Apparatus for the dialysis of blood, method for fabricating the same, and method for the dialysis of blood

Abstract

Improved apparatus for the dialysis of blood, a method for fabricating the same, and an improved method for the dialysis of blood.

What is claimed is:  
     
         1 . A catheter comprising at least one flexible tubular element, said at least one tubular element having an open proximal end, an open distal end and a side wall defining a lumen extending between said open proximal end and said open distal end, said side wall (1) being formed of a biocompatible material, (2) encasing a reinforcing means therein for reinforcing said side wall, and (3) having a smooth interior surface for defining said lumen, said smooth interior surface being sufficiently smooth that said at least one tubular element may be used for hemodialysis applications with good results.  
     
     
         2 . A catheter according to  claim 1  wherein the average variation in the local surface profile of said lumen is less than about 0.0015 inch.  
     
     
         3 . A catheter according to  claim 1  wherein said biocompatible material comprises silicone rubber.  
     
     
         4 . A catheter according to  claim 3  wherein said biocompatible material comprises silicone rubber having a hardness of approximately 80 durometer.  
     
     
         5 . A catheter according to  claim 1  wherein said reinforcing means are formed out of a material stiffer than the material used to form said side wall.  
     
     
         6 . A catheter according to  claim 5  wherein said reinforcing means are formed out of metal.  
     
     
         7 . A catheter according to  claim 6  wherein said reinforcing means are formed out of titanium.  
     
     
         8 . A catheter according to  claim 6  wherein said reinforcing means are formed out of stainless steel.  
     
     
         9 . A catheter according to  claim 5  wherein said reinforcing means are formed out of plastic.  
     
     
         10 . A catheter according to  claim 1  wherein said reinforcing means comprise a coil spring.  
     
     
         11 . A catheter according to  claim 10  wherein the wire forming said coil spring has a thickness of approximately 0.006 inch and a coil rate of approximately 0.031-0.038 pitch.  
     
     
         12 . A catheter according to  claim 10  wherein said coil spring comprises titanium.  
     
     
         13 . A catheter according to  claim 12  wherein the wire forming said coil spring has a thickness of approximately 0.006 inch and a coil rate of approximately 0.031-0.038 pitch.  
     
     
         14 . A catheter according to  claim 1  wherein said reinforcing means comprise a plurality of ring-like elements.  
     
     
         15 . A catheter according to  claim 1  wherein said reinforcing means are formed out of a radio-opaque material.  
     
     
         16 . A catheter according to  claim 1  wherein said side wall has a thickness of approximately 0.015 inch.  
     
     
         17 . A catheter according to  claim 1  wherein said at least one side wall comprises a smooth outer surface.  
     
     
         18 . A catheter according to  claim 1  further comprising a support structure attached to said side wall adjacent to said open distal end of said at least one flexible tubular element.  
     
     
         19 . A catheter according to  claim 18  wherein said support structure is at least partially embedded in said side wall.  
     
     
         20 . A catheter according to  claim 16  wherein said support structure is formed out of a radio-opaque material.  
     
     
         21 . A catheter according to  claim 18  wherein said at least one tubular element is substantially cylindrical, and further wherein said support structure comprises a ring-shaped element formed of a material more rigid than the biocompatible material forming said at least one tubular element.  
     
     
         22 . A catheter according to  claim 18  wherein said at least one tubular element is substantially cylindrical, and further wherein said support structure comprises a substantially cylindrical element having an outer diameter, a distal end, a proximal end, a first inner diameter portion adjacent to said distal end, a second inner diameter portion adjacent to said proximal end, and a proximally-facing shoulder connecting said first and second inner diameter portions.  
     
     
         23 . A catheter according to  claim 18  wherein said at least one tubular element is substantially cylindrical, and further wherein said support structure comprises a substantially cylindrical element defining at least one opening therethrough.  
     
     
         24 . A catheter according to  claim 23  wherein said at least one opening comprises a slot extending to said proximal end of said support structure.  
     
     
         25 . A catheter according to  claim 1  further comprising a support structure attached to said side wall adjacent to, but spaced from, said open distal end of said at least one flexible tubular element.  
     
     
         26 . A catheter according to  claim 1  wherein said side wall defines at least one opening therethrough in proximally-spaced, proximate relation to said open distal end of said at least one flexible tubular element.  
     
     
         27 . A catheter according to  claim 26  wherein said at least one opening comprises a substantially circular hole.  
     
     
         28 . A catheter according to  claim 26  wherein said at least one opening comprises a longitudinally-extending slit.  
     
     
         29 . A catheter according to  claim 28  wherein said slit is normally substantially closed, but is capable of opening when a positive internal pressure is established in said lumen.  
     
     
         30 . A catheter according to  claim 1  wherein said catheter comprises a pair of said flexible tubular elements longitudinally joined together in side-by-side relation to one another.  
     
     
         31 . Apparatus for use in the dialysis of the blood of a patient, said apparatus comprising a connector portion and a catheter portion; 
 said connector portion comprising an outlet adapted for communication with a line connected to the input port of a dialysis machine, and an inlet adapted for communication with a line connected to the output port of a dialysis machine; and    said catheter portion comprising a catheter element comprising:    a suction line and a return line, each said line comprising a flexible tubular element, said tubular element having an open proximal end, an open distal end and a side wall defining a lumen extending between said open proximal end and said open distal end, said side wall (1) being formed of a biocompatible material, (2) encasing reinforcing means therein for reinforcing said side wall, and (3) having a smooth interior surface for defining said lumen, said smooth interior surface being sufficiently smooth that said tubular element may be used for hemodialysis applications with good results;    said proximal end of said suction line being connected to said connector portion and in communication with said outlet, and said distal end of said suction line terminating in a suction line mouth;    said proximal end of said return line being connected to said connector portion and in communication with said inlet, and said distal end of said return line terminating in a return line mouth;    said suction line and said return line being adapted for disposition within the body of the patient so that said suction line mouth and said return line mouth are both disposed in the vascular system of the patient.    
     
     
         32 . Apparatus according to  claim 31  wherein said connector portion comprises an extracorporeal connector element adapted for attachment against an outside surface of the body of the patient.  
     
     
         33 . Apparatus according to  claim 31  wherein said connector portion comprises a subcutaneous port element adapted for implantation within the body of the patient.  
     
     
         34 . A method for making a catheter, said method comprising the steps of: 
 (a) providing an elongated, removable molding core;    (b) forming a tubular element of biocompatible material on said molding core;    (c) positioning reinforcing means for reinforcing said tubular element on the outer surface of said tubular element;    (d) forming an overlayer of biocompatible material over said tubular element and said reinforcing means; and    (e) removing said molding core from the coated tubular element.    
     
     
         35 . A method according to  claim 34  wherein said tubular element is formed on said molding core by co-extruding said tubular element about the outer surface of said molding core.  
     
     
         36 . A method according to  claim 34  wherein said step of removing said molding core from said coated tubular element comprises reducing the transverse cross-section of said molding core.  
     
     
         37 . A method according to  claim 36  wherein reducing the transverse cross-section of said elongated molding core comprises stretching said molding core longitudinally.  
     
     
         38 . A method according to  claim 36  wherein reducing the transverse cross-section of said elongated molding core comprises melting said core.  
     
     
         39 . A method according to  claim 36  wherein reducing the transverse cross-section of said elongated molding core comprises dissolving said core.  
     
     
         40 . A method according to  claim 34  wherein said step of removing said molding core from said coated tubular element comprises pulling said molding core longitudinally out of said coated tubular element.  
     
     
         41 . A method according to  claim 34  comprising the further steps of, prior to step (d), forming at least one side opening through said tubular element in proximally-spaced, proximate relation to the distal end thereof, and inserting a molding pin therein.  
     
     
         42 . A method according to  claim 34  comprising the further step of, prior to step (d), locating a support structure at the distal end of said tubular element.  
     
     
         43 . A method for the dialysis of the blood of a patient, said method comprising the steps of: 
 (a) providing a dialysis machine, and providing apparatus comprising a connector portion and a catheter portion; 
 said connector portion comprising an outlet adapted for communication with a line connected to the input port of said dialysis machine, and an inlet adapted for communication with a line connected to the output port of said dialysis machine; and  
 said catheter portion comprising a catheter element comprising: 
 a suction line and a return line, each said line comprising a flexible tubular element, said tubular element having an open proximal end, an open distal end and a side wall defining a lumen extending between said open proximal end and said open distal end, said side wall (1) being formed of a biocompatible material, (2) encasing a reinforcing means therein for reinforcing said side wall, and (3) having a smooth interior surface for defining said lumen, said smooth interior surface being sufficiently smooth that said tubular element may be used for hemodialysis applications with good results;  
 said proximal end of said suction line being connected to said connector portion and in communication with said outlet, and said distal end of said suction line terminating in a suction line mouth;  
 said proximal end of said return line being connected to said connector portion and in communication with said inlet, and said distal end of said return line terminating in a return line mouth;  
 said suction line and said return line being adapted for disposition within the body of the patient so that said suction line mouth and said return line mouth are both disposed in the vascular system of the patient;  
 
   (b) placing said suction line mouth and said return line mouth in the vascular system of the patient;    (c) connecting said outlet to the input port of said dialysis machine, and connecting said inlet to the output port of said dialysis machine; and    (d) operating said dialysis machine.    
     
     
         44 . A method according to  claim 43  wherein said connector portion comprises an extracorporeal connector element attached against an outside surface of the body of the patient.  
     
     
         45 . A method according to  claim 43  wherein said connector portion comprises a subcutaneous port element implanted within the body of the patient.  
     
     
         46 . A method according to  claim 43  wherein, in step (a), said suction line and said return line are field trimmed to size prior to being connected to said connector portion.  
     
     
         47 . A catheter comprising at least one flexible tubular element, said at least one tubular element having an open proximal end, an open distal end and a side wall defining a lumen extending between said open proximal end and said open distal end, said side wall being formed of a biocompatible material and having a smooth interior surface for defining said lumen, said smooth interior surface being sufficiently smooth that said at least one tubular element may be used for hemodialysis applications with good results, and said catheter further comprising a support structure attached to said side wall adjacent to said open distal end of said at least one flexible tubular element.  
     
     
         48 . A method according to  claim 34  wherein said step of removing said molding core from said coated tubular element comprises blowing said molding core longitudinally out of said coated tubular element.  
     
     
         49 . A catheter according to  claim 1  wherein said reinforcing means comprise a tubular, braided mesh reinforcer.