Catheters permitting controlled diffusion

Claim 2

A catheter including a reservoir having in use at least one bio-compatible non-thrombogenic surface; said reservoir being defined by flexible spaced apart walls at least one of which is a bio-compatible polymeric material through which anticoagulant solution contained in use by said reservoir may permeate thus providing a predetermined and controlled diffusion rate of anticoagulant solution, wherein said reservoir is formed from a collapsible flexible tube of said bio-compatible polymeric material having a hollow wall consisting of an inner wall defining a central lumen and an outer wall separable from the inner wall so as to define a substantially annular interwall passageway, the inner and outer walls fully enclosing the interwall passageway along an entire length of the catheter to form said reservoir.

Claim 3

A catheter as claimed in claim 1, wherein injection means are operatively associated with said hollow wall tube and whereby anticoagulant solution may be injected into and maintained under pressure in said interwall passageway.

Claim 4

A catheter as claimed in claim 1, wherein the inner and outer walls of the hollow wall tube merge at one end of said tube and are sealed at their free ends to at least one sealing member thereby enclosing said interwall passageway.

Claim 5

A catheter as claimed in claim 2, wherein the inner and outer walls of the hollow wall tube merge at one end of said tube and are sealed at their free ends to at least one sealing member thereby enclosing said interwall passageway.

Claim 6

A catheter as claimed in claim 1, wherein said bio-compatible polymeric material is formed as a continuous surface of said reservoir.

Claim 7

A cardiac assist device comprising: a reservoir having in use at least one continuous bio-compatible non-thrombogenic surface; said reservoir being defined by flexible spaced apart walls at least one of which is a bio-compatible polymeric material through which anticoagulant solution contained in use by said reservoir may permeate thus providing a predetermined and controlled diffusion rate of anticoagulant solution and wherein said reservoir is defined between an inner wall of a continuous surface of flexible gas tight material forming a bladder and an outer wall of said bio-compatible polymeric material spaced apart from said inner wall so as to define a substantially annular interwall passageway, the inner and outer walls fully enclosing the interwall passageway along an entire length of the cardiac assist device; said inner and outer walls merging with an integral hollow walled entry tube to the interior of the bladder; means for introducing anticoagulant solution into said reservoir; and means for controlled inflation and deflation of said bladder which is continually inflated and deflated in use.

Claim 8

A cardiac assist device comprising: a reservoir having in use at least one continuous bio-compatible non-thrombogenic surface; said reservoir being defined by flexible spaced apart walls at least one of which is a bio-compatible polymeric material through which anticoagulant solution contained in use by said reservoir may permeate thus providing a predetermined and controlled diffusion rate of anticoagulant solution and wherein said reservoir is defined between an inner wall of a continuous surface of flexible gas tight material forming a bladder and an outer wall of said bio-compatible polymeric material spaced apart from said inner wall so as to define a substantially annular interwall passageway, the inner and outer walls fully enclosing the interwall passageway along an entire length of the cardiac assist device; said inner and outer walls merging with an integral hollow walled entry tube to the interior of the bladder; means for introducing anticoagulant solution into said reservoir; and means for controlled inflation and deflation of said bladder which is continually inflated and deflated in use.

Claim 9

A cardiac assist device as claimed in claim 6, wherein a collar of permeable material defines, with the outer wall of the assist device entry tube, an annular chamber into which antibacterial solution can be injected, said annular chamber being located in use where the entry tube passes through skin and tissue.