Variable volume infusion port

Abstract

A variable volume infusion port is provided. The infusion port may include a port body having an internal fluid reservoir, a septum, a stem to fluidly couple to a catheter lumen, and a displaceable member disposed in the internal fluid reservoir. In a first position, the displaceable member is disposed proximate the septum, providing a relatively small fluid volume within the infusion port. Insertion of an injection device through the septum causes the displaceable member to move to a second location distal from the septum, providing a relatively large fluid volume within the infusion port for the duration the injection device remains in the infusion port. The displaceable member may include a rigid member operably coupled to a biasing element or a flexible member coupled to a biasing element.

What is claimed is: 
     
         1 . A variable volume infusion port, comprising:
 a hollow body forming a reservoir, the hollow body including a body portion and a housing;   a septum disposed between the body portion and the housing;   an opening on a surface of the housing to permit access to the septum;   a hollow stem in fluid communication with the reservoir, the hollow stem projecting at least partially from the hollow body; and   a displaceable member disposed in the reservoir to provide a variable volume reservoir;
 the displaceable member biased, in the absence of an insertion of an injection device into the reservoir, to a first position proximate the septum such that the reservoir contains a first fluid volume; 
 at least a portion of the displaceable member displaceable by the insertion of the injection device into the reservoir to a second position distal from the septum such that the reservoir contains a second fluid volume that is greater than the first fluid volume. 
   
     
     
         2 . The variable volume infusion port of  claim 1  wherein the first fluid volume comprises 15% or less of the second fluid volume. 
     
     
         3 . The variable volume infusion port of  claim 1  wherein the displaceable member comprises a rigid member. 
     
     
         4 . The variable volume infusion port of  claim 3  wherein one or more springs bias the rigid member to the first position to provide the first fluid volume and wherein the insertion of the injection device into the reservoir compresses the one or more springs and displaces the rigid member to the second position to provide the second fluid volume. 
     
     
         5 . The variable volume infusion port of  claim 4  wherein the one or more springs comprise at least one of: one or more helical springs; one or more coil springs; one or more conical springs; or one or more volute springs. 
     
     
         6 . The variable volume infusion port of  claim 3  wherein the rigid member comprises a laminated rigid member that includes a metallic member and a polymer layer disposed proximate at least a portion of the metallic member. 
     
     
         7 . The variable volume infusion port of  claim 6  wherein the laminated rigid member further comprises a silicone layer disposed proximate at least a portion of the polymer layer. 
     
     
         8 . The variable volume insertion port of  claim 3  wherein the displaceable member comprises a rigid member having an upper surface and a transversely opposed lower surface, wherein the upper surface includes one or more surface features to promote flow towards the hollow stem. 
     
     
         9 . The variable volume infusion port of  claim 1  wherein the displaceable member comprises a deformable member. 
     
     
         10 . The variable volume infusion port of  claim 9  wherein the deformable member comprises a flexible membrane disposed in the reservoir, wherein the flexible membrane affixes at least a portion of a perimeter of the deformable member to at least a portion of an interior surface forming the reservoir. 
     
     
         11 . The variable volume infusion port of  claim 9  wherein the insertion of the injection device into the reservoir causes the deformable member to deform to the second position to provide the second fluid volume. 
     
     
         12 . The variable volume infusion port of  claim 9  wherein the deformable member comprises an elastomeric solid affixed to the base of the hollow body. 
     
     
         13 . The variable volume infusion port of  claim 1  wherein the hollow body and the septum comprise a subcutaneous infusion port. 
     
     
         14 . A variable volume infusion port, comprising:
 a means for providing a reservoir in a subcutaneous infusion port;   a means for varying a fluid volume of the reservoir responsive to insertion of an injection device at least partially into the reservoir such that in the absence of the injection device, the reservoir contains a first fluid volume and in the presence of the injection device, the reservoir contains a second fluid volume that is greater than the first fluid volume.   
     
     
         15 . The variable volume infusion port of  claim 14 , further comprising:
 a coupling means for fluidly coupling the reservoir to an intravenous catheter.   
     
     
         16 . The volume infusion port of  claim 15  wherein the means for varying the fluid volume comprises an elastomeric means for varying the fluid volume. 
     
     
         17 . The volume infusion port of  claim 15  wherein the means for varying the fluid volume comprises a displaceable rigid means for varying the fluid volume. 
     
     
         18 . The variable volume infusion port of  claim 17  wherein the displaceable rigid means further comprises:
 a directional flow means carried by the displaceable rigid means, the directional flow means to direct flow from the fluid volume to the coupling means. 
 
     
     
         19 . A variable volume infusion port, comprising:
 an infusion port forming an internal reservoir having a longitudinal axis;   a displaceable member disposed at least partially within the internal reservoir, transverse to the longitudinal axis, the displaceable member to provide a variable fluid volume in the internal reservoir;   the displaceable member biased, in the absence of an insertion of an injection device into the internal reservoir, to a first position along the longitudinal axis, the first position to provide a first fluid volume within the internal reservoir;   wherein the insertion of the injection device into the fluid reservoir displaces at least a portion of the displaceable member to a second position along the longitudinal axis, the second position to provide a second fluid volume within the internal reservoir that is greater than the first volume.   
     
     
         20 . The variable volume infusion port of  claim 19  wherein the first fluid volume comprises 15% or less of the second fluid volume.