Fetal pulse oximetry sensor
First Claim
1. A sensor comprising:
- a base;
a probe having a first portion proximate said base and a second portion distal said base, said probe second portion embeddable within a tissue site;
a light emitting region of said probe second portion;
a light collecting region comprising a detector located proximate said base and spaced from said light emitting region;
a generally planar substrate encapsulated within said base, said substrate having a first side and a second side, said detector mounted to said substrate first side; and
an emitter mounted on said substrate proximate said probe first portion so that light is transmitted from said emitter and reflected within said probe to said light emitting region, wherein said emitter is mounted on said substrate second side and said probe first portion extends through said substrate from said first side to said emitter on said second side whereby light transmitted from said emitting region is received at said light collecting region after passing through said tissue site.
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Accused Products
Abstract
A sensor provides pulse oximetry measurements from the presenting portion of a fetus. In particular, a spiral probe is designed to attach the sensor to the fetal scalp. In one sensor configuration, a light emitting region of the probe embedded in the scalp in conjunction with a light detector located at the scalp surface measures absorption from a larger volume of the scalp tissue than conventional fetal sensors. In another sensor configuration, light emitting and light collecting regions of the probe embedded in the scalp are angled with respect to the scalp surface to measure absorption from a larger volume and deeper layers of the scalp tissue than conventional fetal sensors. These sensors increase the likelihood of measuring blood volume changes occurring in larger arterioles versus smaller arterioles or capillaries, yielding a representative measurement of central arterial oxygen saturation. These sensors also reduce the calibration errors caused by a low blood fraction. Localized arteriolar flow is stimulated with heat or vasodilating substances to reduce the effects of localized oxygen consumption and to increase blood fraction. A three-wavelength sensor is utilized to detect a low blood fraction condition.
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Citations
23 Claims
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1. A sensor comprising:
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a base;
a probe having a first portion proximate said base and a second portion distal said base, said probe second portion embeddable within a tissue site;
a light emitting region of said probe second portion;
a light collecting region comprising a detector located proximate said base and spaced from said light emitting region;
a generally planar substrate encapsulated within said base, said substrate having a first side and a second side, said detector mounted to said substrate first side; and
an emitter mounted on said substrate proximate said probe first portion so that light is transmitted from said emitter and reflected within said probe to said light emitting region, wherein said emitter is mounted on said substrate second side and said probe first portion extends through said substrate from said first side to said emitter on said second side whereby light transmitted from said emitting region is received at said light collecting region after passing through said tissue site. - View Dependent Claims (2, 3, 4, 5)
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6. A sensor comprising:
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a base;
a probe having a first portion proximate said base and a second portion distal said base;
a light emitting region of said probe second portion;
a light collecting region spaced from said light emitting region, said light collecting region comprising a detector located proximate said base, said probe second portion embeddable within a tissue site so that light transmitted from said emitting region is received at said light collecting region after passing through said tissue site;
a generally planar substrate encapsulated within said base, said substrate having a first side and a second side, said detector mounted to said substrate first side;
an emitter mounted on said substrate first side so that light is transmitted from said emitter and reflected within said probe to said light emitting region; and
a light shield separating said emitter and said detector.
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7. A sensor comprising:
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a base;
a probe having a first portion proximate said base and a second portion distal said base embeddable within a tissue site;
a light emitting region of said probe second portion; and
a light collecting region disposed in said second probe portion and spaced from said light emitting region, so that said light emitting region and said light collecting region are in a plane substantially parallel to the surface of said tissue site and are angled relative to said plane;
a generally planar substrate encapsulated within said base, said substrate having a first side and a second side, said detector and said emitter mounted to said substrate proximate said probe first portion and said emitter and said detector are mounted on the same side of said substrate; and
a light shield separating said emitter and said detector, whereby light transmitted from said emitting region is received at said light collecting region after passing through said tissue site. - View Dependent Claims (8)
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9. A sensor comprising:
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a base;
a probe having a first portion proximate said base and a second portion distal said base embeddable within a tissue site;
a light emitting region of said probe second portion; and
a light collecting region disposed in said second probe portion and spaced from said light emitting region, so that said light emitting region and said light collecting region are in a plane substantially parallel to the surface of said tissue site and are angled relative to said plane;
a generally planar substrate encapsulated within said base, said substrate having a first side and a second side, said detector and said emitter mounted to said substrate proximate said probe first portion, wherein said detector and said emitter are mounted to said substrate second side, said probe first portion extending through said substrate from said first side to said second side so that light transmitted from said emitter is reflected within said probe to said light emitting region and light received at said light collecting region is reflected within said probe to said detector; and
a light shield separating said emitter and said detector, whereby light transmitted from said emitting region is received at said light collecting region after passing through said tissue site. - View Dependent Claims (10, 11)
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12. A pulse oximetry sensor method comprising the steps of:
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embedding an emitting region of an embeddable member within a tissue site positioning a detector proximate to said tissue site so as to receive light passing through said tissue site from said emitting region, where a light collecting region of said detector is of substantially greater area than said emitting region; and
transmitting light from an emitter located proximate said tissue site and said detector through said embeddable member to said emitting region so that light from said emitting region illuminates said site. - View Dependent Claims (13)
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14. A pulse oximetry sensor method comprising the steps of:
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embedding an emitting region within a tissue site so that light from said emitting region illuminates said site;
embedding a collecting region within said tissue site distal said emitting region so as to receive light passing through said tissue site from said emitting region, said emitting region and said collecting region angled away from a surface of said tissue site;
transmitting light from an emitter located proximate said tissue site to said emitting region;
transmitting light to a detector located proximate said tissue site from said collecting region; and
absorbing light from said emitting region that is reflected from said surface so that substantially no such reflected light is received at said collecting region. - View Dependent Claims (15, 16, 17)
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18. A pulse oximetry sensor method comprising the steps of:
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measuring a first intensity ratio from a first pair of wavelengths illuminating a tissue site;
measuring a second intensity ratio from a second pair of wavelengths illuminating said tissue site;
applying a first calibration curve to said first intensity ratio to yield a first saturation value;
applying a second calibration curve to said second intensity ratio to yield a second saturation value; and
detecting a low blood fraction condition at said tissue site from the difference between said first saturation value and said second saturation value.
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19. A pulse oximetry sensor comprising:
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an emitting means for illuminating a tissue site;
a collecting means for receiving light from said emitting means after passing through said tissue site so as to measure characteristics of said tissue site, said collecting means comprising a detecting means attachable proximate said tissue site;
a probe means for embedding at least a portion of said emitting means within said tissue site and for attaching said collecting means distal said emitting means, said emitting means comprising a light generating means attachable proximate said tissue site and a transmitting means for conveying light from said generating means to a light emitting region of said probe means; and
a shielding means for blocking direct light between said light generating means and said detecting means. - View Dependent Claims (20, 21, 22, 23)
a transmitting means for conveying light from a light generating means attachable proximate said tissue site to a light emitting region of said probe means; and
a receiving means for conveying light from a light collecting region of said probe means to a light detecting means attachable proximate said tissue site.
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22. The pulse oximetry sensor of claim 21 further comprising an absorbing means for preventing light from reaching said light collecting region after reflection from the surface of said tissue site.
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23. The pulse oximetry sensor of claim 21 further comprising a shielding means for blocking direct light between said light generating means and said light detecting means.
Specification