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In vitro validation of combined two-dimensional echo/Doppler method for cardiac output
Journal article   Peer reviewed

In vitro validation of combined two-dimensional echo/Doppler method for cardiac output

Surender Singh, Luigi Arena, Ira Gubernick, Steven Bloom, Gaetano Capone, Steven G. Meister and Michael J. Barrett
Ultrasonic imaging, v 5(2), pp 176-176
1983

Abstract

We constructed an artifical aorta with pulsatile flow characteristics to test the accuracy of combined two-dimensional echo/Doppler technique for cardiac output measurement. The two-dimensional echocardiographic system was a phased array instrument with a 2.25 MHz transducer. The cross-sectional area of the aorta was imaged in a short axis view in the focal zone of the transducer (7.5 cm). A 2.25 MHz continuous wave Doppler transducer was positioned at an angle of 50° relative to the aorta. Good signal-to-noise ratios in the Doppler signal were obtained using a suspension of methylcellulose as a red blood cell substitute. The Doppler signal was digitized after passage through a high pass filter. These digitized tracings were averaged over ten beats. These values were then corrected for transducer angle and multiplied by the cross-sectional area of the aorta. The predicted cardiac output by the combined echo/Doppler technique was compared to the absolute cardiac output as measured by a 30 s collection of fluid in a graduated cylinder. Thirty separate cardiac output determinations were made ranging from 0.6 to 7.2 liters/minute. Linear regression analysis yielded the following results: y=O.96x + 0.02, SEEz0.5, r=0.96. Each echo/Doppler measurement was performed a minimum of 5 times with a standard deviation of 5 percent. In conclusion, accurate in vitro cardiac output measurements can be made -- using a combined two-dimensional echocardiographic/Doppler system with excellent results if the cross-sectional area of the aorta and the transducer angle are known.

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Web of Science research areas
Acoustics
Engineering, Biomedical
Radiology, Nuclear Medicine & Medical Imaging
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