A novel instrument for investigation of aortic haemodynamics

We present a unique experimental set-up addressed to provide detailed information about blood dynamics in the aorta. The set-up is based on an esophageal probe (EP) connected to a multigate Doppler-processing system. The EP probe, which was developed for the noninvasive hemodynamic monitoring of aortic blood velocities in patients under anesthesia or in the intensive care area, must be inserted at a depth where the esophagus and the aorta are nearby and parallel. The multigate system evaluates in real-time the distribution of Doppler frequencies produced along the probe beam axis, and displays the computation results in form of velocity profiles. Preliminary results of this investigation show that the velocity profiles highly depend on the measurement site. When blood velocity is detected at the aortic arch level the profiles look quite irregular, always being non-axis symmetric and including both positive and negative components. More regular profiles were found in the descending aorta, where they tend to be flat during systole and close to zero during diastole