A new approach to the noninvasive measurement of cardiac output using an annular array Doppler technique--II. Practical implementation and results.
An experimental Doppler flowmeter system has been developed which can noninvasively measure blood flow volume rate in a vessel. It is based on the attenuation compensated technique and does not require knowledge of the vessel size or beam-vessel angle. In vitro results have shown that the measurement of volume flow rate is independent of vessel angle to within +/- 4%, and independent of vessel diameter to within +/- 5%. Flow rate linearity is better than +/- 3%. A good comparison has been obtained, in vivo, of aortic diameters measured by an imaging system and with this flowmeter; the r value was 0.98. The noninvasive measurement of cardiac output using this flowmeter has been compared with conventional dilution techniques in 54 patients, with a resulting correlation coefficient of r = 0.96.
Evans
J M
JM
Department of Medical Physics, Bristol General Hospital, England.
Skidmore
R
R
Baker
J D
JD
Wells
P N
PN
D001011:Aorta / Q000033:anatomy & histology / Q000502:physiology; D001783:Blood Flow Velocity; D001808:Blood Vessels / Q000033:anatomy & histology; D002302:Cardiac Output; D006801:Humans; D007201:Indicator Dilution Techniques; D008961:Models, Structural; D012212:Rheology; D014463:Ultrasonography / Q000295:instrumentation / Q000379:methods*