Prelude
Modern health care has benefited enormously from the work of biomedical engineers to create instruments that are used in clinical monitoring and laboratory analysis. Hospital operating rooms, emergency rooms, and doctors' offices each contain an array of instruments used to measure and record a patient's vital signs such as temperature, blood pressure, pulse, and oxygen saturation (Figure 11.1). Many of the most popular instruments enable noninvasive monitoring of vital signs of patient health: The stethoscope allows doctors to listen reliably to the beating heart, the sphygmomanometer allows them to estimate pressure within vessels deep in the body (Figure 11.2), and the ophthalmoscope allows them to see structures on the retina. It is impossible to estimate the number of lives that have been lengthened or improved by these devices.
The medical device industry—the constellation of large and small companies that design, manufacture, and sell medical devices and instruments—is one of the largest and most rapidly growing sectors of the U.S. economy. Medical device companies employ biomedical engineers to invent, design, build, and test devices for use in medicine. Biomedical engineers also provide technical training to physicians on the use of such devices. Some biomedical engineers work in hospitals overseeing maintenance of medical instruments and adapting instruments to serve patients and doctors: These individuals are often called clinical engineers. In research laboratories, biomedical engineers and other scientists routinely use instruments to take measurements (Figure 11.3). For example, researchers use instruments called spectrophotometers to measure light absorption within liquid samples to quantify the rates of enzymatic reactions or to measure the composition or viability of cells. Microscopes are used to view cells in preparations such as blood smears, which are routinely used to diagnose blood diseases.
The next generation of medical devices and laboratory instruments will provide patients, physicians, and researchers with more information, more rapidly than the instruments of today.