Analyte sensor

Abstract

Systems and methods of use for continuous analyte measurement of a host's vascular system are provided. In some embodiments, a continuous glucose measurement system includes a vascular access device, a sensor and sensor electronics, the system being configured for insertion into communication with a host's circulatory system.

1 . A system for monitoring analyte concentration in a biological fluid of a host, the system comprising:
 an analyte sensor configured to produce a data signal indicative of an analyte concentration in a host during exposure of the sensor to a biological fluid;   a vascular access device configured for communication with a circulatory system of a host, wherein the vascular access device comprises a catheter configured for insertion into the host's circulatory system and tubing;   a high oxygen solubility material that has at least about 3×higher oxygen solubility than aqueous media;   a infusion solution, wherein the oxygen concentration of the infusion solution is greater than the oxygen concentration of the biological fluid; and   a flow control device configured to intermittently expose the sensor to the biological fluid and to the infusion solution, wherein the flow control device is configured to draw back the biological fluid into the catheter but not substantially into the tubing during a first phase, and to infuse the infusion solution through the catheter into the host during a second phase.   
     
     
         2 . The system of  claim 1 , wherein oxygen is absorbed during the second phase and released during the first phase. 
     
     
         3 . The system of  claim 1 , wherein the sensor is located within the catheter. 
     
     
         4 . The system of  claim 1 , wherein the vascular access device further comprises a fluid coupler connectable to the catheter. 
     
     
         5 . The system of  claim 4 , wherein the sensor is located within the fluid coupler. 
     
     
         6 . The system of  claim 4 , wherein the flow control device is configured to draw back the sample volume into the fluid coupler, but substantially no farther than the fluid coupler. 
     
     
         7 . The system of  claim 4 , wherein the sensor is held by the fluid coupler. 
     
     
         8 . The system of  claim 1 , wherein the catheter is at least one of a venous catheter or an arterial catheter. 
     
     
         9 . The system of  claim 1 , wherein the catheter is a Swan-Ganz catheter. 
     
     
         10 . The system of  claim 1 , wherein the infusion solution comprises saline. 
     
     
         11 . The system of  claim 1 , wherein the sensor comprises the high oxygen solubility material. 
     
     
         12 . The system of  claim 1 , wherein the flow control device is configured to draw back a sample volume of from about 15 μL to about 2 mL of the biological fluid during a first phase. 
     
     
         13 . The system of  claim 12 , wherein the sample volume is from about 20 μl to about 1 ml. 
     
     
         14 . The system of  claim 13 , wherein the sample volume is from about 20 μl to about 500 μl. 
     
     
         15 . The system of  claim 14 , wherein the sample volume is from about 25 μl to about 150 μl. 
     
     
         16 . The system of  claim 1 , wherein the analyte comprises at least one analyte selected from the group consisting of glucose, O 2 , CO 2 , PCO 2 , PO 2 , potassium, sodium, pH, lactate, urea, bilirubin, creatinine, hematocrit, and combinations thereof. 
     
     
         17 . The system of  claim 1 , wherein the analyte is glucose. 
     
     
         18 . The system of  claim 1 , wherein second phase is longer than the first phase. 
     
     
         19 . The system of  claim 1 , wherein a volume of the infusion solution moved during the second phase is greater than a volume of the biological fluid moved during the first phase. 
     
     
         20 . The system of  claim 1 , wherein the high oxygen solubility material comprises a polymer selected from the group consisting of a hydrocarbonaceous polymer, an oxyhydrocarbon polymer, and combinations thereof. 
     
     
         21 . The system of  claim 1 , wherein the high oxygen solubility material comprises a polymer selected from the group consisting of silicone, fluorocarbon and perfluorocarbons. 
     
     
         22 . The system of  claim 1 , wherein the high oxygen solubility material has an oxygen permeability of from about 1 Barrer to about 1000 Barrers.