Physiological sensor

Abstract

A sensor used to measure physiological characteristics of body tissues is provided. The physiological sensor includes a first light source assembly having a first light source in parallel with a second light source. Each of the first light source and the second light source have an anode and a cathode. A second light source assembly includes a third light source in parallel with a fourth light source. Each of the third light source and the fourth light source have an anode and a cathode. The anode of the first light source is electrically connected to the cathode of the second light source, the anode of said third light source, and the cathode of said fourth light source. The anode of the third light source is electrically connected to the cathode of the fourth light source.

1 . A system, comprising:
 a first light source assembly disposed on a sensor pad at a first location, wherein the first light source assembly comprises a first plurality of light sources configured to emit light into a body tissue;   a first detector spaced a first distance apart from the first light source assembly on the sensor pad, wherein the first detector is configured to detect the emitted light;   a second detector spaced a second distance apart from the first light source assembly on the sensor pad along an imaginary axis connecting the first light source assembly and the first detector, wherein the second detector is configured to detect the emitted light, and wherein the first light source assembly, the first detector, and the second detector are configured for cerebral or tissue oximetry; and   a second light source assembly disposed on the sensor pad at a second location, wherein the second location is offset from the imaginary axis and closer to the first and second detectors than the first location, wherein the second light source assembly comprises a second plurality of light sources configured to emit light into the body tissue, and wherein the second light source assembly and one or both of the second detectors are configured for pulse oximetry.   
     
     
         2 . The system of  claim 1 , wherein the first light source assembly is configured to emit one or more wavelengths of light suitable for cerebral or tissue oximetry deeper into the body tissue than the second light source assembly. 
     
     
         3 . The system of  claim 1 , wherein the imaginary axis intersects a sensor cable coupled to the sensor pad. 
     
     
         4 . The system of  claim 1 , wherein the second location of the second light source assembly is above the imaginary axis and closer to a first edge of the sensor pad than the first light source assembly. 
     
     
         5 . The system of  claim 1 , wherein a distance between the first and second detectors is less than the first distance. 
     
     
         6 . The system of  claim 3 , wherein the sensor cable couples the first and second light source assemblies and the first and second detectors to a monitoring device. 
     
     
         7 . The system of  claim 6 , wherein the monitoring device comprises a plurality of current sources, and wherein at least one current source of the plurality of current sources is electrically coupled to at least one light source of the first and second plurality of light sources. 
     
     
         8 . The system of  claim 6 , wherein the monitoring device is configured to activate one or more light sources of the first and second plurality of light sources. 
     
     
         9 . The system of  claim 1 , wherein at least one of the first light source assembly and the second light source assembly comprises a light emitting diode and a laser diode. 
     
     
         10 . A sensor, comprising:
 at least one sensor pad;   a first light source assembly disposed on the sensor pad at a first location, wherein the first light source assembly comprises a first plurality of light sources configured to emit light into a body tissue;   a first detector spaced a first distance apart from the first light source assembly on the sensor pad, wherein the first detector is configured to detect the emitted light;   a second detector spaced a second distance from the first light source assembly on the sensor pad, wherein the second distance is greater than the first distance, and wherein the second detector is configured to detect the emitted light; and   a second light source assembly disposed on the sensor pad at a second location, wherein the second location is farther from the first and second detectors than the first location, and wherein the second location is offset from an imaginary axis intersecting the first location, the first detector, and the second detector, and wherein the second light source assembly comprises a second plurality of light sources configured to emit light into the body tissue.   
     
     
         11 . The sensor of  claim 10 , wherein the first light source assembly, the first detector, and the second detector are configured for cerebral or tissue oximetry. 
     
     
         12 . The sensor of  claim 10 , wherein the second light source assembly and one or both of the first detector and the second detector are configured for pulse oximetry. 
     
     
         13 . The sensor of  claim 10 , wherein the first light source assembly emits one or more wavelengths of light deeper into the tissue body than the second light source assembly. 
     
     
         14 . The sensor of  claim 10 , wherein the imaginary axis is parallel to a largest edge of the sensor pad. 
     
     
         15 . The sensor of  claim 10 , wherein at least one of the first light source assembly and the second light source assembly comprise a light emitting diode and a laser diode. 
     
     
         16 . The sensor of  claim 10 , wherein the sensor pad is configured to be applied to a forehead of a patient. 
     
     
         17 . A method, comprising:
 driving one or more light sources of a first light source assembly disposed on a sensor pad at a first location, wherein the one or more light sources of the first light source assembly are configured to emit light into a body tissue;   receiving one or more first signals from one of a first detector or a second detector disposed on the sensor pad, wherein the one or more first signals are related to an amount of light detected by the first or second detector from the first light source assembly, and wherein the one or more first signals are associated with pulse oximetry monitoring;   driving one or more light sources of a second light source assembly disposed on a sensor pad at a second location, wherein the second location is farther from the first and second detectors than the first light source assembly, and wherein the one or more light sources of the second light source assembly are configured to emit light into a body tissue;   receiving one or more second signals from the first detector and the second detector, wherein the one or more second signals are related to an amount of light detected from the second light source assembly, and wherein the one or more second signals are associated with cerebral or tissue oximetry monitoring.   
     
     
         18 . The method of  claim 17 , comprising determining an arterial blood saturation of the body tissue based at least in part on the one or more first signals. 
     
     
         19 . The method of  claim 17 , comprising determining a cerebral blood saturation of the body tissue based at least in part on the one or more second signals. 
     
     
         20 . The method of  claim 17 , comprising driving the one or more light sources of the first and second light source assemblies sequentially.