Patrice Degoulet

Medical Decision Support Systems

The practice of medicine requires the physician to constantly make multiple decisions that are logically related for a given patient. Computers can provide direct or indirect assistance in making these decisions. Hospital information systems (see Chapter 7) and systems for managing patient records (see Chapter 9) are part of the indirect assistance. Simplified access to patient records (e.g., laboratory data) and analytical presentations of data (e.g., reports or summary tables) can also help make decisions and avoid unnecessary or dangerous ones. This may involve providing access to data specific to a given domain, such as bibliographical databases or medical or legal knowledge bases (see Chapter 6).

Managing Patient Records

Patient records are the repository where all the information required for patient care and surveillance is stored (Figure 9.1). As a tool for memorization, records are a central element in health care, and their development follows the more general evolution of the practice of medicine. The information they store is increasingly complex, reflecting the appearance of new methods of investigation, in particular signal analysis, imaging and molecular medicine (see Chapters 10 and 11). Records are physically distributed (e.g., among hospitals, general practitioners, or insurance organizations) and shared among health professionals. They are a necessary a tool for communication.

Medical Imaging Systems

Imaging techniques occupy a growing part of the practice of medicine. They may intervene in the diagnostic, prognostic, or therapeutic decision-makng processes. Medical images include radiological images (conventional radiography or tomography), nuclear-medicine, ultrasound, photography (used in cytology, pathology, dermatology, electrofluoresence or chromosome maps), films (endoscopy), functional images obtained through reconstruction (tomodensitometry, magnetic resonance imaging), or even simulations that create virtual reality.

Computer-Based Education

The practice of medicine implies an aptitude for decision-making based on continuously updated knowledge. The extent of that knowledge can only increase. The goal of medical education is to prepare tomorrow’s physicians by providing them with the knowledge required to practice medicine. It must also help students master the technologies necessary to manage and process medical information. These technologies are involved in the processes of building, communicating, and validating knowledge. Computer-based education (CBE) can be used by itself or as a complement to traditional methods. The large number of tools available represent situations that educators have identified and developed to assist in the learning process. Pedagogical materials related to a session must be structured and put in a form that can be used by educational software.

Documentation Systems and Information Databases

The number of cataloged medical periodicals is increasing exponentially, doubling approximately every 10 to 15 years, and today surpasses 20,000. There are more than 250,000 individualized medical concepts in the UMLS metathesaurus (see Chapter 5). Unfortunately, the time physicians and researchers are able to devote to reading scientific texts is not expandable. Given this situation, it is easy to imagine the need to use automatic systems to access medical knowledge.

Medical Software Development

The cost of software, both for developing and maintaining programs, represents a growing part of computing budgets and sometimes exceeds hardware costs. The increase in these costs, observed over the past 20 years, is largely due to the growing complexity of the problems to be solved and to the ever-changing requirements of users. Some programs, such as hospital information systems, represent several million lines of code and involve teams of several hundred programmers.

Analysis and Control of Medical Activity

The cost of health care continues to rise in most countries. Several factors are responsible for this phenomenon: the development of new medical techniques, the increased scope of health care, the aging of the population, improvements in the standard of living, and a general population that is better informed about needs and demand. In parallel, the use of inappropriate therapeutic techniques and unproductive or dangerous investigatory techniques is difficult to control and can cause major discrepancies in medical practice. Increased costs are not synonymous with increased health-care quality, and reorganizing the health-care system does not guarantee improvement in the quality of health care provided.

Physiological Signal Processing

Several clinical situations lend themselves to the repetitive, closely grouped measurement of physiological parameters. These include recording electrical signals and measuring pressures, frequencies, volumes, flows, or temperatures. In general, physiological signals vary continuously over time. Data are captured using specialized captors that transform the input signal into an electrical signal that may be amplified and visualized on a cathode ray tube. Transforming the analog signal into digital data simplifies processing, storage, and transmission. This chapter briefly presents the objectives and bases for signal processing and describes a few significant examples.

Medical Language and Classification Systems

Medical language uses an extremely rich and difficult vocabulary. The terms employed are often vague and imprecise and are seldom rigorously defined. The same disease may be known under several names or expressions, known as synonymy. Inversely, a single term may have several meanings according to the speaker and the context, known as polysemy.

Systems for Managing Medical Information

Informatics, the science of information management, employs a variety of techniques to automate the collection, storage, utilization, and transmission of information. Because it relies on the use of computers, informatics requires that information be represented in an encoded, computer-readable format.