An interdisciplinary field in which the principles, laws, and techniques of engineering are applied to facilitate progress in medicine, biology, and other life sciences. Biomedical engineering encompasses both engineering science and applied engineering in order to define and solve problems in medical research and clinical medicine for the improvement of health care. Biomedical engineers must have training in anatomy, physiology, and medicine, as well as in engineering. In particular, biomedical engineering entails the design and development of tools and instrumentation to enhance the ability of physicians and life scientists to obtain information on physiological and biological processes, and to aid in the treatment of diseases or other abnormalities. It is also an important component in the design and development of artificial organs, limbs, and other prosthetic devices that replace missing body parts or that enhance deteriorated physiological functions (see illustration). Biomedical engineering contributes to medical and biological research aimed at learning more about the functional processes in various physiological systems. An important part of biomedical engineering research is the use of computer techniques to develop mathematical models of physiological functions and processes to expand available theoretical knowledge. See also: Biomechanics; Biomedical chemical engineering; Control systems; Engineering; Engineering design; Medical control systems; Medicine; Simulation
Various instruments are available to the physician and surgeon to facilitate the diagnosis and treatment of diseases and other malfunctions of the body. A primary objective in the development of such medical instrumentation is to obtain the required results with minimal invasion of the body. (Invasion refers to the penetration of the skin or external integument, usually involving increased risk and trauma to the patient.)
Medical diagnosis requires knowledge of the condition of specified organs or systems of the body, and a vast array of instrumentation has similarly been developed for that purpose. For example, much can be learned about healthy or diseased cardiac function through electrocardiography (EKG), the measurement and analysis of the electrical activity of the heart. Electrocardiographic signals are used to measure heart rate and to identify certain types of abnormalities within the heart. They also serve as a means of synchronizing other measurements with cardiovascular activity. Techniques for studying other organs that generate bioelectrical signals have also been developed. See also: Biopotentials and ionic currents; Cardiac electrophysiology; Electrodiagnosis
Instrumentation is used in many ways for the treatment of disease. Devices can control the automated administration of medications or other substances (for example, insulin for diabetics). In some cases, the rate at which the substance is administered is controlled by the level of certain constituents of the blood or other body fluids. See also: Drug delivery systems
The responsibility for the correct installation, use, and maintenance of all medical instrumentation in the hospital is usually assigned to individuals with biomedical engineering training. This phase of biomedical engineering is termed clinical engineering and often involves the provision of training for physicians, nurses, and other hospital personnel who operate the equipment. Another responsibility of the clinical engineer is to ensure that the instrumentation meets functional specifications at all times and poses no safety hazard to patients. In most hospitals, the clinical engineer supervises one or more biomedical engineering technicians in the repair and maintenance of the instrumentation.
The application of engineering principles and techniques has a significant effect on medical and biological research aimed at finding cures for a large number of diseases, such as heart disease, cancer, and acquired immune deficiency syndrome (AIDS), and at providing the medical community with increased knowledge in almost all areas of physiology and biology. Moreover, the data obtained by medical and biological research are used to develop more realistic and sophisticated prosthetic devices, making possible better methods of control and better understanding of the natural systems that the prostheses are designed to replace.
A significant role for biomedical engineers in research is the development of mathematical models of physiological and biological systems. A mathematical model is a set of equations that describe a physiological or biological function in keeping with physical and chemical laws. Modeling can be done at various physiological levels, from the cellular or microbiological level to that of a complete living organism, and can be of various degrees of complexity, depending on the functions to be represented and the requirements for how fully the model should simulate natural function. A major objective of biomedical engineering is to create models that (1) more closely approximate the natural functions that they represent and (2) satisfy as many of the conditions encountered in nature as possible. See also: Mathematical biology
Artificial organs and prosthetics
A highly important contribution of biomedical engineering is in the design and development of artificial organs and prosthetic devices that replace or enhance the function of missing, inoperative, or inadequate natural organs or body parts. For example, hemodialysis units, which perform the functions of the kidney, have been in use for a long time, but most are large external devices that must be connected to the patient periodically to remove wastes from the body. A major goal in this area is to develop small, self-contained, implantable artificial organs that function as well as the natural organs, which they can then permanently supersede.
Artificial hips, joints, and many other body structures and devices designed to strengthen or reinforce weakened structures must be implanted and must function for the life of the patient. They must be made of biocompatible materials that will not cause infection or immunologic rejection by the body. They must also be built with sufficient reliability to minimize the need for adjustment, repair, or replacement. See also: Absorbable orthopedic implants; Artificial spinal disc replacement
Another area in which biomedical engineers are involved is in the creation of sophisticated artificial limbs for amputees and neural prostheses to facilitate or strengthen the use of nonfunctional limbs. Prosthetic limbs attempt to replicate the vital features of natural limbs with miniature electric motors (or other actuators) acting as muscles to operate the moving parts. Control of the movements is a major challenge, especially for the arm and hand, for which the need to provide dexterity to the user is particularly acute. See also: Prosthesis
The goal of rehabilitation engineering is to increase the quality of life for physically disabled persons. One major part of this field is directed toward strengthening weakened motor functions through the use of special devices and procedures that control exercising of the muscles involved. Another part is devoted to enabling physically disabled persons to function better in the world and live more satisfying lives. Devices to aid the blind, the deaf, and those with low vision or low hearing fall within this specialty. In addition, human-factors engineering is utilized in modifying the home and workplace to accommodate the special needs of people facing physical challenges in everyday life. See also: Hearing aid; Human-factors engineering