| 摘要 |
<p>Blood flow in the aorta and pulmonary artery of a mammal, most typically a human, is measured volumetrically by a non-invasive, ultrasound apparatus. A piezoelectric ultrasound transducer (21, 22) is placed in the trachea (T) in great proximity to the aorta or pulmonary artery (A). Ultrasound waves are transmitted toward the path of flow of blood in the artery (A). Reflected waves are received. The average Doppler frequency difference between transmitted and received waves is measured. The cross-sectional size of the artery (A) is measured. Blood flow rate is determined from the measurements. The apparatus comprises a tracheal tube (11) or probe (10) with one or two transducers (21, 22) mounted at one end of the tube. The transducer(s) (21, 22) is (are) disposed to transmit ultrasound in selected directions. Electrical conductors (24-27) extend from the transducers (21, 22) the length of the probe. Inflatable balloons (29, 30) serve to urge the transducer(s) (21, 22) into contact with the inner wall of the trachea (T).</p> |
