Medical sensor and technique for using the same

Abstract

A sensor is provided that is appropriate for transcutaneous detection of tissue or blood constituents. A sensor for tissue constituent detection may include a gas collection chamber with a conduit to a sensing component and a conduit from the sensing component to the chamber. A sensor as provided may also include a barrier layer to prevent water from infiltrating the sensor.

1 . A system comprising: 
 at least one gas collection chamber into which a tissue constituent is able to diffuse, wherein the gas collection chamber is adapted to be placed proximate to a tissue;    an efferent conduit adapted to transfer the tissue constituent from the gas collection chamber to at least one sensing component, wherein the sensing component is adapted to provide a signal related to the tissue constituent;    an afferent conduit adapted to transfer the tissue constituent from the sensing component to the gas collection chamber; and    a motive force structure adapted circulate the tissue constituent through the system, wherein the motive force structure is adapted to be operatively connected to at least one of the efferent conduit, the afferent conduit, or the sensing component.    
   
   
       2 . The system, as set forth in  claim 1 , wherein the tissue constituent comprises carbon dioxide, oxygen, ethanol, or carbon monoxide.  
   
   
       3 . The system, as set forth in  claim 1 , wherein the tissue constituent comprises a volatile anesthetic agent, a volatile product of metabolism, or a volatile xenobiotic.  
   
   
       4 . The system, as set forth in  claim 1 , comprising a calibration element adapted to provide at least one signal related to at least one physical characteristic of the gas collection chamber.  
   
   
       5 . The system, as set forth in  claim 4 , wherein the calibration element comprises a coded resistor or an electrically erasable programmable read-only memory.  
   
   
       6 . The system, as set forth in  claim 1 , comprising a barrier layer defining at least part of a surface of the gas collection structure, wherein the barrier layer is substantially impermeable to water.  
   
   
       7 . The system, as set forth in  claim 1 , comprising a barrier layer defining at least part of a surface of the gas collection structure, wherein the barrier layer is selectively permeable to the tissue constituent.  
   
   
       8 . The system, as set forth in  claim 1 , comprising a water-permeable conduit that is impermeable to the tissue constituent, wherein the water-permeable conduit is adapted to direct water away from gas collection structure.  
   
   
       9 . The system, as set forth in  claim 1 , wherein the sensing component comprises a non-optical transducer, an optical transducer, a chemical indicator, a spectroscopic transducer, or an electrochemical transducer.  
   
   
       10 . The system, as set forth in  claim 1 , wherein the gas collection structure comprises a tube, wherein at least a portion of the tube adapted to be placed proximate to the tissue is permeable to the tissue constituent.  
   
   
       11 . The system, as set forth in  claim 1 , wherein the sensing component comprises a calibration element adapted to provide a signal related to the calibration characteristics of the sensing component.  
   
   
       12 . The system, as set forth in  claim 1 , wherein the motive force structure comprises a pump, a one-way valve, a kinetic motion structure, or a piezoelectrically powered structure.  
   
   
       13 . The system, as set forth in  claim 1 , comprising an agent adapted to be placed proximate to the tissue, wherein the agent is adapted to increase blood flow to the tissue or wherein the agent is adapted to increase the tissue's permeability to the tissue constituent.  
   
   
       14 . The system, as set forth in  claim 13 , wherein the agent comprises an electrical heating element, a chemical heating element, nicotinic acid, or salicylic acid.  
   
   
       15 . A monitoring device comprising: 
 a monitor; and    a system adapted to be coupled to the monitor, the system comprising:    at least one gas collection structure adapted to be placed proximate to a tissue; and    an efferent conduit adapted to transfer gas from the gas collection structure to a sensing component, wherein the sensing component is adapted to provide a signal related to a tissue constituent; and    an afferent conduit adapted to transfer gas from the sensing component to the gas collection structure.    
   
   
       16 . The monitoring device, as set forth in  claim 15 , wherein the tissue constituent comprises carbon dioxide, oxygen, ethanol, or carbon monoxide.  
   
   
       17 . The monitoring device, as set forth in  claim 15 , wherein the tissue constituent comprises a volatile anesthetic agent, a volatile product of metabolism, or a volatile xenobiotic.  
   
   
       18 . The monitoring device, as set forth in  claim 15 , comprising a calibration element adapted to provide at least one signal related to at least one physical characteristic of the gas collection chamber.  
   
   
       19 . The monitoring device, as set forth in  claim 18 , wherein the calibration element comprises a coded resistor or an electrically erasable programmable read-only memory.  
   
   
       20 . The monitoring device, as set forth in  claim 15 , comprising a barrier layer defining at least part of a surface of the gas collection structure, wherein the barrier layer is substantially impermeable to water.  
   
   
       21 . The monitoring device, as set forth in  claim 15 , comprising a barrier layer defining at least part of a surface of the gas collection structure, wherein the barrier layer is selectively permeable to the tissue constituent.  
   
   
       22 . The monitoring device, as set forth in  claim 15 , comprising a water-permeable conduit that is impermeable to the tissue constituent, wherein the water-permeable conduit is adapted to direct water away from gas collection structure.  
   
   
       23 . The monitoring device, as set forth in  claim 15 , wherein the sensing component comprises a non-optical transducer, an optical transducer, a chemical indicator, a spectroscopic transducer, or an electrochemical transducer.  
   
   
       24 . The monitoring device, as set forth in  claim 15 , wherein the gas collection structure comprises a tube, wherein at least a portion of the tube adapted to be placed proximate to the tissue is permeable to the tissue constituent.  
   
   
       25 . The monitoring device, as set forth in  claim 15 , wherein the sensing component comprises a calibration element adapted to provide a signal related to the calibration characteristics of the sensing component.  
   
   
       26 . The monitoring device, as set forth in  claim 15 , wherein the motive force structure comprises a pump, a one-way valve, a kinetic motion structure, or a piezoelectrically powered structure.  
   
   
       27 . The monitoring device, as set forth in  claim 15 , comprising an agent adapted to be placed proximate to the tissue, wherein the agent is adapted to increase blood flow to the tissue or wherein the agent is adapted to increase the tissue's permeability to the tissue constituent.  
   
   
       28 . The monitoring device, as set forth in  claim 27 , wherein the agent comprises an electrical heating element, a chemical heating element, nicotinic acid, or salicylic acid.  
   
   
       29 . The monitoring device, as set forth in  claim 15 , comprising a multi-parameter monitor.  
   
   
       30 . A method comprising: 
 transferring a tissue constituent in a gas collection chamber to at least one sensing component not located in the gas collection chamber, wherein the sensing component is adapted to provide a signal related to the tissue constituent.    
   
   
       31 . The method, as set forth in  claim 30 , comprising contacting the tissue constituent with a barrier layer defining at least part of a surface of the gas collection structure, wherein the barrier layer is substantially impermeable to water.