Implantable oximetric measurement apparatus and method of use
Embodiments provide an apparatus, system, kit and method for in vivo measurement of blood oxygen saturation (BAS). One embodiment provides an implantable apparatus for measuring BAS comprising a housing, emitter, detector, processor and power source. The housing is configured to be injected through a tissue penetrating device into a target tissue site (TS). The emitter is configured to emit light into the TS to measure BAS, the emitted light having at least one wavelength (LOW) whose absorbance is related to a BAS. The detector is configured to receive light reflected from the TS, detect light at the LOW and generate a detector output signal (DOS) responsive to an intensity of the detected light. The processor is operably coupled to the detector and emitter to send signals to the emitter to emit light and receive the DOS and includes logic for calculating a BAS and generate a signal encoding the BAS.
1. An implantable apparatus for measuring blood oxygen saturation levels in a patient, the apparatus comprising:
a housing having a wall and an interior volume, at least a portion of the housing wall comprising an optically transparent material, the housing having a size, shape and column strength to be injected through and released from a hollow tissue penetrating device into an intramuscular target tissue site beneath a skin of the patient by the application of a force on a proximal end of the housing;
an optical emitter positioned within the housing, the emitter arranged and configured to emit light through the housing wall and into the tissue site to measure a blood oxygen saturation within the tissue site, the emitted light having at least one wavelength whose absorbance is related to a level of blood oxygen saturation;
an optical detector positioned within the housing and arranged to receive light reflected from the tissue site, the optical detector configured to detect light at the at least one wavelength and generate a detector output signal responsive to an intensity of the detected light;
a processor positioned within the housing and operably coupled to the detector and emitter to send signals to the emitter to emit light and receive the detector output signal, the processor including logic for calculating a blood oxygen saturation level using the detector output signal and generating a signal encoding the blood oxygen saturation level and logic to adjust at least of an intensity or wavelength of the emitted light to penetrate a selectable depth into tissue at the target site; and
a power source positioned within the housing for powering at least one of the processor, the emitter or the detector, the power source coupled to at least the processor.
2. The apparatus of claim 1 , wherein the housing has a substantially tubular shape.
3. The apparatus of claim 1 , wherein the tissue penetrating device comprises a syringe.
4. The apparatus of claim 3 , wherein the syringe includes a needle and the housing is configured to be injected into the tissue site through the needle.
5. The apparatus of claim 1 , wherein the optically transparent material comprises glass or an optically transparent polymer.
6. The apparatus of claim 1 , wherein the optically transparent material is positioned in an optical window comprising a portion of the housing wall.
7. The apparatus of claim 1 , wherein the housing includes a coating for reducing tissue adhesion to a housing exterior surface.
8. The apparatus of claim 7 , wherein the coating comprises a corticosteroid or dexamethasone.
9. The apparatus of claim 1 , wherein the power source comprises a portable battery, a lithium ion battery, a capacitor or a super capacitor.
10. The apparatus of claim 1 , further comprising an induction device operably coupled to the power source for recharging the power source using an external electromagnetic signal.
11. The apparatus of claim 10 , wherein the induction device comprises an induction coil.
12. The apparatus of claim 1 , further comprising an RF communication device operably coupled to the processor, the RF communication device configured to generate and transmit an RF signal corresponding to the blood oxygen saturation signal.
13. The apparatus of claim 12 , wherein the RF communication device sends the RF signal responsive to a signal external to the patient's body.
14. The apparatus of claim 12 , wherein the RF communication device is configured to communicate with a portable monitoring device or cell phone.
15. The apparatus of claim 1 , wherein the at least one wavelength comprises at least a first and a second wavelength.
16. The apparatus of claim 15 , wherein the first wave length is in a range of about 600 to about 750 nm.
17. The apparatus of claim 15 , wherein the second wave length is in a range of about 850 to about 1000 nm.
18. The apparatus of claim 1 , wherein the detector comprises a photomultiplier or a charge coupled device.
19. The apparatus of claim 1 , wherein the emitter is configured to emit light which penetrates at least about 1 cm into the tissue site.
20. The apparatus of claim 1 , wherein the emitter is configured to emit light which penetrates at least about 2 cm into the tissue site.
21. The apparatus of claim 1 , wherein the emitter comprises an LED.
22. The apparatus of claim 1 , further comprising:
a modulation device operably coupled to the detector, the modulation device configured to modulate the output signal from the detector into an electrical signal having a frequency.
23. The apparatus of claim 22 , further comprising an RF communication device operably coupled to the modulation device, the RF communication device configured to transmit an RF signal corresponding to the electrical signal.
24. The apparatus of claim 1 , further comprising:
a magnetic hook coupled to the housing for removal of the apparatus from the tissue site by a removal tool containing a magnetized portion.
25. The apparatus of claim 24 , wherein the magnetic hook comprises at least one of a ferrous material or a magnet.
26. The apparatus of claim 1 , wherein the housing includes a biodegradable tissue penetrating attachment.
27. A system for detection of deep vein thrombosis of a patient, the system comprising:
the apparatus of claim 1 ; and
a monitoring device configured to receive an input from the apparatus and process the input into an output for indicating the presence of deep vein thrombosis.
28. The system of claim 27 , wherein the monitoring device includes a display configured to display the output.
29. The system of claim 27 , wherein the output is displayed on a graph.
30. The system of claim 27 , wherein the apparatus wirelessly signals the input to the monitoring device.
31. A kit for detection of deep vein thrombosis of a patient, the kit comprising:
the apparatus of claim 1 ; and
instructions for using the apparatus of claim 1 with a portable device in order to detect deep vein thrombosis.
32. A method for measuring a blood oxygen saturation level, in a patient, the method comprising:
penetrating a hollow tissue penetrating device through a patient's skin to an intramuscular target tissue site;
injecting through the hollow tissue penetrating device to the target tissue site in the patient an apparatus for measuring blood oxygen saturation level, wherein injecting comprises applying a sufficient force on a proximal end of the housing of the apparatus to cause a distal end of the apparatus to penetrate through tissue to reach the target tissue site; and
measuring an oxygen saturation level of the target tissue site using the implanted apparatus, wherein said measuring comprises emitting light into tissue from the implanted apparatus and at least one of an intensity or wavelength of the emitted light are adjusted to penetrate a selectable depth into tissue so as to measure oxygen saturation of tissue at the selectable depth.
33. The apparatus of claim 1 , where a column strength of the housing is in a range of about one to five pounds.
34. The method of claim 32 , where the force applied to the proximal end of the housing is in a range of about one to five pounds.
35. An implantable apparatus for measuring blood oxygen saturation levels in a patient, the apparatus comprising:
a housing having a wall, an interior volume, an atraumatic distal end and a biodegradable tissue penetrating element attached to the atraumatic distal end of the housing so that the atraumatic distal end and the biodegradable distal end can be injected attached together into tissue, at least a portion of the housing wall comprising an optically transparent material, the housing having a size, shape and column strength to be injected through and released from a hollow tissue penetrating device into a target tissue site beneath a skin of the patient by the application of a force on a proximal end of the housing; wherein after release of the housing into tissue, the biodegradable tissue penetrating element degrades at the tissue site to reveal the atraumatic distal end of the housing;
an optical emitter positioned within the housing, the emitter arranged and configured to emit light through the housing wall and into the tissue site to measure a blood oxygen saturation within the tissue site, the emitted light having at least one wavelength whose absorbance is related to a level of blood oxygen saturation;
an optical detector positioned within the housing and arranged to receive light reflected from the tissue site, the optical detector configured to detect light at the at least one wavelength and generate a detector output signal responsive to an intensity of the detected light;
a processor positioned within the housing and operably coupled to the detector and emitter to send signals to the emitter to emit light and receive the detector output signal, the processor including logic for calculating a blood oxygen saturation level using the detector output signal and generating a signal encoding the blood oxygen saturation level; and
a power source positioned within the housing for powering at least one of the processor, the emitter or the detector, the power source coupled to at least the processor.
36. The implantable apparatus of claim 1 , wherein the penetration depth of emitted light into tissue is up to about 3 cm.
37. The implantable apparatus of claim 36 , wherein the penetration depth of emitted light into tissue is up to about 0.5, 1 or 2 cm.
38. An implantable apparatus for measuring blood oxygen saturation levels in a patient, the apparatus comprising:
a housing having a wall and an interior volume, at least a portion of the housing wall comprising an optically transparent material, the housing having a size, shape and column strength to be injected through and released from a hollow tissue penetrating device into an intramuscular tissue site beneath a skin of the patient by the application of a force on a proximal end of the housing;
an optical emitter positioned within the housing, the emitter arranged and configured to emit light through the housing wall and into the tissue site to measure a blood oxygen saturation within the tissue site, the emitted light having at least one wavelength whose absorbance is related to a level of blood oxygen saturation;
an optical detector positioned within the housing and arranged to receive light reflected from the tissue site, the optical detector configured to detect light at the at least one wavelength and generate a detector output signal responsive to an intensity of the detected light; wherein the optical detector and optical emitter are linearly arranged with respect to a length of the housing and recessed below the housing wall so as to produce a selected angle of light incidence and reflection with a target tissue site;
a processor positioned within the housing and operably coupled to the detector and emitter to send signals to the emitter to emit light and receive the detector output signal, the processor including logic for calculating a blood oxygen saturation level using the detector output signal and generating a signal encoding the blood oxygen saturation level; and
a power source positioned within the housing for powering at least one of the processor, the emitter or the detector, the power source coupled to at least the processor.