Implantable tissue ischemia sensor

• US 20070027371A1
• Filed: 07/29/2005
• Published: 02/01/2007
• Est. Priority Date: 07/29/2005
• Status: Active Grant

• Current Assignee: JB IP Acquisitions LLC
• Original Assignee: Spectros Corporation (AliphCom Corp.)
• Inventors: Fierro, Michael, Parachikov, Ilian, Benaron, David
• Granted Patent: US 7,813,778 B2
• Time in Patent Office: Days
• US Class Current: 600/310
• CPC Class Codes: A61B 5/0031 Implanted circuitry
• CPC Class Codes: A61B 5/0261 using optical means, e.g. infrared light
• 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 5/412 Detecting or monitoring sepsis

Abstract

An implantable ischemia detection system in which a white LED (105) produces a continuous, visible, broadband light illuminating a target site (125). Light backscattered by the target is collected by a sensor (155), allowing for an index of ischemia to be determined, and subsequently transmitted by a sending unit (167). Power is provided by an internal power source (179). The entire implantable device is encapsulated by a biocompatible shell (102) to add long-term safety with regard to implantation.

Claims

1. An implantable device comprising:

a light source for illuminating a target with light;

a sensor configured so as to detect light backscattered from said target onto said sensor and provide an output signal that is a direct function of the presence or degree of ischemia;

a sending unit for receiving the output signal and transmitting said output signal;

a power source configured to supply energy to said sensor, said source, and said sending unit; and

an exterior shell enclosing said power source, light source, sensor and sending unit configured so as to be biocompatible with respect to implantation.

2. The implantable device of claim 1, wherein said light source is a broadband white LED.

3. The implantable device of claim 1, wherein said sensor is a linear CCD configured so as to be wavelength sensitive.

4. The implantable device of claim 3, wherein said output signal is a function of a measure selected from at least one of a list of measures comprising tissue capillary hemoglobin saturation, cellular myoglobin saturation, and intracellular mitochondrial cytochrome saturation.

5. The implantable device of claim 3, wherein said output signal is generated using differential spectroscopy.

6. The implantable device of claim 1, wherein said power source is an inductive coil for receiving power.

7. The implantable device of claim 1, wherein said sending unit is comprised of any one or more of an RF transmitter, an RFID chip, or an optical fiber.

8. The implantable device of claim 1 wherein said external shell is a fully-sealed biocompatible shell for implantation in an organ or tissue.

9. The implantable device of claim 1 wherein said external shell is a swallowable capsule for passage through the gastrointestinal system.

10. The method of claim 8 wherein said measure of tissue ischemia is a function selected from the list of functions comprising impending risk of tissue death, impending risk of organ rejection, cardiac function, treatment efficacy for arterial or venous vascular disease, risk of renal damage, risk of brain injury, risk of colon death, risk of limb amputation, risk of ulcer healing, or risk of critical limb ischemia.

13. The implantable device of claim 1, wherein said sending unit is directly coupled to an implanted pacemaker, for the purpose of real time feedback.

11. A method of monitoring or detecting tissue ischemia in a living tissue comprising the steps of:

(a) encapsulating and implanting a light emitting and detecting devices at a target site;

(b) illuminating the site with visible light illumination from the emitting device;

(c) detecting light returning from the site using the detecting device;

(d) determining a measure that is a function of tissue ischemia based upon the detected light; and

(e) transmitting the determined measure.

12. An implantable device comprising:

(a) a white LED for illuminating a target with light;

(b) a wavelength-resolved linear CCD configured so as to detect light backscattered from said target onto said CCD;

(c) a sensor configured so as to determine, based upon said light detected by said sensor, an output signal that is a function of the presence or degree of ischemia;

(d) an RF transmitter for receiving and transmitting said output signal;

(e) a an inductive coil for receiving power configured to supply energy to said LED, said CCD, and said RF transmitter; and

(f) an exterior shell configured so as to be biocompatible with respect to implantation housing said LED, CCD, sensor, RF transmitter and inductive coil.