Creating your own virtual patients


Jonathan Round, Senior Lecturer in Paediatrics, St. Georges, University of London




Virtual patients (VP) potentially give students and trainees the opportunity to practise decision making in a risk free environment. However the vast number of possible choices that can be made during a patient encounter makes VP creation very challenging. This article outlines different approaches to this problem of choice and presents a simple method for creation of apparently complex VPs that any interested practitioner can undertake.


What is a Virtual Patient?


Text Box: Elements of a Virtual Patient
- clinical information
- choices to make
- consequence of choice
- user interface
In its simplest form a VP just allows the user, usually via a computer, to make a choice based on some clinical information. The user then is given feedback dependent on their choice. More complex VPs will offer more choices, and then link pages together, so that the information and choices available at any stage depend on the choices made earlier in the scenario.

Higher quality VPs have more realistic and complex choices available, and will teach the user dependent on their decisions. Such cases may also pay more attention to appearance, and link to other media beyond text information on the patient. However, students may value these elements less than the chance to experiment with decision making.


The problem of choice


If a VP is created with 3 choices at each level, within just 4 levels there have been over 100 situations which the user may have entered. Most clinical encounters will involve over 20 choices (e.g. should I ask about the immunisations, should I do a neurological examination, should I take a full blood count?) so perfectly realistic simulation becomes near impossible.


Approaches to Virtual Patient design


Four distinct approaches are recognised to deal with the problem of choice.

     The Hi-Fi approach. This spends a large amount of time, money and effort to model all of the possible choices the VP writing team can think of. Effort is then spent on linking the case to other media and on the appearance of the case. But this is very expensive. J.B McGee has estimated the cost at over $100,000 per case, making the creation of a large VP bank impossible for institutions, even collaboratively**.

     The algorithm method. Here formulae are developed that mimic physiologic processes in the body and in disease states, so that changes made by the user (typically administration of drugs or fluids) alter the output of the formulae and produce changes on the display, typically of biophysical variables. However this approach can only be used to create VPs where alterations in vital signs or biochemistry are the main elements of the case, such as anaesthesia, metabolic medicine or critical care pharmacology. Most of clinical medicine cannot be tackled in this way, as it is descriptive and history based.

     Have a linear approach. Here the problem of choice is solved by preventing the user from going down any wrong paths by immediate correction. However this is clinically unrealistic, where there are often several ways to tackle a problem mistakes are often not immediately obvious. This approach might be used for testing knowledge of a protocol, but will not engage students in the same way as more complex, multi choice VPs.

     The Lo-Fi method. Here effort is spent on creating a large, but limited number of choices. Users are allowed to make at 2-3 wrong choices before finding out their mistake. They are given the option, after making a wrong choice, making the correct choice, as long as the choice was not dangerous. The rest of this article outlines how to create such a case.


Creating a realistic virtual patient


  1. Decide on a suitable patient


Here you want a scenario that needs evaluation, ideally involving several steps, which might be in history taking, physical assessment, investigation and can go on to management steps. Examples might include a man with chest pain, a vomiting baby, a woman with post menopausal bleeding etc.


  1. Set nodes


Nodes are stages in the case that act as a gateway to the next part of the case. This is a construct to limit the exponentially expanding number of choices during the case back to one. There will typically be 3-5 nodes in a case, and they will represent the start of a stage of the patients management for instance they might be triage in A+E, completion of resuscitation, admission to the ward, cardiac catheterisation and  discharge home for a patient with a myocardial infarction.


  1. Create an ideal pathway


This does not have to be the only way through the case, but will give the number of steps that will need to be programmed. There should be 3-4 between each node. This limitation is again a device to restrict the potential number of situations between each node, as for each correct choice there will need to be some other choices, each of which will then lead onto other choices. There steps to this stage are shown in figure 1.


  1. Put interconnected, branching boxes between the nodes.


These will represent the situations that the patient goes through and the choices connecting them. It is important that they are placed in the emerging VP empty, again another device to manage the number of situations that the patient will go through in the case. You will need at least 100 pages in total to represent a reasonable VP (figure 2)


  1. Decide what the boxes represent and what choices connect them.


Here you will need to think what might be reasonable in a real situation, and use this as the basis for naming the choices. The pattern of empty boxes (stage 4) might not reflect real life, and the pattern can, to some extent be adjusted with boxes added or removed where essential. Further connection may also be made at this stage, including alternative routes through the case.


  1. Prune the case.


Dead end branches need an explanation and redirection back to the start.


  1. Name each box.


A logical and short naming system is needed. In our cases 0 starts the case, and the next stage or step is 1, then 2 etc. Each situation at each stage is assigned a letter alongside: 2a, 2b etc. Dead end explanation pages are given the suffix _e beside the page they are associated with: 4b_e for instance.


  1. Create a spreadsheet to define the VP


This is the way the case writer communicates with a technologist to describe the text at each situation, the choices and the names of the situations that selecting a particular choice will direct the user to. This part of the process is the most laborious, requiring imagination to create the narrative describing the clinical state of the patient in each situation (figure 3).


  1. Insert into a user interface


This can be done manually, creating individual html pages, for instance in Dreamweaver or even MS word, or automated using xml or using another application, such as Labyrinth (figure 4).


  1. Enrich with media


The skeleton of the case is now complete. Depending on time and resources, the VP can now be complemented with other features clinical photography, video, or sound. It can be linked to other sources of information, such as on-line course materials and relevant websites.


This approach will typically produce a case of 10 steps, containing 120-150 pages in under 10 hours for one person.


Other applications for virtual patients


The type of VP described here is most useful for students to test decision making skills, and requires a reasonable amount of knowledge before starting. It would be possible to use this case writing approach to teach students about disease presentations, and to write with a set of learning objectives in mind, linked closely into a course. VPs can also be used in assessment, particularly in later years of education, with a scoring system based on the path chosen by the candidate.




Creating realistic choices in virtual patients makes VP creation difficult. Using methods to limit the number of choices, cases that are close to real clinical encounters can be created. VPs can be used in a variety of settings, including teaching of clinical reasoning, communicating knowledge and assessment. 




Without Chara Balasubramaniam, Arnold Somasunderam, Ferhal Utku and Terry Poulton as well as the rest of the e-learning team at St. Georges these ideas would not have developed as they did.


For more information and for an example visit:




McGee JB


Jonathan Round                        Sept 2006




















Figure 1            Nodes interconnected with an ideal pathway




























Figure 2           VP defined with all potential situations and choices

page name

link to

link name










finish curry


Welcome. You have now been a paediatrician since 4 pm,

when your shift started. Its day 1 of the job, and you are

trying to remember all that stuff from the paed course.

Anyway, it wasn't too busy and now you have discovered

the mess and the takeaway menus. A Lamb Rogon Josh

has arrived and you are half way through, when the crash

bleep goes off "Paediatric arrest in A+E". What would you

 like to do?



run to A+E





call mdu


Excellent. Curry before your patients. Way to go. Just

remember, sometimes it really is an arrest, and its your

job to be there.



Assess ABC


After a quick detour into an elderly care ward, you make

it to A+E. As you are catching your breath, one of the

A+E nurses tells you that a six month old girl has been

brought in by ambulance with a 25 minute fit, and now

she's 'desatting'. She is called Shani, you are told. You

notice that she has an IV cannula - at least you don't

have to put in one of those. However she is still fitting,

shaking all limbs. What would you like to do?



Examine Shani




Take a history




Figure 3           Part of spreadsheet defing situations and choices in the VP.





Welcome. You have now been a paeditrician since 4 pm, when your shift started.


Its day 1 of the job, and you are trying to remember all that stuff from the paed course. Anyway, it wasn't too busy and now you have discovered the mess and the takeaway menus. A Lamb Rogon Josh has arrived and you are half way through, when the crash bleep goes off


"Paediatric arrest in A+E".


What would you like to do?


Finish curry       Run to A+E













Figure 4           Opening page from VP created in dreamweaver, using hyperlinks to represent choices