Method and apparatus for detection and diagnosis of airway obstruction degree
First Claim
1. A method of determining the airway impedance of a patient comprising the steps of:
- supplying breathable gas to the patient'"'"'s airways with an interface;
applying a selected audio-frequency oscillation component to a pressure of the breathable gas;
measuring pressure and flow of the breathable gas in the interface to obtain pressure and flow data characteristic of the patient'"'"'s airway;
converting the pressure and flow data to the frequency domain; and
obtaining a mathematical function of the processed pressure and flow data to determine an index of airway impedance or degree of airway obstruction.
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Accused Products
Abstract
A pressurized breathable gas, preferably air, is supplied to the patient'"'"'s airways with an interface including a mask and a flexible hose. A selected oscillation component or forced probing signal is applied or superposed on the pressurized breathable gas, preferably with a loudspeaker coupled to a frequency generator. Pressure and flow of the breathable gas in the interface are measured or sampled, preferably using pressure transducers and a pneumotachometer coupled to a personal computer, to obtain pressure and flow data characteristic of the patient'"'"'s airway. The pressure and flow data are converted to the frequency domain using Fourier transform or cross-power spectrum techniques in the personal computer. A function of the processed pressure and flow data is obtained to determine an index of airway impedance or degree of airway obstruction.
77 Citations
16 Claims
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1. A method of determining the airway impedance of a patient comprising the steps of:
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supplying breathable gas to the patient'"'"'s airways with an interface; applying a selected audio-frequency oscillation component to a pressure of the breathable gas; measuring pressure and flow of the breathable gas in the interface to obtain pressure and flow data characteristic of the patient'"'"'s airway; converting the pressure and flow data to the frequency domain; and obtaining a mathematical function of the processed pressure and flow data to determine an index of airway impedance or degree of airway obstruction. - View Dependent Claims (2, 3, 4, 5, 6)
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7. A method of determining the airway impedance or degree of airway obstruction of a patient comprising the steps of:
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supplying breathable gas to the patient'"'"'s airways with an interface; applying a selected audio-frequency oscillation component to a pressure of the breathable gas; sampling pressure and flow of the breathable gas in the interface to obtain pressure and flow data characteristic of the patient'"'"'s airway; converting the sampled pressure and flow data to the frequency domain; processing the converted pressure and flow data to eliminate data having indicia of unreliability; and obtaining a mathematical function of the processed pressure and flow data to determine an index of airway impedance or degree of airway obstruction. - View Dependent Claims (8, 9, 10, 11)
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12. A method of determining the airway impedance or degree of airway obstruction of a patient comprising the steps of:
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supplying breathable gas to the patient'"'"'s airways with an interface; applying a selected audio frequency oscillation component of a selected frequency to the breathable gas; measuring pressure and flow of the breathable gas in the interface to obtain pressure and flow data characteristic of the patient'"'"'s airway; converting the pressure and flow data to the frequency domain; discarding converted pressure and flow data that have indicia of inaccuracy; and dividing the pressure data by the corresponding flow data to obtain an airway impedance or degree of airway obstruction value; and obtaining a mean impedance or degree of airway obstruction from the airway impedance or degree of airway obstruction values. - View Dependent Claims (13, 14, 15)
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16. An apparatus for determining the airway impedance or degree of airway obstruction of a patient comprising:
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an interface adapted to be coupled to the patient'"'"'s airways to supply a breathable gas; means for applying a selected audio-frequency oscillation component to a pressure of the breathable gas; at least one sensor in the interface to measure pressure and flow of the breathable gas in the interface and obtain pressure and flow data characteristic of the patient'"'"'s airway; and a processor coupled to the sensor to convert the pressure and flow data to the frequency domain and to obtain a mathematical function of the processed pressure and flow data to determine an index of airway impedance or degree of airway obstruction.
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Specification