Device for monitoring cardiovascular signals and fiber optic coupler phonocardio sensor therefor

• US 5,074,309 A
• Filed: 12/04/1989
• Issued: 12/24/1991
• Est. Priority Date: 12/04/1989
• Status: Expired due to Term

• Current Assignee: Mid-America Commercialization Corporation
• Original Assignee: Sperry Marine, Inc. (Northrop Grumman Corporation)
• Inventors: Gerdt, David W.
• Primary Examiner(s): SHUMAKER, STEVEN
• Assistant Examiner(s): Longo, Robin R.
• Application Number:
  US07/444,920
• Time in Patent Office: 750 Days
• Field of Search: 128/701, 128/715, 128/717, 128/691, 128/694, 128/687, 128/721, 73/655, 73/656, 73/603, 73/705, 73/715, 250/227, 250/231 P, 250/227.14, 250/227.28, 250/227.24, 250/231.10, 250/231.19, 350/96.1, 350/96.15
• US Class Current: 600/528
• CPC Class Codes: A61B 5/02433 for infrared radiation
• CPC Class Codes: A61B 5/055 involving electronic [EMR] or nuclear [NMR] magnetic resonance, e.g. magnetic resonance imaging
• CPC Class Codes: A61B 7/04 Electric stethoscopes microphones, acoustic transducers therefor H04R
• CPC Class Codes: G01H 9/004 using fibre optic sensors light guides per se G02B6/00, acousto-optical devices specially adapted for gating or modulating in optical wave guides G02F1/125
• CPC Class Codes: G01P 15/093 by photoelectric pick-up

Abstract

Cardiovascular sounds from a patient'"'"'s body are monitored by placing a fiber optic coupler sensor at an appropriate location on the patient to sense the sounds. The sensor is comprised of all dielectric material having a variable coupler waist region encapsulated in material with index of refraction that varies with applied stress. Stress is induced in the encapsulating material in response to the cardiovascular sounds. Sensor configurations include encapsulating material membranes with curved surfaces to enhance sensitivity.

Claims

1. A fiber optic coupler cardiovascular sound sensor constructed of only dielectric material for use in a non-evasive method of monitoring cardiovascular sounds, including sub-audible sound, without danger of burn or electrical shock hazard to a patient or invading the interior of said patient'"'"'s body, said sensor comprising

a plurality of input optical fibers each having a core, said cores of said optical fibers being merged and fused in a waist region to form a common optical core wherefrom a plurality of output optical fibers emerge, said fiber optic coupler sensor distributing light energy incident to one of said input optical fibers between said plurality of output optical fibers,

a membrane encapsulating said waist region and having a refractive index variable with stress applied thereto such that said incident light energy is distributed between said plurality of output optical fibers as a function of said stress applied, a support member with a cavity and an aperture therein, said aperture extending through said support member to said cavity, said waist region encapsulated in said membrane disposed in said cavity such that said stress applied is to responsive to cardiovascular sounds coupled to said cavity through said support member, said membrane including at least one curved surface so that said membrane has a non-uniform thickness with a thinnest section, said waist region being encapsulated in said membrane so that said waist region extends through said thinnest section, thereby enhancing the sensitivity thereof to said cardiovascular sounds;

a taut film secured across an opening of said aperture, and

means for converting said distributed light energy emerging from said output optical fibers into corresponding electrical signals, thereby monitoring said cardiovascular sounds, including said sub-audible sound, without danger of burn or electrical shock hazard to said patient.

2. The sensor of claim 1 wherein said

taut is plastic film and, said encapsulating material is in intimate contact with said plastic film.

3. The sensor of claim 2 wherein said plastic film comprises polyvinyl chloride.

4. The sensor of claim 1 wherein said encapsulating material comprises silicon rubber.

5. The sensor of claim 1 wherein said encapsulating material comprises RTV-12 silicon rubber.

6. The sensor of claim 1 wherein said encapsulating material comprises a low index optical epoxy.

7. The sensor of claim 1 wherein said encapsulating material comprises a low index polymer.

8. The sensor of claim 1 wherein said encapsulating material comprises a low index resin.

9. The sensor of claim 1 wherein said thinnest section of said membrane is at the center thereof.

10. A fiber optic coupler cardiovascular sound sensor constructed of only dielectric material for use in a non-evasive method of monitoring cardiovascular sounds, including sub-audible sound, without danger of burn or electrical shock hazard to a patient or invading the interior of said patient'"'"'s body, said sensor comprising

a plurality of input optical fibers each having a core, said cores of said optical fibers being merged and fused in a waist region to form a common optical core wherefrom a plurality of output optical fibers emerge, said fiber optic coupler sensor distributing light energy incident to one of said input optical fibers between said plurality of output optical fibers,

a membrane encapsulating said waist region and having a refractive index variable with stress applied thereto such that said incident light energy is distributed between said plurality of output optical fibers as a function of said stress applied,

a support member with a cavity and an aperture therein, said aperture extending through said support member to said cavity, said waist region encapsulated in said membrane disposed in said cavity such that said stress applied is to responsive to cardiovascular sounds coupled to said cavity through said support member, said membrane including at least one curved surface so that said membrane has a non-uniform thickness with a thinnest section, said waist region being encapsulated in said membrane so that said waist region extends through said thinnest section, thereby enhancing the sensitivity thereof to said cardiovascular sounds;

means for converting said distributed light energy emerging from said output optical fibers into corresponding electrical signals, thereby monitoring said cardiovascular sounds, including said sub-audible sound, without danger of burn or electrical shock hazard to said patient.