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 measuring an analyte, the system comprising:
 a vascular access device configured to be in communication with a circulatory system of a host;   an analyte sensor configured to reside within the vascular access device, wherein the analyte sensor is configured to measure a concentration of an analyte within the circulatory system; and   a flow control device configured to draw blood into the vascular access device at a first flow rate of from about 0.001 ml/min to about 0.2 ml/min, wherein the flow control device is further configured to pass an infusion solution through the vascular access device at a second flow rate, wherein the first flow rate is not equal to the second flow rate.   
     
     
         2 . The system of  claim 1 , wherein the analyte is glucose. 
     
     
         3 . The system of  claim 1 , wherein the vascular access device comprises a catheter, and wherein the sensor is located within the catheter. 
     
     
         4 . The system of  claim 3 , wherein the catheter is 21 gauge or smaller. 
     
     
         5 . The system of  claim 1 , wherein the vascular access device comprises a catheter and a fluid coupler connectable to the catheter. 
     
     
         6 . The system of  claim 1 , wherein the vascular access device comprises at least one of a venous catheter or an arterial catheter. 
     
     
         7 . The system of  claim 1 , wherein the vascular access device comprises a Swann Gantz catheter. 
     
     
         8 . The system of  claim 1 , wherein the vascular access device comprises a multi-lumen catheter, and wherein the sensor is located in one of the catheter's lumens. 
     
     
         9 . The system of  claim 1 , wherein the first flow rate is configured to substantially block mixing of the infusion solution and the sample. 
     
     
         10 . The system of  claim 1 , wherein the second flow rate is from about 0.001 ml/min to about 2 ml/min. 
     
     
         11 . The system of  claim 10 , wherein the second flow rate is from about 0.02 ml/min to about 0.35 ml/min. 
     
     
         12 . The system of  claim 10 , wherein the second flow rate is configured to allow a temperature of the infusion solution to substantially equilibrate with a temperature of the host. 
     
     
         13 . A system for measuring an analyte, the system comprising:
 a vascular access device configured to be in communication with a circulatory system of a host;   an analyte sensor configured to reside within the vascular access device, wherein the analyte sensor is configured to measure a concentration of an analyte within the circulatory system; and   a valve comprising a first position and a second position that is different from the first position, wherein the system is configured such that about 150 microliters or less of a fluid passes through the vascular access device during movement of the valve at a predetermined rate between the first position and the second position during a predetermined amount of time.   
     
     
         14 . The system of  claim 12 , wherein the system is configured to push fluid through the vascular access device during movement of the valve from the first position to the second position. 
     
     
         15 . The system of  claim 12 , wherein the valve is configured such that about 50 microliters or less of a fluid passes through the vascular access device during the movement of the valve between the first position and the second position.