Optical sensing catheter system

• US 7,519,407 B2
• Filed: 02/25/2007
• Issued: 04/14/2009
• Est. Priority Date: 02/21/2006
• Status: Expired due to Fees

• Current Assignee: Physical Logic AG
• Original Assignee: Physical Logic AG
• Inventors: Axelrod, Noel, Ofek, Eran, Peleg, Asaf
• Primary Examiner(s): WINAKUR, ERIC FRANK
• Application Number:
  US11/678,613
• Publication Number:
  US 20070203414A1
• Time in Patent Office: 779 Days
• Field of Search: 600/310, 600/322, 600/323, 600/341, 600/342, 385/12, 385/13
• US Class Current: 600/341
• CPC Class Codes: A61B 2562/0233 Special features of optical sensors or probes classified in A61B5/00
• CPC Class Codes: A61B 2562/043 in a linear array
• CPC Class Codes: A61B 2562/223 Optical cables therefor
• CPC Class Codes: A61B 5/14542 for measuring blood gases A61B5/14551 takes precedence
• CPC Class Codes: A61B 5/1459 invasive, e.g. introduced into the body by a catheter A61B5/1464 takes precedence
• CPC Class Codes: A61B 5/6852 Catheters
• CPC Class Codes: G02B 6/29328 Diffractive elements operating in reflection
• CPC Class Codes: G02B 6/29367 Zigzag path within a transparent optical block, e.g. filter deposited on an etalon, glass plate, wedge acting as a stable spacer
• CPC Class Codes: G02B 6/43 Arrangements comprising a plurality of opto-electronic elements and associated optical interconnections

Abstract

An optical sensing catheter system for physiological measurements of vascular or arterial parameters at plurality of location deploys wavelength division multiplexing in a common optical fiber to communicate with each optical sensor. The sensors are preferably passive planar waveguide type devices disposed to interact with the environment external to the catheter or other medical device.

Claims

1. An implantable medical device comprising:

a) an elongated sheath,

b) a waveguide disposed within said sheath,

c) at least one multi-wavelength light source for illuminating said waveguide,

d) at least one multi-wavelength photo-detection means to receive light from said waveguide,

e) two or more optical sensors in optical communication with said light source and photo-detection means via said waveguide wherein each sensor is operative to modulate the propagation of light of a different wavelength in said waveguide wherein at least one sensor is for measuring the concentration of oxygenated and deoxygenated hemoglobin by direct contact with blood and comprises;

i) a sensor waveguide having a planar support as a cladding on a first surface with a second surface parallel to the plane of the first surface and capable of being exposed directly to a fluid,

ii) a reflective surface orthogonal to the direction of propagation of light within the sensor waveguide.

2. A device according to claim 1 wherein the evanescent light exiting the sensor waveguide is capable of substantially penetrating into red blood cells.

3. A device according to claim 1 wherein the sensor waveguide has a refractive index (n) that is less than 1.45 at the absorption bands of Hb and HbO2.

4. A device according to claim 1 wherein the sensor waveguide has a refractive index (n) that is between about 1.375 and about 1.45 at the absorption bands of Hb and HbO2.

5. A device according to claim 1 wherein said multi-wavelength light source is a pig-tailed laser.

6. A device according to claim 5 wherein said sheath is a catheter lead.

7. A device according to claim 1 wherein said sheath is a catheter lead.

8. A device according to claim 7 wherein said multi-wavelength light source is a pig-tailed laser.

9. An implantable medical device comprising:

a) an elongated sheath,

b) a waveguide disposed within said sheath,

c) at least one multi-wavelength light source for illuminating said waveguide,

d) at least one multi-wavelength photo-detection means to receive light from said waveguide,

e) one or more optical sensors in optical communication with said light source and photo-detection means via said waveguide wherein each sensor is operative to modulate the propagation of light of a different wavelength in said waveguide wherein at least one sensor is for measuring blood pressure and comprises at least one Mach-Zehnder Interferometer (MZI) in optical communication with said waveguide and is disposed with a single arm in tactile communication with the environment external to said sheath and further comprising another optical sensor for measuring the concentration of oxygenated and deoxygenated hemoglobin by direct contact with blood, which comprises;

i) a sensor waveguide having a planar support as a cladding on a first surface with a second surface parallel to the plane of the first surface and capable of being exposed directly to a fluid,

ii) a reflective surface orthogonal to the direction of propagation of light within the sensor waveguide.

10. A device according to claim 9 wherein the evanescent light exiting the sensor waveguide is capable of substantially penetrating into red blood cells.

11. A device according to claim 10 wherein said sheath is a catheter lead.

12. A device according to claim 9 wherein the sensor waveguide has a refractive index (n) that is less than 1.45 at the absorption bands of Hb and HbO₂.

13. A device according to claim 9 wherein the sensor waveguide has a refractive index (n) that is between about 1.375 and about 1.45 at the absorption bands of Hb and HbO₂.

14. A device according to claim 13 wherein said sheath is a catheter lead.