Acoustic sensor assembly
Inventors
Telfort, Valery G. • Pudar, Predrag • Dimitrov, Dimitar • Trang, Phi • Al-Ali, Ammar
Assignees
Publication Number
US-12232905-B2
Publication Date
2025-02-25
Expiration Date
2029-12-21
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Abstract
An acoustic sensor is configured to provide accurate and robust measurement of bodily sounds under a variety of conditions, such as in noisy environments or in situations in which stress, strain, or movement may be imparted onto a sensor with respect to a patient. Embodiments of the sensor provide a conformable electrical shielding, as well as improved acoustic and mechanical coupling between the sensor and the measurement site.
Core Innovation
The invention provides an acoustic sensor assembly designed to accurately and robustly measure bodily sounds under diverse conditions, including noisy environments and scenarios involving stress, strain, or movement applied to the sensor relative to a patient. The sensor assembly comprises a housing with a spacing element, a piezoelectric element coupled to the housing, and an at least partially flexible acoustic coupler configured for direct tissue contact. The coupler includes an outer protrusion on its exterior surface and is constructed to apply pressure to the piezo element through a coupling element, thereby biasing the piezo element in tension.
The problem addressed by this invention arises from the limitations of existing piezoelectric membranes and sensors used for non-invasive detection of biological sounds, which can suffer from reduced reliability and accuracy, especially in environments with significant electrical noise or where sensor attachment is challenged by patient movement. Prior piezoelectric sensors were limited in their ability to maintain robust coupling with the measurement site and to provide effective immunity to external noise or interference, leading to risks of signal degradation and poor measurement quality.
To solve these challenges, the disclosed sensor assembly introduces a conformal electrical shielding barrier, such as a Faraday cage formed by first and second electrical shielding layers that encompass the piezoelectric sensing element, actively conforming to its changing surface shape. The assembly also features improved mechanical and acoustic coupling via the acoustic coupler and coupling element, which can include elastomeric or gel components to match acoustic impedance and enhance pressure distribution, as well as electrical isolation from the patient. Attachment elements, including elastic portions and specialized tape portions, ensure secure sensor positioning and predetermined force application, maintaining sensor performance during movement or external perturbation.
Claims Coverage
The patent claims several inventive features centered around the structure, coupling, isolation, attachment mechanism, and operation of the acoustic sensor assembly.
Flexible acoustic coupler with outer protrusion and tensioned piezo element
The acoustic device assembly includes a housing with a spacing element and a piezo element comprising piezoelectric material. An at least partially flexible acoustic coupler is coupled to the housing and has a first portion configured to contact the user's tissue. This portion has an outer protrusion on the outside surface of the acoustic coupler. The piezo element is spaced from the acoustic coupler by the spacing element and coupled to the acoustic coupler by a coupling element that applies pressure to bias the piezo element in tension.
Acoustic coupler transmitting vibrations and providing electrical isolation
The acoustic coupler is constructed to communicate acoustic vibrations from the tissue to the piezo element via the coupling element. Additionally, the coupler electrically isolates the piezo element from the user when the assembly is attached, with the coupler optionally being comprised of an elastomer.
Elastic portion for predetermined force and attachment
An elastic portion is attached to the housing, extending at least partially beyond opposite sides of the housing. This elastic portion is configured to apply a predetermined force to the housing through stretching, ensuring the assembly is pressed against the tissue of the user when attached. The elastic portion may at least partially surround the housing and can be permanently affixed. It may also be attached to a tape portion and/or to the topside of the tape portion and housing, with attachment at a middle point, and is inclined with respect to the tape portion when attached.
Method of detecting and converting acoustic vibrations to electrical signals
The method involves detecting acoustic vibrations using the acoustic device assembly, transmitting the vibrations to the piezo element via the acoustic coupler and coupling element, and converting these vibrations to electrical signals, which are then output. The method may further include processing the electrical signal by an acoustic monitor to determine one or more physiological parameter measurements of the user, such as heart rate, heart sounds, respiratory rate, expiratory flow, tidal volume, minute volume, apnea duration, breath sounds, riles, rhonchi, stridor, or changes in breath sounds.
The claimed inventive features encompass a robust assembly structure with a tensioned piezo element, flexible acoustic coupler, specialized attachment and isolation mechanisms, and defined methods for physiological monitoring based on acoustic vibrations.
Stated Advantages
Provides accurate and robust measurement of bodily sounds under a variety of conditions, including noisy environments or during stress, strain, or movement.
Enhanced electrical shielding and noise immunity are achieved by conformable shielding layers forming a Faraday cage around the piezoelectric element.
Improved acoustic and mechanical coupling between the sensor and the measurement site for better signal transmission.
Electrical isolation between the patient and the sensor prevents harmful electrical pathways or ground loops.
Secure and reliable attachment is maintained by elastic portions and tape elements that apply a predetermined force, reducing the risk of detachment during movement.
Attachment mechanism resists peel-off and maintains consistency even with patient skin movement or stretching.
Decoupling of sensor from cable movement reduces noise artifacts in the measured signal due to cable handling or accidental tugging.
Modular, resposable design allows for disposable and reusable elements, supporting cost-effective and hygienic use.
Documented Applications
Non-invasive measurement of bodily sounds related to physiological parameters in medical patients.
Use in physiological monitoring systems to determine parameters such as respiratory rate, expiratory flow, tidal volume, minute volume, apnea duration, breath sounds, riles, rhonchi, stridor, and changes in breath sounds such as decreased volume or change in airflow.
Monitoring of other physiological sounds, including heart rate (for probe-off detection), heart sounds (S1, S2, S3, S4, murmurs), and changes in heart sounds indicating conditions like fluid overload.
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