Science
| By : Gurpreet Kaur | Previous | Next |
| Posted on : 02 Sep, 2005 | Total Views : 284 |
ELECTRONICS 3
Medical Electronics
Electronic devices other than the large-scale computer that have assisted the medical profession are the radio pill and cardiac pacemaker. The radio pill is an ultra-compact FM transmitter encapsulated in a plastic tube the size of a common cold pill. The pill is swallowed by the patient and the signals that are transmitted enable the physician to chart the patient's digestive tract. The cardiac pacemaker is another small electronic assembly which applies properly timed electrical impulses to the heart when the patient's natural action misses or falters. During lengthy heart surgery, an external artificial heart—abundant with electronic circuits—is used to bypass the patient's own heart and fulfill the organ's functions.
Two new diagnostic aids have been developed by medical electronic researchers to combat heart disease. Both are designed to spot heart abnormalities in the early stage, while chances for treatment and successful surgery are high. One enables the physician to detect pericardial effusion, a specific symptom linked to heart failure. The second aid involves a new electronic treatment that can pinpoint a variety of abnormal heart sounds.
Pericardial effusion is evidenced by the presence of fluid around the heart. Previously, this condition was traced by puncturing the membrane around the heart or else by circulating a material opaque to X rays to make the heart show up in a radiograph. Both approaches were time-consuming and troublesome. The pericardial effusion detector, developed at the University of Rochester School of Medicine and Dentistry, requires an ultrasonic transducer to be placed against the patient's chest. A portion of the sound waves is reflected back to the transducer by the patient's body structure. However, fluid around the heart has a different density from that of surrounding tissues and alters the intensity of the echo reaching the transducer. An oscilloscope displays the returned echo. The pattern produced by a patient with a healthy heart is markedly different from that shown when pericardial effusion is present.
A variety of heart abnormalities can be traced by a PhonoCardioScan, marketed by Beckman Instruments. About the size of an attaché case, the electronic instrument contains two electrodes and a microphone which are attached to the patient's chest. The patient's heartbeat is converted into electrical voltages which are compared with an electronic analog of a normal heart's sound. The results of the comparison are presented in digital form and indicate whether the patient's heartbeat is normal or not. The examiner does not have to analyze the digital data; he can forward the data by phone link for medical interpretation. This instrument is being tested on 10,000 Chicago school children in a program sponsored by the U.S. Public Health Service, the Illinois Department of Public Health, and the Chicago Heart Association.
