See Robert R. Hausam's 1996 article 'Vocabulary, Coding, and Concept Representation' for a concise explanation of what clinicians might want from their computers, and why terminology is needed to make it happen. The original copy is here.
The following extract is taken from a BJHC article (2000) entitled: 'Terminology, Codes, and Classifications - Why it's hard' by Prof AL Rector of the University of Manchester:
The need for controlled vocabulary or 'codes' has become so widely accepted that few stop to ask why they are using codes or specialised terminology in a given situation.
Today, we would like terminology to support at least four functions:
- Clinical data capture and presentation - letting healthcare professionals enter, store, and review what would otherwise be written in the clinical notes
- Information integration, indexing, retrieval - linking clinical records, decision support, quality assurance, and other information, e.g. through the UK National Electronic Library of Medicine.
- Messaging between software systems - linking laboratory and hospital information systems or sending prescriptions from prescriber to dispenser to the Prescription Pricing Authority
- Reporting - providing the official returns in whichever coding system is required
In attempting to fulfil the first two functions, terminology must straddle the line between the flexible context-sensitive world of human language and the rigid logical world of software. It must be quick and flexible for users and rigid and well defined for software. A tall order, especially because even without computers, healthcare language presents difficulties. There are many natural dialects used by different healthcare professionals and specialities. Communication between people is often imperfect, and misunderstandings are common.
When people first began to count and index clinical phenomena, they needed solutions to the ambiguity of ordinary language. Three groups drove the early development of clinical terminologies - epidemiologists, librarians, and accountants. The epidemiologists gave us ICD, ICPC, OPCS , etc; the librarians gave us MeSH; the accountants adapted the epidemiologists codes, e.g. ICD9-CM or invented their own such as DRGs. When computers became available, they were applied to these tasks, but merely to automate what had previously been done manually. The impact on patient care was minimal, and almost all data was entered by special staff.
The introduction of computers to patient care brought with it two new needs for terminology: compactness and symbolic representation. 'Codes' were more compact than text, and this was an important motivation for early terminologies such as the original Read and Oxmis codes which were designed for computers which could often store less than a megabyte per disk. However, technological change has made storage cheap and so compactness is no longer a consideration.
By contrast, technological change has increased the need for symbolic representation. Increasingly, as Information for Health states (a UK policy document on healthcare IT), the goal is that
"…wherever possible information should be a natural by-product of the systems required to support clinical care"
To achieve this, information must be collected from healthcare professionals in the course of patient care and transformed by software so that it can be re-used for other purposes. However, most clinical information is expressed in language; software only manipulates symbols. We need clinical terminology to bridge that gap. The magnitude of these changes in our requirements for terminology - from use by people to use by software, from single purpose use to multi-purpose re-use, and from entry by coding staff to entry by healthcare professionals - is often seriously underestimated.
The next extract is taken from CMO'S UPDATE 25 (Feb 2000)- a regular communication to all doctors from the Chief Medical Officer of England. It demonstrates how difficult it is for humans to know when they are being ambiguous:
The Chief Medical Officer was recently alerted to the problems of confusing medical terminology - a reminder on the importance of accurate communications in all areas of the medical profession.
One example was of a patient investigated with ultrasound venous imagery and reported on as having an incompressible clot in the 'superficial femoral vein', with the intention to treat through anticoagulation. However, the report was interpreted as the patient suffering from superficial thrombophlebitis, resulting in different treatment. Some studies indicate that the term 'superficial femoral vein' appears to be open to several different interpretations [1] . All medical professionals need to be vigilant to the possibility of the use of confusing terminology.
Reference 1. WP Bundens, JJ Bergan, NA Halasz et al. The Superficial Femoral Vein: a potentially lethal misnomer. JAMA; 274: 16, 1296-8. Quality Issues