Implantable blood oxygen sensor and method of use
First Claim
1. A body-implantable sensor and lead comprising:
- an implantable stimulating lead having a connector at one end thereof and electrode means at the other end thereof, the electrode means comprising means for electrically contacting body tissue when the lead is implanted in a body, and the connector comprising a means for interfacing the lead, both electrically and physically, with a desired stimulating device;
a first insulated conductor having a distal end coupled to the electrode means and a proximal end couplled to the connector;
sensor means forming an integral part of the lead for quantitatively sensing a specified characteristic of a body fluid proximal the sensor means, the sensor means including means responsive to a drive signal for generating an output signal that varies as a function of the specified body fluid characteristic;
means for transmitting the drive signal and the output signal between the sensor means and the connector; and
means for hermetically sealing said sensor means.
2 Assignments
0 Petitions
Accused Products
Abstract
An implantable medical sensor (42) determines the oxygen content of blood. The sensor includes a miniaturized hybrid circuit (130) that includes light-emitting diode means (32), phototransistor means (34, 36), and a substrate (110) to which the light-emitting diode means and phototransistor means are bonded in a desired circuit configuration. The hybrid circuit is hermetically sealed within a cylindrical body (140) made from a material that is substantially transparent to light, such as glass. Feedthrough terminals (132, 134) provide means for making an electrical connection with the hybrid circuit. The light-emitting diode means is driven with a stair-stepped current pulse. In one embodiment, the sensor is embedded within a bilumen pacemaker lead (60) and positioned near the distal electrode (66) of the lead so that the sensor resides within the heart when the lead is implanted within a patient, thereby allowing the sensed oxygen content (MVO2 concentration) of the blood within the heart to be a physiological parameter that can be used to control the pacing interval of a rate-responsive pacemaker (56).
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Citations
34 Claims
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1. A body-implantable sensor and lead comprising:
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an implantable stimulating lead having a connector at one end thereof and electrode means at the other end thereof, the electrode means comprising means for electrically contacting body tissue when the lead is implanted in a body, and the connector comprising a means for interfacing the lead, both electrically and physically, with a desired stimulating device; a first insulated conductor having a distal end coupled to the electrode means and a proximal end couplled to the connector; sensor means forming an integral part of the lead for quantitatively sensing a specified characteristic of a body fluid proximal the sensor means, the sensor means including means responsive to a drive signal for generating an output signal that varies as a function of the specified body fluid characteristic; means for transmitting the drive signal and the output signal between the sensor means and the connector; and means for hermetically sealing said sensor means. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18)
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19. An implantable oxygen sensor and lead used with an implantable rate-responsive pacing system;
- said pacing system including timing means for generating timing signals and for defining a pacing interval, and pulse generator means for generating stimulating pulses at appropriate times within said pacing interval;
said timing means including control circuits for automatically adjusting the pacing interval of said pacing system as a function of the oxygen content of body blood sensed by said oxygen sensor, said implantable oxygen sensor and lead comprising;means responsive to a drive signal for emitting a measuring signal into said body blood, said measuring signal being of a type that is affected by the oxygen content of said blood; means for receiving the measuring signal after it has been emitted into said body blood and affected by the oxygen content thereof; lead means for delivering the stimulation pulses from the pulse generator to a desired body location;
an implantable hermetically sealed case within said lead means wherein said emitting means and receiving means are housed;control means for generating said drive signal; and processing means coupled to said receiving means for processing the receiving measuring signal and for generating an output signal indicative of the oxygen content of said blood. - View Dependent Claims (20, 21, 22)
- said pacing system including timing means for generating timing signals and for defining a pacing interval, and pulse generator means for generating stimulating pulses at appropriate times within said pacing interval;
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23. A hermetically sealed, implantable medical sensor used to sense a desired parameter associated with body tissue, including body fluids, in which said medical sensor is implanted, said sensor comprising:
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a hollow tube having sealed window means therein; a substrate inserted into said tube; light-emitting diode means placed on said substrate for emitting light of a prescribed frequency range in response to a drive signal, said light-emitting diode means being positioned on said substrate so as to permit at least a portion of said light to pass through said window means, contact body tissue outside of said window means, and reflect back through said window means; phototransistor means placed on said substrate for receiving light of a prescribed frequency range received through said window means, and for generating an output signal having characteristics that vary as a function of at least one parameter of the light received through said window means; connection means for connecting said light-emitting diode means and said phototransistor means is a desired circuit configuration, and for connecting a first terminal to said light-emitting diode means, and for connecting a second terminal to said phototransistor means; sealing means sealably secured to each end of said tube for sealing said substrate, light-emitting diode means, phototransistor means, and connection means within said tube, said sealing means including feedthrough means for making electrical contact from a point external said tube with said first and second terminals; means for generating said drive signal and applying it through said first and second terminals to said light-emitting diode means; and means for monitoring through said first and second terminals the output signal generated by said phototransistor means, and for processing said signal to provide a sensor signal indicative of said at least one parameter of the light received through said window means, said sensor signal thereby providing a measure of a desired characteristic of said body tissue as measured by the manner in which said at least one parameter of light is affected by coming in contact with said body tissue. - View Dependent Claims (24, 25, 26, 27, 28, 29, 30, 31)
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32. A method of using a medical sensor that includes light-emitting diode means for emitting a light pulse that is directed to a desired type of organic material to be analyzed, which light pulse is then received by phototransistor means, a desired property of said organic material being determinable in accordance with the manner in which at least one detectable property of the light pulse is affected by the organic material;
- said method comprising the steps of;
(a) exciting said light-emitting diode means with a first drive current for a first period of time; (b) exciting said light-emitting diode means with a second drive current for a second period of time immediately subsequent said first period of time; (c) monitoring the light pulses received by said phototransistor means during said first and second periods of time to determine the change in said light pulses as a result of having come in contact with the organic material; and (d) processing the amount of change identified in step (c) to determine a desired property of the organic material. - View Dependent Claims (33, 34)
- said method comprising the steps of;
Specification