ABSTRACT

The use of Doppler ultrasound to measure blood flow and cardiac output is not new.

Originally, blood flow in the ascending aorta was measured at the suprasternal notch. The

technique, however, was difficult to reproduce and the interindividual variability high. In

the past 15 years, transesophageal Doppler monitoring measuring blood flow in the

descending aorta has become more popular and reliable as a clinical tool, although some

manufacturers have again started to produce suprasternal probes.