Adjustable connector and dead space reduction

Abstract

Methods and systems for determining the concentration of one or more analytes from a sample such as blood or plasma are described. The systems described herein can be configured to withdraw a certain volume of sample from a source of bodily fluid, direct a first portion of the withdrawn sample to an analyte monitoring system and return a second portion of the sample to the patient. The analyte monitoring system can be connected to the source of bodily fluid via a connector that is configured to maintain uniform velocity across the connector and reduce the dead space volume.

1 .- 7 . (canceled) 
     
     
         8 . A penetrating connector configured to be positioned along a fluid line between a medical device and a source of body fluid to allow fluid flow while reducing leaks and non-laminar flow, the connector comprising
 first and second openings at either end of the connector, the openings configured to:
 allow fluid communication—through the connector—between the medical device and the source of body fluid; and 
 cooperate with openings of other connecting fittings or tubes that comprise the fluid line to assist in forming mating complexes at either side end of the connector, at least one of the mating complexes having an enlarged space; 
   an extender tube having a first cross-sectional width, the extender tube configured to:
 convey the fluid along a fluid pathway that extends at least part of the way between the first and second openings; and 
 penetrate through at least one of the mating complexes while bypassing the enlarged space, which has a cross sectional width that is wider than the first cross-sectional width; 
 confine fluid within its walls to prevent the fluid from flowing out into the enlarged space of the mating complex; and 
 abut an opening of a connecting fitting such that fluid flows directly between the extender tube and the opening of the connecting fitting; and 
   a force-exerting structure that uses a resilient property to improve a seal, the seal located where the extender tube abuts the opening of the connecting fitting.   
     
     
         9 . The penetrating connector of  claim 8 , wherein the extender tube comprises a resilient portion, and the resilient portion is the force-exerting structure. 
     
     
         10 . (canceled) 
     
     
         11 . (canceled) 
     
     
         12 . The penetrating connector of  claim 8 , wherein the force-exerting structure comprises a spring. 
     
     
         13 . The penetrating connector of  claim 8 , wherein the force-exerting structure comprises a supporting structure at least partially surrounding the extender tube. 
     
     
         14 . The penetrating connector of  claim 8 , wherein the extender tube comprises polyimide. 
     
     
         15 . The penetrating connector of  claim 8 , wherein the force-exerting structure has a stiffness greater than stiffness of an inner portion of the mating complex surrounding the enlarged space. 
     
     
         16 . The penetrating connector of  claim 8 , wherein the force-exerting structure comprises a stiff tip of the extender tube. 
     
     
         17 . The penetrating connector of  claim 8 , further comprising a hub positioned along the fluid line between the medical device and the source of bodily fluid. 
     
     
         18 . The penetrating connector of  claim 17 , wherein the hub is disposed between the extender tube and a tube connected to the medical device. 
     
     
         19 . The penetrating connector of  claim 18 , further comprising a spring enclosed within the connector, wherein the hub is permanently adhered to both the extender tube and the tube connected to the medical device, and wherein the hub further provides a pushing surface for the spring, such that when the connector is mated with the connecting fitting, the spring pushes the hub, which in turn pushes the extender tube, urging it more snuggly into the opening of the connecting fitting to improve the seal where the extender tube abuts the opening of the connecting fitting. 
     
     
         20 . The penetrating connector of  claim 8 , wherein the connecting fitting comprises a standard Luer connector. 
     
     
         21 . The penetrating connector of  claim 8 , wherein the connecting fitting is connected to a central venous catheter. 
     
     
         22 . The penetrating connector of  claim 8 , wherein the connecting fitting is connected to a peripheral venous catheter. 
     
     
         23 . The penetrating connector of  claim 8 , wherein the connecting fitting is selected from a group consisting of connectors with standard Luer threading and having a linear depth between an entrance to the standard medical connector and the inner lumen in the range of approximately 6.9 mm to approximately 19.8 mm, and wherein the force-exerting structure is configured to cause the extender tube to resiliently protrude through a similar range such that the penetrating connector can accommodate standard medical connectors having depths in the range of approximately 6.9 mm to approximately 19.8 mm while protruding fully into the interior volume of each and resiliently abutting the lumen of each such standard medical connector