System for measuring respiratory function
First Claim
1. A method for characterizing airway obstruction of a conscious living organism, comprising the steps of:
- obtaining a first input signal using a constant volume plethysmograph system having a head-out, breath-in chamber, the first input signal being a pressure differential signal indicative of alveolar pressure during breathing by said living organism in a chamber;
obtaining a second input signal from a second sensor indicative of nasal airflow of said living organism; and
processing said first input signal and said second input signal to calculate at least a third signal indicative of airway resistance; and
characterizing airway obstructions of said living organism using the at least third signal.
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Abstract
The present invention relates to a system for measuring respiratory function of living organisms. More particularly, signals indicative of the change in lung volume, defined as active and passive work, required to breathe and the airflow through the respiratory system of the living organism are obtained and processed as waveforms to provide a signal indicative of the respiratory restriction. The methods of the present invention measure clinical forms of airway obstruction, airway reactivity and lung volume and may be used to continuously or intermittently monitor patients with compromised respiratory function. In a preferred embodiment, a head-out, breath in respiratory plethysmograph system provides the signals indicative of change in lung volume as related to pressure changes in a chamber. Further, flowmetric variables are generated that provide a characterization of airway obstructions.
212 Citations
51 Claims
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1. A method for characterizing airway obstruction of a conscious living organism, comprising the steps of:
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obtaining a first input signal using a constant volume plethysmograph system having a head-out, breath-in chamber, the first input signal being a pressure differential signal indicative of alveolar pressure during breathing by said living organism in a chamber;
obtaining a second input signal from a second sensor indicative of nasal airflow of said living organism; and
processing said first input signal and said second input signal to calculate at least a third signal indicative of airway resistance; and
characterizing airway obstructions of said living organism using the at least third signal. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18)
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19. A method for characterizing airway obstruction of a conscious living organism comprising the steps of:
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obtaining a first input signal indicative of a change in lung volume as related to a pressure change in a constant volume, head out, breath in plethysmograph chamber;
converting said first input signal from an analog signal to a digital signal;
taking the derivative of said digital first input signal to generate a signal indicative of thoracic flow;
converting the second input signal from an analog to a digital signal;
taking the derivative of the second input signal to generate a signal indicative of nasal airflow; and
dynamically comparing the signals indicative of thoracic flow and nasal airflow. - View Dependent Claims (20, 21, 22, 23, 24)
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25. A system for characterizing airway obstruction of a conscious mammal, comprising:
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a constant volume plethysmograph having at least one head out, breath in chamber having a plurality of sensors disposed therein, and a data collection and processing system in communication with the constant volume plethysmograph. - View Dependent Claims (26, 27)
a device that obtains a second input signal indicative of nasal flow.
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27. The system of claim 25, wherein the first and second input signals are processed in the data collection and processing system to calculate a plurality of signals indicative of respiration function.
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28. An apparatus for measuring airway obstructions in a conscious mammal, comprising:
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at least one chamber having a constant volume and at least one pressure sensor to obtain a first input signal indicative of alveolar pressure of the conscious mammal, the at least one chamber provides for a head-out breath-in configuration for the conscious mammal;
a device to obtain a second input signal indicative of nasal flow, and a processing device in communication with the chamber to calculate a third signal by comparing the first and second input signals to characterize airway obstructions of the mammal. - View Dependent Claims (29, 30, 31, 32, 33, 34, 35, 36, 37, 38, 39)
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40. A portable apparatus for measuring pulmonary function in a conscious mammal, comprising:
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at least one headout, breath in chamber having a constant volume and at least one pressure sensor to obtain a first input signal indicative of alveolar pressure of the conscious mammal;
a device to obtain a second input signal indicative of nasal flow, and a processing device in communication with the chamber to calculate a third signal by comparing the first and second input signals to characterize airway obstructions of the mammal. - View Dependent Claims (41, 42, 43, 44, 45, 46, 47, 48, 49, 50, 51)
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Specification