Access devices for measuring temperature of a patient

Abstract

An access device such as a catheter, or introducer, or any combination of the above is provided. Within the access device is at least one lumen, channel or instrument that carries or itself is a thermally active mass, such as infusion fluids, control wires, etc. A temperature sensor such as a thermistor is secured to the access device in order to measure the temperature of a temperature medium, typically blood, in a patient. Various insulating lumens, insulating members and mounting and extrusion configurations are provided by the invention to insulate the temperature sensor thermally from the thermal mass, which might otherwise degrade the accuracy of the temperature measurement. The invention also provides an arrangement whereby the temperature sensor is connected to an external monitor for display of the patient's temperature.

What is claimed is:  
     
         1 . A vascular access device for measuring temperature of a temperature medium of a patient, comprising: 
 an elongated access device body sized to fit within a body vessel and including a proximal and a distal end, an outer wall, and at least one lumen within the outer wall comprising a thermal mass that can flow past a predetermined location on the device body between the proximal and distal ends;    a temperature sensor supported by the device body at the predetermined location and adjacent the outer wall thereof; and    an insulating gap formed in the access device adjacent to and inward from the temperature sensor and shaped to surround the temperature sensor on an inner side thereof so as to isolate the temperature sensor from the remainder of the device body including the lumen containing the thermal mass.    
     
     
         2 . The device as in  claim 1 , wherein the device body includes an opening in the outer wall at the predetermined location, and the temperature sensor is located in the opening such that the outer wall is not interposed between the temperature sensor and the fluid within the body vessel.  
     
     
         3 . The device as in  claim 2 , further including potting compound securing the temperature sensor within the opening in the outer wall.  
     
     
         4 . The device as in  claim 3 , wherein the potting compound is dissolvable permitting the temperature sensor to directly contact the fluid within the body vessel.  
     
     
         5 . The device as in  claim 1 , wherein the device body includes an opening in the outer wall at the predetermined location, and the temperature sensor is located externally to the outer wall of the device body adjacent the opening, the temperature sensor having a signal wire attached thereto that extends through the opening and through the device body to its proximal end.  
     
     
         6 . The device as in  claim 1 , wherein the temperature sensor is mounted in a carrier that extends along the device body within the outer wall thereof from the proximal end at least to the predetermined location, and wherein the insulating gap is formed in the carrier.  
     
     
         7 . The device as in  claim 1 , wherein the insulating gap comprises a generally elongated slit extending along a portion of the length of the device body.  
     
     
         8 . The device as in  claim 1 , wherein the insulating gap is expandable.  
     
     
         9 . The device as in  claim 1 , wherein the device body is extruded and the insulating gap is formed during the extrusion process as an insulating lumen in the device body.  
     
     
         10 . The device as in  claim 9 , wherein the insulating lumen is filled with a gas.  
     
     
         11 . The device as in  claim 9 , wherein the insulating lumen is filled with a substance selected from the group consisting of: 
 ceramic pellets;    a gel; and    a piece of insulating material.    
     
     
         12 . The device as in  claim 9 , wherein the insulating lumen extends along the device body at least from the proximal end to the predetermined location, and a plug is placed therein proximal to the predetermined location.  
     
     
         13 . The device as in  claim 1 , wherein a plurality of insulating gaps are provided between the temperature sensor and the lumen containing the thermal mass.  
     
     
         14 . A vascular access device for measuring temperature of a temperature medium of a patient, comprising: 
 an elongated access device body sized to fit within a body vessel and including a proximal and a distal end, an outer wall, and at least one lumen within the outer wall comprising a thermal mass past a predetermined location on the device body between the proximal and distal ends, and an opening in the outerwall at the predetermined location;    a flexible elongated member provided in the device body that extends across the opening in the outer wall; and    a temperature sensor mounted within the flexible elongated member; and    wherein the flexible elongated member is movable within the device body such that the portion in which the temperature sensor is mounted may be displaced out of the opening thus creating an insulating gap between the temperature sensor and the lumen containing the thermal mass.    
     
     
         15 . The device as in  claim 14 , wherein a mid-portion of the flexible elongated member in which the temperature sensor is mounted is adapted to loop out of the opening.  
     
     
         16 . The device as in  claim 14 , wherein the temperature sensor is mounted in the tip of the flexible elongated member which is biased to curved outward through the opening.  
     
     
         17 . A device for measuring temperature of a temperature medium of a patient, comprising: 
 an extruded, elongated access device body sized to fit within a body vessel and including a proximal and a distal end, an outer wall, and a thermal mass at a predetermined location on the device body between the proximal and distal ends;    a temperature sensor located at the predetermined location on the device body; and    an insulating structure of a different material than the device body and co-extruded with the device body that extends between the temperature sensor and the thermal mass.    
     
     
         18 . The device as in  claim 17 , wherein the insulating structure surrounds the temperature sensor.  
     
     
         19 . The device as in  claim 18 , wherein the insulating structure defines a tube that surrounds the temperature sensor along at least a portion of the device body.  
     
     
         20 . The device as in  claim 17 , wherein the thermal mass comprises a fluid within a lumen defined in the device body, and wherein the insulating structure surrounds the lumen.