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Show Oxygen Measuring j Device Is Small, j Inexpensive, Precise j In this age of life-saving medical devices where big is often considered better and expensive price tags are impressive, University of Utah researchers are breaking the rules. THE scientists have developed a novel technique to measure the oxygen consumed con-sumed by critically ill patients pa-tients in the intensive care unit - from the newborn to bum patients. One central idea has spawned several instruments that are small, inexpensive, practical, accurate, easy to use and that provide continuous con-tinuous measurements and do not harm the patient. THE CONCEPT of the noninvasive measurement of oxygen consumption was the vision of the late Dr. Curtis C. Johnson of the University of Utah Bioengineering Department. Depart-ment. The research has been carried on by a number of scientists, including Dr. Dietrich Die-trich K. Gehmlich, professor of electrical engineering and adjunct professor of bioengineering, bioen-gineering, and Dr. Dwayne R. Westenskow, assistant professor of anesthesiology, bioengineering and surgery. "ALL TISSUES in the body use oxygen to maintain the function of the cells," explains Westenskow. "This basic metabolic rate should be fairly constant. If the metabolic me-tabolic rate suddenly increases or decreases, that may indicate the patient is entering an abnormal state. Continuous monitoring of whole body oxygen consumption consump-tion appears to be a useful indicator of many things such as the depth of anesthesia, hypoxia (lack of oxygen), predicting and diagnosing certain types of shock, calculating cal-culating cardiac output and indirectly calculating metabolic me-tabolic rate. DESPITE THE apparent usefulness of this measurement, oxygen consumption con-sumption is not usually measured routinely in the intensive in-tensive care unit because the equipment is bulky, expensive expen-sive and inaccurate in many "Our system provides a continuous measurement of oxygen consumption which shows gradual changes in the patient's condition," says Gehmlich. "WHAT WE have," he continues, con-tinues, "is a precise measuring measur-ing device attached to a respirator res-pirator that eliminates the traditional problems in measuring gas concentrations and respiratory flow. It can be operated by the ICU staff and won't harm the patient." "Some research centers use mass spectrometers and computers, to take oxygen consumption measurements, but such systems run up to $100,000," explains Westenskow. Wes-tenskow. "Our instrument will cost about $6,000." OFTEN, IN cases of severe injury, oxygen consumption measurements can be useful, says Gehmlich. "If we know the metabolic rate of ICU patients, pa-tients, we can determine the proper intravenous nutrition required." "Babies in the intensive care unit are particularly difficult dif-ficult to care for because they are so small," notes Westenskow. Wes-tenskow. "If they're either too cold or too warm, they use more oxygen." "WE USE the same technique tech-nique to measure oxygen consumption in babies," Gehmlich points out, "but we added a special valve that is placed next to the baby's mouth, which provides a very accurate and immediate measurement without inter- . ferring with routine i.i. therapy." 7 "Knowing the rate of oxygen consumed tells the doctor how many calories are being burned," explains Westenskow. "In the ICU the patient should use calories derived from fats and carbohydrates, car-bohydrates, not from protein, because protein comes out of the patient's muscle mass," Westenskow savs. "OUR NEWEST unit will-tell will-tell us how much carbon dioxide is produced as well as how much oxygen is consumed, con-sumed, and whether the body is using carbohydrates, fats or proteins. We'll use this information in-formation to determine the proper intravenous feeding mixture," he says. Burn patients also present special problems in care because they are in a hypermetabolic state. "Oxygen consumption can be as much as 50 to 100 percent above normal. By keeping track of changes in oxygen consumption, treatment can be started to lower oxygen consumption so that the heart and lungs can more easily support the body functions," explains Westenskow. ACCORDING to Gehmli,K t the simplicity and prta 0h ' of the technique makeS f Also, the instrument use, i only the exhaled air (romU I patient, so there J problem with bacteria 'Z eel that's a very strong plu fo; "he instrument," headi" Others involved in .hp research are Dr. Bruce 7 Houtchens, assistant proles' sor of surgery; Dr. C. Peter Richardson, research assis tant professor in pediatrics; Dr. William S. Jordan as sociate professor ' ( anesthesiology; and Dr Daniel B. Raemer, depart! t ments of surgery and bioen- gineering, all of the univer ' sity. THE RESEARCH has ! received considerable local ' support, as well as grants from the National Institutes ol ' Health, Draegerwerk AlT West Germany, and Emers Co. of Japan. |
