but the two different users want and need different views. These are represented as templates.
The UK Resuscitation Council has a new process for agreeing personalised recommendations for a person’s clinical care in a future emergency. This is called “ReSPECT”, an acronym for “Recommended Summary Plan for Emergency Care and Treatment”, and the agreement includes critical information such as resuscitation wishes.
The process results in the completion of a purple form and this form is (a bit like the red DNACPR forms it intends to replace) meant to stay with the patient.
The challenge as always with this type of anticipatory care plan is to ensure that the information is accessible when necessary and can be contributed to by all the people permitted to do so. This is impossible to do reliably with a paper form, so one of the first things we are doing in NDS is bringing support for the ReSPECT process onto the National Digital Platform. You can read more about this in our previous blog.
To do that, we need to create a model of the ReSPECT form in openEHR. The model is a ‘Template’ that uses elements of different ‘Archetypes’.
Here is section 2 of the ReSPECT form:
In the paper world, an author would write down a brief summary of the relevant information. However, on computers, users usually like some of this information to be a bit more structured, and maybe even to be filled in using existing data. If the patient already has a ‘diagnosis list’ data from there could be used in the form.
Our model of this part of the ReSPECT form will need a place to add or display ‘diagnosis’. This might just be text, or it could a terminology description from Read Codes or SNOMED CT. openEHR already has an Archetype for this purpose, called ‘Problem/Diagnosis’. You can view it on our Clinical Knowledge Manager (CKM) here, and if you click on the ‘data’ tab you can see all the available elements for this archetype. Here is how it looks on CKM:
Above, I have highlighted the two elements we decided to use in the ReSPECT template, and you can view the ReSPECT template itself here.
Below, I have highlighted where the two elements from the Problem/Diagnosis archetype are positioned in the ReSPECT template:
For our purposes, we have changed the label for the ‘Problem/Diagnosis name’ as shown in the Archetype to ‘Key diagnosis’ for use in the template, but the data definition remains the same.
This same approach of selecting the required elements from the archetypes for the template is applied many times to build the content of the ReSPECT template and represent the data that underpins the form.
This approach becomes really powerful for complex and clinically critical data, such as CPR Decisions. Here is the CPR section in the ReSPECT form:
In the ReSPECT template, we use the highlighted parts of a “CPR Decision” archetype as shown below:
Below is how this looks in the ReSPECT template:
Once we have this data recorded on the digital platform it can then be re-used in other templates for different use cases. For example, a template using the element ‘CPR Decision’ alone could be used in an application for emergency workers to display the information in a format that makes it quick and easy to understand in pressured environments. The critical thing is that the data is the same regardless of which template it is included in or how it is used in applications.
This provides us a ‘store once, use often’ ability that we have not had before in NHS Scotland at any scale, though often aspired to. It crucially also provides us with a reliable source for the “true” record, as Steve was discussing in his last blog post. This makes a huge amount of sense because having multiple records in different systems all of which are trying to say the same thing just does not work, and for risky information like resuscitation wishes rapidly becomes unsafe.
I hope this provides you with a useful introduction to how archetypes and templates work to create clinical content in openEHR. You do not need to know much more than this to begin contributing to model reviews, and you could possibly get away without even knowing this, although it will definitely help!
Content reviews are managed in CKM by editors, with reviewers who can ‘adopt’ archetypes and templates to keep informed about changes, review rounds and other information. You can create a login and account on CKM now, and then ‘adopt’ the ReSPECT template and any other models you may have an interest in.
Finding your way around CKM can be a little confusing at first, so in future posts I will provide some help with that. There is some guidance available from SCIMP and, although it refers to a previous version of CKM, you may still find it useful.
At NDS, clinicians are leading on the development of these models. Over the coming months we will train and support more people from clinical and social care backgrounds to become editors, authors and reviewers of NHS Scotland’s archetypes and templates.
Dr Paul Miller, Clinical Lead - NDS