Infrasonic stethoscope for monitoring physiological processes
Inventors
Shams, Qamar A. • Zuckerwar, Allan J. • Dimarcantonio, Albert L.
Assignees
National Aeronautics and Space Administration NASA
Publication Number
US-9445779-B2
Publication Date
2016-09-20
Expiration Date
2035-03-16
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Abstract
An infrasonic stethoscope for monitoring physiological processes of a patient includes a microphone capable of detecting acoustic signals in the audible frequency bandwidth and in the infrasonic bandwidth (0.03 to 1000 Hertz), a body coupler attached to the body at a first opening in the microphone, a flexible tube attached to the body at a second opening in the microphone, and an earpiece attached to the flexible tube. The body coupler is capable of engagement with a patient to transmit sounds from the person, to the microphone and then to the earpiece.
Core Innovation
The invention is an infrasonic stethoscope, also called an infrascope, used for monitoring physiological processes of a patient by detecting acoustic signals within the audible frequency bandwidth and the infrasonic bandwidth from 0.03 Hertz to 1000 Hertz. It incorporates a microphone with a body having two spaced-apart openings to which a body coupler and a flexible tube with an earpiece are attached, enabling engagement with the patient to transmit sounds to the microphone and then to the earpiece.
The microphone features a membrane and backplate configuration forming a capacitor, with a preamplifier to measure capacitance changes due to physiological sounds. The microphone design includes elements to provide damping and acoustic resistance, enabling detection of low-frequency infrasonic signals with high sensitivity and a flat frequency response. The body coupler forms an air-tight seal and may be configured for external or internal fetal monitoring through attachment to a catheter.
The problem addressed arises from limitations of existing stethoscopes and physiological monitors, which primarily detect audible frequency signals and are generally incapable of detecting valuable low-frequency infrasonic signals below 20 Hertz, which can provide important physiological information, especially heart sounds and fetal monitoring data. The invention overcomes issues such as signal attenuation in tissues at higher frequencies and the inability to capture low-frequency sounds that may contribute to diagnosing cardiovascular diseases and fetal conditions.
Claims Coverage
The patent includes one independent claim defining the infrasonic stethoscope apparatus with several main inventive features.
Microphone capable of detecting infrasonic and audible frequencies
A microphone capable of detecting acoustic signals in an entire frequency range from 0.03 Hertz to 1000 Hertz with a body having first and second spaced apart openings.
Body coupler forming an air-tight seal with the microphone
A body coupler attached to the first opening of the microphone body to form a substantially air-tight seal and capable of engagement with the patient to transmit physiological sounds.
Flexible tube and earpiece for sound transmission
A flexible tube attached to the second opening of the microphone body with an earpiece attached to the flexible tube for listening to transmitted sounds.
The inventive features focus on the structure of the infrasonic stethoscope comprising a specialized microphone capable of infrasonic signal detection, an air-tight body coupler designed for patient engagement, and a sound transmission system using a flexible tube and earpiece. These features together establish the infrasonic stethoscope's capability to detect and transmit low-frequency physiological signals.
Stated Advantages
Enables medical personnel to monitor both audible and infrasonic bandwidths for enhanced analysis of physiological processes.
Provides high quality, low attenuation signal detection with better signal-to-noise ratio, particularly for low-frequency sounds valuable for cardiac and fetal monitoring.
Enables real-time wireless transmission of physiological process signals to remote locations for timely diagnosis and monitoring.
Is a relatively inexpensive tool useful for early-stage diagnosis of abnormalities and can be used in ambulances and various medical environments.
Documented Applications
Cardiac monitoring by detecting heart sounds including S1, S2, S3, and S4 components.
External fetal monitoring by placing the body coupler against the abdomen to track fetal heart rate and uterine contractions.
Internal fetal monitoring using a catheter inserted into the bladder near the uterus to detect fetal heart sounds and contractions.
Stress phonocardiography testing to monitor heart problems that occur during physical activity.
Doppler phonocardiography to measure blood flow within the heart using paired infrasonic stethoscopes.
Biometric identification by extracting heartbeat signatures remotely.
Polygraph monitoring of cardiovascular, electrodermal, and respiratory physiological processes through infrasonic signals for response detection.
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