| 摘要 |
A method and apparatus for determining the rate of flow of a substance such as blood in a closed circulatory system whereby a detectable indicator substance is injected into the blood upstream of the heart and the density of that substance in the blood downstream measured and integrated in time to determine the flow of blood pumped through the heart in volume units per time. Distortion of the density waveform by recirculation and consequent error in the calculated flow rate is avoided by detecting two points on the exponential decay from the density peak and extrapolating the integral of the remainder of the wave form from these points. In contrast to prior art techniques, an analogue signal reflecting the integral of the waveform is produced and employed to obtain the flow of blood through the heart.
|
