Airflow perturbation device and method for measuring respiratory resistance
First Claim
1. An airflow perturbation device, comprising:
- a housing;
an airflow/differential pressure conversion device on an input side of said housing, said airflow/differential pressure conversion device having an input and an output and first and second pressure taps thereupon;
an alternating perturbation mechanism movably attached to said housing and disposed at the output of said airflow/differential pressure conversion device, said alternating perturbation mechanism alternatingly blocking and unblocking the output of the airflow/differential pressure conversion device;
a moving device attached to said housing for moving said alternating perturbation mechanism;
a first pressure transducer connected to said first differential pressure tap for determining a first differential pressure;
a second pressure transducer attached to said second differential pressure tap for determining a second differential pressure; and
a perturbation adjustment mechanism on the input side of the housing, said perturbation adjustment mechanism for adjusting a perturbation level, said perturbation level determined based upon output from the first and second pressure transducers,said first and second pressure transducers providing an output signal which is provided to a signal processing means for determining parameters associated with a respiratory system of a patient inhaling and exhaling through the airflow/differential pressure conversion device.
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Accused Products
Abstract
An airflow perturbation device and system wherein airflow of a subject is alternatingly blocked and unblocked by a mechanism to provide an output of an airflow/differential pressure conversion device based on oscillating differential pressure signals created by the alternating perturbation. The signals are provided by pressure transducers which provide signals to a data acquisition computer which calculates respiratory resistance as an indicator of airway resistance. An airflow perturbation device according to the invention could be a self-contained unit wherein the airflow perturbation mechanism, differential pressure conversion device, transducers, and data acquisition computer are in a single unit. In another embodiment, an airflow perturbation device could include the airflow perturbation mechanism and pressure transducers in a single unit, and provide transducer output to the data acquisition computer for calculation of respiratory resistance.
139 Citations
26 Claims
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1. An airflow perturbation device, comprising:
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a housing; an airflow/differential pressure conversion device on an input side of said housing, said airflow/differential pressure conversion device having an input and an output and first and second pressure taps thereupon; an alternating perturbation mechanism movably attached to said housing and disposed at the output of said airflow/differential pressure conversion device, said alternating perturbation mechanism alternatingly blocking and unblocking the output of the airflow/differential pressure conversion device; a moving device attached to said housing for moving said alternating perturbation mechanism; a first pressure transducer connected to said first differential pressure tap for determining a first differential pressure; a second pressure transducer attached to said second differential pressure tap for determining a second differential pressure; and a perturbation adjustment mechanism on the input side of the housing, said perturbation adjustment mechanism for adjusting a perturbation level, said perturbation level determined based upon output from the first and second pressure transducers, said first and second pressure transducers providing an output signal which is provided to a signal processing means for determining parameters associated with a respiratory system of a patient inhaling and exhaling through the airflow/differential pressure conversion device. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10)
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11. An airflow perturbation system, comprising:
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an airflow perturbation device for generating signals regarding respiratory parameters of a patient, said airflow perturbation device including an input device for receiving exhaled air from the patient, said input device comprising an airflow/differential pressure conversion device on an input side of a housing of the airflow perturbation device, with the airflow/differential pressure conversion device having first and second pressure taps thereupon; a data acquisition device connected to said airflow perturbation device, said data acquisition device acquiring the signals output from the airflow perturbation device, said data acquisition device including storage means for storing a plurality of sets of data over a predetermined period of time, said data acquisition device including a processing device for calculating at least one of lung volume of the patient, perturbation data, virtual data, and respiratory resistance; an alternating perturbation mechanism movably attached to said housing and disposed at an output of said airflow/differential pressure device, said alternating perturbation mechanism alternatingly blocking and unblocking the output of the airflow/differential pressure device; a moving device attached to the housing for moving said alternating perturbation mechanism; a first pressure transducer connected to said first differential pressure tap for determining a first differential pressure; a second pressure transducer attached to said second differential pressure tap for determining a second differential pressure, said first and second pressure transducer each providing an output signal provided to said data acquisition device, wherein said data acquisition device stores the plurality of sets of data from the first and second pressure taps over the predetermined period of time, and said processing device calculating the at least one of lung volume, perturbation data, virtual data, and respiratory resistance based upon the output from the first and second pressure transducers and a perturbation adjustment mechanism on the input side of the housing, said perturbation adjustment mechanism for adjusting a perturbation level of the airflow perturbation device, said perturbation level being adjusted so that a device resistance provided by said airflow perturbation device provides an appropriate sensitivity based upon a respiratory resistance of a patient. - View Dependent Claims (12, 13, 14, 15, 16, 17, 18, 19)
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20. A method for determining respiratory parameters of a patient, said method comprising the steps of:
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generating airflow perturbation signals from an airflow perturbation device based upon inhalation and exhalation of a patient; adjusting a perturbation level of the airflow perturbation device such that a device resistance provides an appropriate sensitivity based upon a respiratory resistance of a patient; inputting said signals into a data acquisition computer; determining a start and stop of a perturbation generated in said airflow determination device; estimating virtual data for pressure and flowrate of non-perturbed airflow; determine perturbation magnitude based upon the perturbation data and the estimated virtual data; calculating respiratory resistance based upon said perturbation magnitudes and said virtual data; storing said calculation resistance in a memory, as a stored resistance value. - View Dependent Claims (21, 22, 23, 24, 25)
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26. A computer program for determining respiratory parameters of a patient, said computer program embodied on a computer readable medium, and controlling a data acquisition computer and a respiratory resistance measuring device to perform the steps of:
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generating airflow perturbation signals from an airflow perturbation device based upon inhalation and exhalation of a patient; adjusting a perturbation level of the airflow perturbation device such that a device resistance provides an appropriate sensitivity based upon a respiratory resistance of a patient; inputting said signals into a data acquisition computer; determining a start and stop of a perturbation generated in said airflow determination device; estimating virtual data for pressure and flowrate of non-perturbed airflow; determine perturbation magnitude based upon the perturbation data and the estimated virtual data; calculating respiratory resistance based upon said perturbation magnitudes and said virtual data; storing said calculation resistance in a memory, as a stored resistance value.
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Specification