Source:http://linkedlifedata.com/resource/umls/id/C0179610
UMD: Cardiac output units that measure blood volume and flow rate from the heart based on the Fick's law of diffusion. The direct Fick method is based on an assumed value of body oxygen consumption rather than a real measurement of its value. Fick measurement of cardiac output processes the measurements of oxygen consumption, venous blood oxygen, and arterial blood oxygen; a computer unit (or a standard computer) using an algorithm calculates the approximate value of cardiac output as the quotient of total body oxygen consumption divided by the difference in oxygen content of arterial blood and mixed venous blood. This technique is currently used infrequently to measure cardiac output.