Two-beam pulsed Doppler cardiac output measurement: reproducibility and agreement with thermodilution.

Two observers used two-beam pulsed Doppler ultrasound, equipped with a suprasternal probe, to measure cardiac output (Qt Dopp ) in 38 ICU patients who had pulmonary artery catheters and in 20 adult volunteers. The two-beam pulsed Doppler method enables one device to measure simultaneously both aortic blood velocity and aortic diameter. Each observer was blind to the other's measurement and to the thermodilution cardiac output measurement (Qt td )