Pressure and oxygen saturation catheter

• US 4,730,622 A
• Filed: 08/12/1986
• Issued: 03/15/1988
• Est. Priority Date: 07/01/1986
• Status: Expired due to Term

• Current Assignee: Cordis Corporation (Cardinal Health, Inc.)
• Original Assignee: Cordis Corporation (Cardinal Health, Inc.)
• Inventors: Cohen, Donald M.
• Primary Examiner(s): Kamm, William E.
• Assistant Examiner(s): Hanley, John C.
• Application Number:
  US06/895,898
• Time in Patent Office: 581 Days
• Field of Search: 128/748, 128/667, 128/673, 128/675, 128/634, 73/705, 350/96.32, 350/96.33, 250/231 P
• US Class Current: 600/480
• CPC Class Codes: A61B 5/02154 by optical transmission
• CPC Class Codes: A61B 5/02158 provided with two or more sensor elements
• CPC Class Codes: A61B 5/0261 using optical means, e.g. infrared light
• CPC Class Codes: G01L 11/02 by optical means
• CPC Class Codes: G01L 9/0097 using photoelectric means

Abstract

Apparatus is provided for simultaneously measuring the oxygen content in blood as well as blood pressure at one or more sites within a body cavity or blood vessel. An elongated optical fiber is located within a catheter capable of being inserted into a body cavity. The distal end of the catheter contains a filter covering an end hole so that light may be transmitted through the filter at wavelengths in the red and infrared region while reflecting light of other wavelengths. This permits measurement of the oxygen content of blood. The optical fiber is coaxially surrounded by cladding means essentially throughout its length and is uncladded for at least a portion of its length near the distal end thereof. The catheter carries a pressure transducer associated with the uncladded core portion. The pressure transducer includes a flexible transducer member having an irregular surface facing the uncladded core portion for making surface area contact therewith so that the contacting surface area varies with applied pressure acting transversely of the catheter.

Claims

1. Apparatus for use in measuring the degree of oxygen saturation in blood while simultaneously measuring blood pressure and comprising:

an elongated tubular catheter having a proximal end and a distal end with the latter being adapted to be inserted into a blood vessel within a body;

an elongated optical fiber member carried within said catheter and extending throughout the length thereof, said optical fiber member having a light transmitting core coaxially surrounded by cladding means essentially throughout its length, said core being uncladded for at least a portion of its length proximate to the distal end thereof;

filter means located at the distal end of said catheter and positioned forwardly of the distal end of said optical fiber member to receive light therefrom, said filter means being transmissive to light greater than that of a wavelength W, in the red and infrared wavelength region, and reflecting light at wavelengths less than wavelength W so that light of longer wavelengths may be transmitted through said filter means into blood containing both oxygenated and unoxygenated blood and be reflected therefrom back into the distal end of said catheter; and

said catheter having at least one side port located adjacent the distal end thereof while proximal of said filter means and in registry with a said uncladded portion of said core, pressure transducer means located in said side port including a flexible transducer member having a pitted surface facing said uncladded core portion and making surface area contact therewith such that the contacting surface area varies with pressure applied to said transducer member acting transversely thereof, said transducer member being constructed of material exhibiting a greater index of refraction than said cladding means so that the intensity of light passing through said core proximate to said transducer means is modulated in its intensity as a function of said pressure.

2. Apparatus as set forth in claim 1 wherein said filter means transmits light having a wavelength on the order of at least 800 nanometers to approximatey 950 nanometers.

3. Apparatus as set forth in claim 1 including means for supplying light into the proximal end of said optical fiber member with said light being over a broad band including that beyond wavelength W and in the red and infrared wavelength region, and detecting means for receiving light exiting from said proximal end, said detecting means including means for detecting the amount of light exiting at wavelengths W_A and W_B, both greater than wavelength W, and providing an output indication in dependence thereon representative of the degree of oxygen saturation in the blood.

4. Apparatus as set forth in claim 3 wherein said detecting means includes means for determining the ratio of the amount of light exiting at wavelength W_A to that at wavelength W_B.

5. Apparatus as set forth in claim 4 wherein wavelength W_A is on the order of 805 nanometers and wherein wavelength W_B is on the order of 930 nanometers.

6. Apparatus as set forth in claim 3 wherein said pressure transducer means includes light wavelength dependent means for modulating the intensity of light passing through said core proximate to said transducer means at a particular wavelength as a function of said pressure.

7. Apparatus as set forth in claim 6 wherein said catheter means includes a plurality of said side ports longitudinally spaced along its length adjacent the distal end thereof and wherein each of said side ports carries a said pressure transducer means for simultaneously measuring blood pressure at different sites within the said blood vessel whereby said apparatus serves to simultaneously measure blood pressure at multiple sites, while also measuring the degree of oxygen saturation in the blood, each said transducer means includes light wavelength dependent means for modulating light at a particular wavelength different from that at said other transducer means.

8. Apparatus as set forth in claim 7 wherein each said transducer means includes a transducer filter means or passing light within one wavelength range less than wavelength W while reflect light of other wavelengths.

9. Apparatus as set forth in claim 8 wherein said transducer filter means is interposed between a said uncladded core portion and a said transducer member so that only light passed by said transducer filter means is modulated by said transducer member as a function of said pressure.

10. Apparatus as set forth in claim 9 wherein each said transducer filter means exhibits a different index of refraction with each being greater than that of the index of refraction of said cladding means and wherein each said transducer member exhibits an index of refraction greater than that of the associated said transducer filter means.

11. Apparatus as set forth in claim 10 wherein said detecting means includes means for detecting the amount of light in each of said wavelengths below said wavelength W for simultaneously providing a corresponding plurality of output indications representing the pressure acting on each of said transducer members.

12. Apparatus as set forth in claim 8 wherein each said transducer member has an outer surface and each said transducer filter means is located adjacent the outer surface of a said transducer member with each transducer member being constructed of optically transparent material so that light from a said uncladded core portion passes into said transducer member and only light within a given wavelength range is absorbed by said transducer filter means.

13. Apparatus as set forth in claim 12 wherein said detecting means includes means for detecting the difference in the intensity of light transmitted into and received from said proximal end at each of said wavelengths below said wavelength W and simultaneously providing output indications of the pressure acting on each of said transducer members as a function of said detected differences.

14. Apparatus as set forth in claim 7 wherein each said transducer member is doped with a fluorescent dye, said transducer members at the different transducer menas being doped with different fluorescent dyes so that when excited by light each will fluoresce and emit light at a different wavelength such that the emission level at a given wavelength associated with a specific transducer means varies in dependence upon pressure applied to that transducer means.

15. Apparatus as set forth in claim 14 wherein means for supplying light into the proximal end of said optical fiber member includes means for supplying light within a waveband including wavelengths different than that of the emission wavelengths of each of said transducer means, and said detecting means including means for detecting the amount of light at each of said emission wavelengths for simultaneously providing output indications of the pressure acting on each of said transducer means.