Medical sensor for reducing artifacts and technique for using the same

Abstract

A sensor may be adapted to reduce signal artifacts by deflecting the effects of outside forces and sensor motion. A sensor is provided with a rigid annular structure adapted to reduce the effect of motion of a sensor emitter and/or detector. Further, a method of deflecting or minimizing outside forces and sensor motion is also provided.

What is claimed is: 
     
         1 . A sensor comprising:
 a conformable bandage-type sensor body configured to be directly applied to a patient's digit;   an emitter and a detector disposed on a tissue contacting surface of the sensor body, wherein the emitter is configured to emit light into the patient's tissue, and wherein the detector is configured to receive the light to determine a physiological characteristic of the patient; and   a rigid structure not fixedly attached to the sensor body and comprising protrusions configured to deflect movement of the patient's digit away from the emitter and the detector, wherein the protrusions are orthogonal to the patient's digit when the rigid structure is coupled to the sensor body and wherein the rigid structure covers the sensor body in an area corresponding to the emitter and the detector and covers less than 50% of a surface area of the sensor body when the sensor is applied to the patient.   
     
     
         2 . The sensor of  claim 1 , wherein at least a portion of the rigid structure applies a pressure on the emitter, the detector, or a combination thereof. 
     
     
         3 . The sensor of  claim 1 , wherein the rigid structure comprises an arch. 
     
     
         4 . The sensor of  claim 3 , wherein the protrusions extend outwardly from terminating ends of the arch. 
     
     
         5 . The sensor of  claim 1 , wherein the protrusions comprise a damping component. 
     
     
         6 . The sensor of  claim 5 , wherein the dampening component comprises a spring. 
     
     
         7 . The sensor of  claim 1 , wherein the sensor comprises at least one of a pulse oximetry sensor or a sensor for measuring a water fraction. 
     
     
         8 . The sensor of  claim 1 , wherein the rigid structure applies pressure that secures the sensor body onto the patient's digit. 
     
     
         9 . The sensor of  claim 1 , wherein the protrusions are coupled to the rigid structure at a location corresponding to a side of the patient's digit when the rigid structure is applied to the sensor. 
     
     
         10 . A method comprising:
 applying a conformable bandage-type sensor body to a patient's finger, the conformable sensor body comprising an emitter and a detector disposed on a tissue-contacting surface of the sensor body, wherein the emitter is configured to emit light into the patient's finger; and   applying a rigid annular structure over the sensor body such that the rigid annular structure contacts the sensor body only at locations corresponding to sides of the patient's finger and wherein the rigid annular structure has a largest gap with the sensor body in an area corresponding to the emitter and the detector.   
     
     
         11 . The method of  claim 10 , wherein the sensor comprises at least one of a pulse oximetry sensor or a sensor for measuring a water fraction. 
     
     
         12 . The method of  claim 10 , wherein the rigid annular structure secures the sensor body on the patient's finger. 
     
     
         13 . The method of  claim 10 , wherein at least one of the emitter or the detector is positioned on a top of the patient's finger when the sensor body is applied. 
     
     
         14 . The method  claim 10 , wherein the rigid annular structure comprises a substantially oval shape. 
     
     
         15 . The method of  claim 10 , wherein the tissue-contacting surface of the sensor body comprises an adhesive layer. 
     
     
         16 . A physiological monitoring system comprising:
 a sensor comprising:
 a conformable bandage-type sensor body configured to be directly applied to a patient's digit; 
 an emitter and a detector disposed on a tissue contacting surface of the sensor body, wherein the emitter is configured to emit light into the patient's tissue, and wherein the detector is configured to receive a signal in response to the emitted light, wherein the signal is representative of a physiological parameter; and 
 a removable rigid structure disposed over the sensor body comprising protrusions configured to deflect movement of the patient's digit away from the emitter and the detector, wherein the protrusions extend away from the patient's tissue when the rigid structure is coupled to the sensor body and wherein the rigid structure covers the sensor body in an area corresponding to the emitter and the detector and covers less than 50% of a surface area of the sensor body when the sensor is applied to the patient; and 
   a monitor coupled to the sensor and configured to receive the signal from the detector to determine the physiological parameter.   
     
     
         17 . The physiological monitoring system of  claim 16 , wherein the removable rigid structure is an arch. 
     
     
         18 . The physiological monitoring system of  claim 17 , wherein the protrusions extend outwardly from terminating ends of the arch. 
     
     
         19 . The physiological monitoring system of  claim 16 , wherein the removable rigid structure applies a pressure to the sensor body to retain the sensor body in place on the patient's digit. 
     
     
         20 . The physiological monitoring system of  claim 19 , wherein the sensor comprises a pulse oximetry sensor or a sensor for measuring water fraction.