Automatic electronic apparatus for measuring the bronchial resistance and the elastance of the pulmonary tissue
First Claim
1. Automatic electronic apparatus for measuring and displaying simultaneously the resistance R to air flow through the bronchial tracts and the elastance E of the pulmonary tissue of a subject, the parameters R and E being included in the known Rohrer equation
wherein variables p(t), v(t) and v(t) are instantaneous values, with reference to their mean values, of endothoracic or buccal pressure, buccal or endotracheal air flow, and volume of pulmonary air, respectively, and wherein the variables p(t) and v(t) are convertible to a first voltage signal and a second voltage signal, respectively proportional to the pressure and air flow, said apparatus comprising;
a. first means for preamplifying said first voltage signal;
b. second means for preamplifying said second voltage signal;
c. first means, responsive to said preamplified first voltage signal, for correcting for slow drift of said preamplified first voltage signal to generate a third voltage signal of zero mean value of the pressure;
d. second means, responsive to said preamplified second voltage signal, for correcting for slow drift of said preamplified second voltage signal and for integrating said preamplified second voltage signal to generate a fourth voltage signal of zero mean value of the air volume;
e. first automatic computing means, responsive to said third voltage signal and said preamplified second voltage signal, for generating a fifth alpha voltage signal representing R and a sixth error signal which is cancelled when said fifth voltage signal represents the correct value of R;
f. second automatic computing means, responsive to said third voltage signal and said fourth voltage signal, for generating a seventh beta voltage signal representing E and an eighth error signal which is cancelled when said seventh voltage signal represents the correct value of E;
g. first means, responsive to said fifth and sixth signals, for displaying the correct value of R; and
h. second means, responsive to said seventh and eighth signals, for displaying the correct value of E.
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Abstract
The invention relates to medical science.
According to the invention, the resistance to air flow through the bronchial tracts and the elastance of the pulmonary tissue are measured and displayed, starting from signals which represent the respiratory air flow and the variation in endothoracic pressure, by means of an apparatus which comprises a flow signal preamplifier, a pressure signal preamplifier, two automatic calculating devices and an electronic control combination.
The apparatus makes it possible to use endothoracic pressures measured via the central venous system and can possess an alarm signal which is triggered automatically if the values displayed are memorized values.
30 Citations
9 Claims
- 1. Automatic electronic apparatus for measuring and displaying simultaneously the resistance R to air flow through the bronchial tracts and the elastance E of the pulmonary tissue of a subject, the parameters R and E being included in the known Rohrer equation
- space="preserve" listing-type="equation">p(t) = R v(t) + E v(t)
wherein variables p(t), v(t) and v(t) are instantaneous values, with reference to their mean values, of endothoracic or buccal pressure, buccal or endotracheal air flow, and volume of pulmonary air, respectively, and wherein the variables p(t) and v(t) are convertible to a first voltage signal and a second voltage signal, respectively proportional to the pressure and air flow, said apparatus comprising; a. first means for preamplifying said first voltage signal; b. second means for preamplifying said second voltage signal; c. first means, responsive to said preamplified first voltage signal, for correcting for slow drift of said preamplified first voltage signal to generate a third voltage signal of zero mean value of the pressure; d. second means, responsive to said preamplified second voltage signal, for correcting for slow drift of said preamplified second voltage signal and for integrating said preamplified second voltage signal to generate a fourth voltage signal of zero mean value of the air volume; e. first automatic computing means, responsive to said third voltage signal and said preamplified second voltage signal, for generating a fifth alpha voltage signal representing R and a sixth error signal which is cancelled when said fifth voltage signal represents the correct value of R; f. second automatic computing means, responsive to said third voltage signal and said fourth voltage signal, for generating a seventh beta voltage signal representing E and an eighth error signal which is cancelled when said seventh voltage signal represents the correct value of E; g. first means, responsive to said fifth and sixth signals, for displaying the correct value of R; and h. second means, responsive to said seventh and eighth signals, for displaying the correct value of E. - View Dependent Claims (2, 3, 4, 5, 6, 7)
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8. Automatic computing apparatus for generating a signal R, which is the resistance to air flow through the bronchial tracts of a subject, in response to first signals representing endothoracic or buccal pressure and the zero mean value of the pressure, and in response to second signals representing the variation in buccal or endotracheal air flow, comprising:
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a. differential amplifier means; b. first means for generating alpha signals; c. second means, responsive to said alpha signals and said second signals, for generating third signals which are proportional, by said alpha signals, to said second signals, said differential amplifier means providing difference signals corresponding to the difference between said third signals and said first signals; d. means for multiplying said difference signals and said second signals to produce fourth signals; and e. means for integrating said fourth signals over the whole period of each respiratory cycle of a subject to produce fifth error signals which are cancelled when said alpha signals represent a correct value of signal R, said first means for generating including means for memorizing said integrated fourth signals to provide said alpha signals.
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9. Automatic computing apparatus for generating a signal E, which is the elastance of the pulmonary tissue of a subject, in response to first signals representing endothoracic or buccal pressure and a zero mean value of the pressure, and in response to second signals representing the volume of pulmonary air and the zero mean value of the air volume, comprising:
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a. a differential amplifier means; b. first means for generating beta signals; c. second means, responsive to said beta signals and said second signals, for generating third signals which are proportional, by said beta signals, to said second signals, said differential amplifier means providing difference signals corresponding to the difference between said third signals and said first signals; d. means for multiplying said difference signals and said second signals to produce fourth signals; and e. means for integrating said fourth signals over the whole period of each respiratory cycle of a subject to produce fifth error signals which are cancelled when said beta signals represent a correct value of signal E, said first means for generating including means for memorizing said integrated fourth signals to provide said beta signals.
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Specification