Fetal pulse oximetry sensor

A sensor comprising:

• 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.

A sensor comprising:

• 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.

A sensor comprising:

• 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.

A pulse oximetry sensor method comprising the steps of:

• 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.

A pulse oximetry sensor method comprising the steps of:

• 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.

A pulse oximetry sensor method comprising the steps of:

• 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.

A pulse oximetry sensor comprising:

• 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.