An iconic language for the graphical representation of medical concepts

Background Many medication errors are encountered in drug prescriptions, which would not occur if practitioners could remember the drug properties. They can refer to drug monographs to find these properties, however drug monographs are long and tedious to read during consultation. We propose a two-step approach for facilitating access to drug monographs. The first step, presented here, is the design of a graphical language, called VCM. Methods The VCM graphical language was designed using a small number of graphical primitives and combinatory rules. VCM was evaluated over 11 volunteer general practitioners to assess if the language is easy to learn, to understand and to use. Evaluators were asked to register their VCM training time, to indicate the meaning of VCM icons and sentences, and to answer clinical questions related to randomly generated drug monograph-like documents, supplied in text or VCM format. Results VCM can represent the various signs, diseases, physiological states, life habits, drugs and tests described in drug monographs. Grammatical rules make it possible to generate many icons by combining a small number of primitives and reusing simple icons to build more complex ones. Icons can be organized into simple sentences to express drug recommendations. Evaluation showed that VCM was learnt in 2 to 7 hours, that physicians understood 89% of the tested VCM icons, and that they answered correctly to 94% of questions using VCM (versus 88% using text, p = 0.003) and 1.8 times faster (p < 0.001). Conclusion VCM can be learnt in a few hours and appears to be easy to read. It can now be used in a second step: the design of graphical interfaces facilitating access to drug monographs. It could also be used for broader applications, including the design of interfaces for consulting other types of medical document or medical data, or, very simply, to enrich medical texts.


Introduction
"VCM" is a graphical language for the visualization of medical knowledge (Visualisation des Connaissances Médicales in French), destined for health professionals (not rather than patients). VCM can be used to represent medical knowledge with icons. The objective is not to replace medical texts entirely by icons, but rather to combine text and icons, using icons to enable the user to localize pieces of text of interest more rapidly, e.g. during a medical consultation.
The current version of VCM (1.0) focuses on drug knowledge, and on SPCs (Summary of Product Characteristics, corresponding to the drug monographs) in particular. It aims to help you find answers to the following questions: • "What are the main characterictics of this drug?" • "Can I prescribe this drug to my patient?" • "What should I tell my patient about this drug?" This document presents the basics of VCM language, and includes a reference manual with an icon dictionary is included at the end.
VCM distinguishes five basic concepts, each of them is associated with a color: • the current state of the patient, in red, including: diseases and symptoms, -physiological states (e.g. pregnancy), patient characteristics (e.g. age, sex) and lifestyle (e.g. diet, alcohol), • the patient risks, in orange, including: risk of diseases or symptoms, -adverse effects • the patient's antecedents, in brown, • the patient's treatments, in green, • the patient's medical monitoring, in blue.
Each medical concept is represented by an icon, consisting of a combination of colors, geometrical shapes and pictograms. However, VCM can represent only simple or general concepts. More precise concepts are represented by the more general concept that includes them.
These icons can then be used to build simple medical sentences dealing with contraindications, adverse effects, and so on.

The current state of the patient
The current state of the patient is represented using the red color. It includes diseases and symptoms, but also nonpathological states such as pregnancy.

Physiological states, patient characteristics and patient lifestyle
Physiological states, patient characteristics and patient lifestyle are non pathological states. They are represented by a red circle containing a white pictogram; the red color indicates a "current patient state", the circle indicates a "non-pathological state" and the pictogram represents the state. E.g.:

Child
Alcohol consumption

Diseases and symptoms
VCM doesn't does not distinguish between diseases and symptoms. Both are represented as a red square containing a white pictogram; the red color indicates a "current patient state", the square indicates a "pathological state" and the pictogram indicates where the location of the disease or symptom (generally an anatomic or functional site). E.g.: Cardiac disease Alcoholism The same pictogram represents both the anatomical site and the corresponding function (e.g. the same pictogram is used for the lung and for respiration). Diseases and symptoms may use the same pictograms as than non-pathological states, but inside these pictograms are enclosed within a square rather than a circle. Here, alcoholism is represented as a "pathological alcohol consumption".
VCM distinguishes two kinds of pathological states, making it possible to represent diseases and symptoms more precisely: • Pathological states that apply to several sites, e.g. failures (heart failure, renal failure,...), infections (respiratory infections, urinary infections,...), cancers and tumor (pulmonary cancer, intestinal cancer,...), hemorrhages (brain hemorrhage, digestive tract hemorrhage,...). In such cases, the square is modified, the new shape providing further details concerning the type of diseases, e.g.: Heart failure • Pathological states that apply to a single site, e.g. heart rhythm disorders (heart specific), vomiting (stomach specific), epilepsy (specific to the central nervous system). In such cases, a different, more precise, pictogram is used, e.g.:

Heart rythm disorders
These two methods can be combined, e.g. : Tachycardia (increase of the heart rhythm) VCM provides icons only for the most general, important or common diseases and symptoms. Other diseases or symptoms are represented by a more general icon, e.g. VCM represents "cardiac septum abnormality" as

Cardiac disease
The various modifications to the square shape possible include: Increase / hyper-function, e.g.: Hyperthyroidism (hyper-function of the thyroid) Decrease / hypo-fonction / insufficiency / failure, e.g.: Heart failure (failure of the heart) Full decrease / stop / arrest, e.g.:

Cardiac arrest
Pain, e.g.: Headache (pain located in the central nervous system) Inflammation, e.g.:
Coronary disease (vascular disorders located in the heart) Obstructed vessel / embolism / thrombosis, e.g: Heart infarct (obstruted vessel located in the heart) Blood pressure problems, including: Hypertension (increase in blood pressure) Hypotension (decrease in blood pressure) Haemorrhage, e.g.: Digestive tract haemorrhage (haemorrhage located in the digestive tract) Edema, e.g.:

Viral hepatitis (viral infection located in the kidney)
Bacterial infections, e.g.: Bacterial meningitis (bacterial infection located in the central nervous system), Fungus infections / mycosis, e.g.:

Risks of diseases or symptoms
Risks of diseases or symptoms are represented in precisely the same way as the corresponding diseases or symptoms, but in orange, e.g.:

Antecedents of diseases
An antecedent of a particular disease is represented in precisely the same way as the corresponding disease, but in brown, e.g.:

Treatments
Treatments are represented in green.

Non-pharmacological treatments
Non-pharmacological treatments are represented by a green square containing a white pictogram; the green color means "treatment", the square "non-normal state" (we consider patients following a treatment not to be in a "normal" patient state and thus use the square and not the circle for treatment), and the pictogram indicates the type of treatment: Diet Physical activity Surgical treatment

Pharmacological treatments
Drugs are represented by the icon of the disease or symptom the drug is used to treat, with a green cross superimposed on the top right-hand corner. E.g.: Heart failure drug / cardiotonic drug When it is relevant, the route of administration can be specified by replacing the green cross by one of the following pictograms:

Topical drug
Enteral systemic route Parenteral systemic route These pictograms can be used to distinguish between different drug classes, e.g.:

Local anti-asthmatic vs systemic anti-asthmatic
Oral anti-diabetic vs insule treatment Vitamin K inhibitors vs heparin VCM provides icons only for the most general, common or important therapeutical classes. More specific classes or drugs indicated by ICD or brand name are represented by the icon for the corresponding therapeutic class. E.g. for propranolol: Anti-hypertensive drug

Pharmacological treatment properties
The properties of drug treatments are represented by a green square containing a white pictogram; the square may be replaced by the increase, decrease or stop shapes. Events associated with drug administration (e.g. overdose) are represented by a red square, and risks of such events, by an orange square.

Sentences
VCM icons can be combined to build graphical sentences. These sentences can represent sentences extracted from SPCs or drug monographs. The drug described by the SPCs is not explicitely stated in the sentence. So, VCM sentences say e.g. "contraindicated for asthma" and not "drug XXX is contra-indicated for asthma".
In VCM, all sentences follows this pattern: "conditions" are the conditions needed for the rest of the sentence to apply, e.g. a sentence may apply only to patients suffering from a given disease. "effects" indicates the effects or properties of the drug described by the SPC (e.g. adverse effects). "actions to do" and "actions to be avoided" indicate the actions that should be done or that should be avoided.
The conditions are followed by an arrow, all actions are framed and the actions to be avoided are crossed out. The statements are represented "as-is". All the four elements are optional, and if one is not present, it is hidden. E.g. if a sentence has no condition, the "conditions" block and the arrow are hidden.
In some situations, several VCM sentences are required to represented a single safe practice. In this case, the sentences are placed on the same line, and separated by a semi-colon.
("actions to be avoided" with no icon inside) means "do not prescribe the drug described by the SPC". This symbol is frequently used for contraindications.

Combining several icons into a single icon
VCM can combine several icons, representing them by a more general icon, in order to reduce the length of a sentence. E.g. "heart rhythm disorders" and "angor" can be combined and represented as "several cardiac diseases". In this case, a shadow is added behind the icon, to indicate the superimposition of several icons. E.g.

Cardiac disease
Several cardiac diseases

Negations
The icon is negated by crossing it out, e.g.: = Sedentary patient (no physical activity)

Actions
Actions the physician should undertake or avoid may be of different types: Prescribing a treatment: the icon of the treatment of drug to be prescribed is used, e.g.: = The prescription of a diet is recommended = The prescription of an antiemetic is recommended Modifying and stopping the current treatment: the icon corresponding to the modification is used, e.g.:

VCM-English disease and sign dictionary
This dictionary gives the VCM icons for the main diseases and signs; however, it is absolutely not exhaustive.