Noninvasive aortic blood flow measurement using an intraesophageal probe.

The continuous measurement of cardiac output by the thermodilution technique is invasive, impractical and unpleasant for the patient. This paper describes the measurement of aortic blood flow with a specially designed intraesophageal echo Doppler probe. An A-scan unit allows the measurement of the diameter of the thoracic aorta and a continuous wave Doppler velocimeter is used for measurement of instantaneous blood flow velocity. In vitro experimental results as well as clinical studies are presented.