System for determining characteristics of blood flow
First Claim
1. In a method for noninvasively measuring rate of blood flow in a section of a living body, the steps ofpassing a signal Z representing impedance of said section through a first channel which includes, in series, a divider device and a multiplier device to obtain a signal (c4 /Zn) where c4 is a constant and n is a value of 2 or more,passing said signal Z through a second channel which includes a differentiator to obtain the signal a (dz/dt) where a is a constant and multiplying said signals (c4 /Zn) and a (dz/dt) in a multiplier to obtain the resulting signal (b/Zn) .sup.. (dz/dt) where b is a constant and where the resulting signal represents the instantaneous rate of flow of blood in said body section.
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Abstract
A method and apparatus for determining and displaying without invasion into the vascular system the instantaneous rate of blood flow, the stroke volume during a pulse or cycle, and the cardiac output over a time period. The system involves an arrangement of electronic units through which a signal representing impedance of a section of a living body is passed in a special order and which results in instantaneous and continuous indication of blood flow characteristics through this section.
A principal feature of the system resides in the provision of two electrical channels one of which contains an electronic divider and the other an electronic differentiator both of which channels are connected with a multiplier which multiplies the signal from one channel with the signal from the other channel to produce a signal representative of the rate of instantaneous blood flow through the body section being tested.
42 Citations
21 Claims
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1. In a method for noninvasively measuring rate of blood flow in a section of a living body, the steps of
passing a signal Z representing impedance of said section through a first channel which includes, in series, a divider device and a multiplier device to obtain a signal (c4 /Zn) where c4 is a constant and n is a value of 2 or more, passing said signal Z through a second channel which includes a differentiator to obtain the signal a (dz/dt) where a is a constant and multiplying said signals (c4 /Zn) and a (dz/dt) in a multiplier to obtain the resulting signal (b/Zn) .sup.. (dz/dt) where b is a constant and where the resulting signal represents the instantaneous rate of flow of blood in said body section.
- 12. In apparatus for determining the instantaneous blood flow in a section of a living body, a channel which includes, in series, divider means for converting its input to an inverse value and multiplier means for raising its input to an exponential power of 2 or more, a second channel which includes a differentiator, means for delivering to one end of each of said channels a signal representative of the impedance of said body section, and means for multiplying signal at the other end of said first-mentioned channel with the signal at the other end of said second channel to produce a signal at its output which is representative of the instantaneous rate of flow of blood in said body section.
Specification