Blood oxygen monitoring system and a lead therefor
First Claim
1. An implantable cardiac stimulation system comprising:
- a cardiac stimulation lead adapted to be in contact with a patient'"'"'s blood stream and selected cardiac sites, said stimulation lead having at least one electrical conductor; and
a stimulation device comprising;
a processor;
an oxygen monitoring circuit electrically coupled to said at least one electrical conductor and in contact with the patient'"'"'s blood stream, said oxygen monitoring circuit configured to monitor the oxygen concentration of the patient'"'"'s blood;
a cardiac stimulation pulse generator coupled and responsive to the processor and configured to deliver cardiac stimulation pulses via the cardiac stimulation lead to the selected cardiac sites;
an oxygen monitoring pulse generator coupled to the processor and configured to generate a biphasic pulse train for application to the at least one electrical conductor between consecutive cardiac stimulation pulses, the pulse train defining a data frame having a pre-determined number of bits including parameter information bits, wherein upon the occurrence of the biphasic pulse train, the oxygen monitoring circuit interrogates the patient'"'"'s blood during an interval between consecutive cardiac stimulation pulses to measure the blood oxygen concentration utilizing respective ones of the pulse train bits for carrying commands and parameter information between the processor and oxygen monitoring circuit.
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Accused Products
Abstract
An oxygen monitoring system measures the oxygen concentration in a patient'"'"'s blood for use as a physiological control parameter in rate responsive pacing. The oxygen monitoring system includes an oxygen monitoring circuit embedded in a cardiac stimulation lead and monitors the blood oxygen in a patient'"'"'s venous system that passes through and into the lead. The oxygen monitoring circuit includes a working electrode, a counter electrode, a reference electrode and an IC chip electrically interconnected between the electrodes and programmed to carry out an oxygen concentration measuring process. Oxygen surrounding the electrodes causes current to flow between the electrodes and the IC chip varies the value of current generated by a current source coupled between the working electrode and counter electrode in a manner to maintain the voltage between the working electrode and reference electrode at a preselected value. The variation of the current source value is a direct measure of the blood oxygen concentration. The oxygen monitoring circuit may comprise an IC chip mounted on one side of a substrate and on the reverse side of which are mounted the electrodes or an IC chip(s) upon which the electrodes are directly mounted. Furthermore, the IC chip, with appropriate insulation may be used in place of the substrate. At least two insulated IC chips may be used, for example in a back to back arrangement, for increased overall sensitivity or redundancy.
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Citations
34 Claims
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1. An implantable cardiac stimulation system comprising:
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a cardiac stimulation lead adapted to be in contact with a patient'"'"'s blood stream and selected cardiac sites, said stimulation lead having at least one electrical conductor; and a stimulation device comprising; a processor; an oxygen monitoring circuit electrically coupled to said at least one electrical conductor and in contact with the patient'"'"'s blood stream, said oxygen monitoring circuit configured to monitor the oxygen concentration of the patient'"'"'s blood; a cardiac stimulation pulse generator coupled and responsive to the processor and configured to deliver cardiac stimulation pulses via the cardiac stimulation lead to the selected cardiac sites; an oxygen monitoring pulse generator coupled to the processor and configured to generate a biphasic pulse train for application to the at least one electrical conductor between consecutive cardiac stimulation pulses, the pulse train defining a data frame having a pre-determined number of bits including parameter information bits, wherein upon the occurrence of the biphasic pulse train, the oxygen monitoring circuit interrogates the patient'"'"'s blood during an interval between consecutive cardiac stimulation pulses to measure the blood oxygen concentration utilizing respective ones of the pulse train bits for carrying commands and parameter information between the processor and oxygen monitoring circuit. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12)
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13. A cardiac stimulation lead for use with a cardiac stimulation device, the device comprising, a processor, a cardiac stimulation pulse generator coupled and responsive to the processor and configured to deliver cardiac stimulation pulses via the cardiac stimulation lead to selected cardiac sites, an oxygen monitoring pulse generator coupled to the processor and configured to generate a biphasic digital pulse train defining a data frame for application to the cardiac stimulation lead between consecutive cardiac stimulation pulses, the biphasic pulse train having a pre-determined number of bits including parameter information bits, the stimulation lead comprising:
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at least one electrical conductor, said lead adapted to be in contact with a patient'"'"'s blood stream and selected cardiac sites; and an oxygen monitoring circuit electrically coupled to said at least one electrical conductor and adapted to be in contact with the patient'"'"'s blood stream, said oxygen monitoring circuit configured to monitor the oxygen concentration of the patient'"'"'s blood, wherein upon the occurrence of the biphasic pulse train, the oxygen monitoring circuit interrogates the patient'"'"'s blood during an interval between consecutive cardiac stimulation pulses to measure the blood oxygen concentration utilizing respective ones of the pulse train bits for carrying commands and parameter information between the processor and oxygen monitoring circuit. - View Dependent Claims (14, 15, 16, 17, 18, 19, 20, 21, 22)
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23. A cardiac stimulation lead for use with a cardiac stimulation device, the device comprising, a processor, a cardiac stimulation pulse generator coupled and responsive to the processor and configured to deliver cardiac stimulation pulses via the cardiac stimulation lead to selected cardiac sites, an oxygen monitoring pulse generator coupled to the processor and configured to generate a biphasic pulse train for application to the cardiac stimulation lead between consecutive cardiac stimulation pulses, the stimulation lead comprising:
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at least one electrical conductor, said lead adapted to be in contact with a patient'"'"'s blood stream and selected cardiac sites; and an oxygen monitoring circuit electrically coupled to said at least one electrical conductor and adapted to be in contact with the patient'"'"'s blood stream, said oxygen monitoring circuit configured to monitor the oxygen concentration of the patient'"'"'s blood, wherein the oxygen monitoring circuit interrogates the patient'"'"'s blood during an interval between consecutive cardiac stimulation pulses to measure the blood oxygen concentration utilizing the biphasic pulse train for carrying commands and parameter information between the processor and oxygen monitoring circuit.
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24. A cardiac stimulation lead for use with a cardiac stimulation device, the device comprising, a processor, a cardiac stimulation pulse generator coupled and responsive to the processor and configured to deliver cardiac stimulation pulses via the cardiac stimulation lead to selected cardiac sites, an oxygen monitoring pulse generator coupled to the processor and configured to generate a biphasic pulse train for application to the cardiac stimulation lead, the stimulation lead comprising:
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at least one electrical conductor, said lead adapted to be in contact with a patient'"'"'s blood stream and selected cardiac sites; and an oxygen monitoring circuit electrically coupled to said at least one electrical conductor and adapted to be in contact with the patient'"'"'s blood stream, said oxygen monitoring circuit configured to monitor the oxygen concentration of the patient'"'"'s blood, wherein the oxygen monitoring circuit interrogates the patient'"'"'s blood to measure the blood oxygen concentration utilizing the biphasic pulse train for carrying commands and parameter information between the processor and oxygen monitoring circuit, wherein the oxygen monitoring circuit comprises; a working electrode, a counter electrode and a reference electrode; an integrated circuit chip electrically coupled to said electrodes and programmed to undertake an oxygen concentration measurement process; a current source controlled by said integrated circuit chip and coupled between the working electrode and the counter electrode and configured to supply current between the working and counter electrodes; a voltage monitor arranged to detect the voltage across the reference electrode and working electrode;
wherein the integrated circuit chip is programmed to control the level of current supplied by the current source and to monitor the detected voltage such that upon exposure of the electrodes to varying levels of oxygen concentration, varying levels of current are caused to flow between the working electrode and counter electrode and wherein the detected voltage is caused to change and further wherein the integrated circuit chip causes the current source to generate a current of a magnitude to return the detected voltage to a preselected reference value, said current magnitude being a direct measure of oxygen concentration, wherein the electrodes are encased in an oxygen conductive gel, comprising pHema. - View Dependent Claims (25, 26, 27)
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28. A sensor for use in a cardiac stimulation lead to measure oxygen concentration in a patient'"'"'s blood comprising:
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a substrate having opposite facing first and second sides, a plurality of electrodes mounted on the first side of the substrate, the electrodes immersed in an oxygen and electrically conductive gel, the gel being encased in a fluid impervious and oxygen transmissible sheath; an IC chip mounted on the second side of the substrate, the IC chip being encased within a sealing cap hermetically sealed to the second side of the substrate; a plurality of pads located on the substrate outside of the sealing cap and wherein a plurality of hermetic vias selectively coupled to the IC chip and pads provides electrical communication therebetween; and a plurality of electrical conductors passing through the substrate and interconnecting the electrodes to the IC chip, wherein said sensor is sized to fit within a cardiac stimulation lead. - View Dependent Claims (29, 30, 31, 32, 33)
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34. An implantable cardiac stimulation system comprising:
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a cardiac stimulation lead adapted to be in contact with a patient'"'"'s blood stream and selected cardiac sites, said stimulation lead having at least one electrical conductor; and a stimulation device comprising; a processor; and
a cardiac stimulation pulse generator coupled and responsive to the processor and configured to deliver cardiac stimulation pulses via the cardiac stimulation lead to the selected cardiac sites, said cardiac stimulation lead further comprising an oxygen monitoring circuit electrically coupled to said at least one electrical conductor and in contact with the patient'"'"'s blood stream, said oxygen monitoring circuit configured to monitor the oxygen concentration of the patient'"'"'s blood and transmit a digital signal related to said oxygen concentration to the stimulation device, wherein the stimulation device further comprises an oxygen monitoring pulse generator coupled to the processor and configured to generate a biphasic pulse train for application to the at least one electrical conductor between consecutive cardiac stimulation pulses, the pulse train defining a data frame having a pre-determined number of bits including parameter information bits, said oxygen monitoring circuit configured to detect the existence of the biphasic pulse train, wherein upon the detection of the biphasic pulse train, the oxygen monitoring circuit interrogates the patient'"'"'s blood during an interval between consecutive cardiac stimulation pulses to measure the blood oxygen concentration utilizing respective ones of the pulse train bits for carrying commands and parameter information between the processor and oxygen monitoring circuit.
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Specification