Forced oscillation technique based lung function testing
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Publication Number
US-11357421-B2
Publication Date
2022-06-14
Expiration Date
Abstract
An apparatus for patient's lung function testing using forced oscillation technique is described. The apparatus includes a sub-woofer configured to generate a pressure wave. The apparatus further includes a waveguide configured to direct the generated pressure wave to be introduced into airflow towards the patient's lung. The apparatus includes a pressure transducer configured to measure a change in pressure of the airflow and one or more flow transducers configured to measure a change in flowrate of the airflow, in response to the pressure wave introduced into the airflow. The apparatus includes a computing unit configured to determine a mechanical impedance of the patient's lung based on the measured change in pressure and flowrate of the airflow.
Core Innovation
The invention is a portable forced oscillation lung testing apparatus/system that introduces forced pressure waves into airflow towards a patient's lung through a mouthpiece, using a sub-woofer signal generator and a waveguide. The sub-woofer generates multiple discrete pressure waves of different frequencies while providing a different amount of power to each individual frequency. The waveguide directs the generated pressure waves toward the mouthpiece to be introduced into airflow without obstructing the waveguide path.
The apparatus measures a change in pressure of the airflow in response to the pressure waves using a pressure transducer, and measures a change in flowrate of the airflow in response to the pressure waves using one or more flow transducers. The computing/circuitry determines a mechanical impedance of the patient's lung based on the measured change in pressure and flowrate. The described implementation supports optionally using a pressure transducer implemented as a MEMS-based transducer and using ultrasonic flow transducers to measure flowrate changes.
The described system addresses low-frequency size/power challenges for the generated discrete frequencies by using small sub-woofers with frequency-specific power control for a flatter 3–50 Hz response. It also includes waveguide/mechanical aspects to support airflow introduction and sensing, and includes coherence-based validity checks and optionally calibration and filtering used with impedance estimation. The described arrangement can include a transmitter to send signals to a remote mobile device for impedance computation/display and user feedback.
Claims Coverage
The provided claim set includes three independent claims (apparatus, system, and method). Across these independent claims, there are three core inventive elements: generating multiple discrete frequency pressure waves with frequency-specific power, directing the waves through a waveguide/superimposition onto airflow, and determining lung mechanical impedance from measured pressure and flowrate changes via transducers and circuitry.
Portable forced-oscillation lung testing apparatus with frequency-specific pressure wave generation and impedance determination
An apparatus including a housing and a mouthpiece configured to allow a patient to inhale and exhale air, a sub-woofer disposed within the housing configured to generate multiple discrete pressure waves of different frequencies and provide a different amount of power to each individual frequency, a waveguide coupled to the sub-woofer and configured to direct the generated pressure waves toward the mouthpiece to be introduced into airflow towards the patient's lung, a pressure transducer measuring a change in pressure of the airflow in response to the pressure waves, one or more flow transducers measuring a change in flowrate of the airflow in response to the pressure waves, and circuitry configured to determine a mechanical impedance of the patient's lung based on the measured change in pressure and flowrate.
Forced-oscillation lung testing system with discrete frequency waves, transducer measurements, and impedance circuitry
A system including a sub-woofer configured to generate multiple discrete pressure waves of different frequencies and provide a different amount of power to each individual frequency, a waveguide configured to direct the generated pressure waves to be introduced into airflow towards the patient's lung, a pressure transducer measuring a change in pressure of the airflow in response to the pressure waves, one or more flow transducers measuring a change in flowrate of the airflow in response to the pressure waves, and circuitry configured to determine a mechanical impedance of the patient's lung based on the measured change in pressure and flowrate.
Forced-oscillation lung testing method using discrete frequency waves and impedance determination from pressure and flow
A method including generating via a sub-woofer multiple discrete pressure waves of different frequencies, providing via the sub-woofer a different amount of power to each individual frequency, superimposing the generated pressure waves with airflow towards the patient's lung, measuring via a pressure transducer a change in pressure of the airflow in response to the pressure waves, measuring via one or more flow transducers a change in flowrate of the airflow in response to the pressure waves, and determining a mechanical impedance of the patient's lung based on the measured change in pressure and flowrate.
The independent claims consistently require forced oscillation lung function testing in which multiple discrete pressure waves with frequency-specific power are introduced into patient airflow, pressure and flowrate changes are measured by transducers, and lung mechanical impedance is determined from those measurements by circuitry.
Stated Advantages
Not explicitly described in patent.
Documented Applications
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