Hemodialysis access apparatus

• US 6,206,851 B1
• Filed: 05/21/1998
• Issued: 03/27/2001
• Est. Priority Date: 06/07/1995
• Status: Expired due to Fees

• Current Assignee: ND Partners LLC
• Original Assignee: Biolink Corp. (Acacia Capital Corp.)
• Inventors: Prosl, Frank R.
• Primary Examiner(s): Brown, Michael A.
• Application Number:
  US09/083,078
• Time in Patent Office: 1,041 Days
• Field of Search: 604/891.1, 604/256, 604/93, 604/167, 604/175
• US Class Current: 604/93.01
• CPC Class Codes: A61M 1/16 with membranes
• CPC Class Codes: A61M 1/3653 Interfaces between patient blood circulation and extra-corporal blood circuit
• CPC Class Codes: A61M 1/3659 Cannulae pertaining to extracorporeal circulation
• CPC Class Codes: A61M 2039/0258 for vascular access, e.g. blood stream access
• CPC Class Codes: A61M 2039/027 having a particular valve, seal or septum septum A61M2039/0036
• CPC Class Codes: A61M 2039/0276 for introducing or removing fluids into or out of the body
• CPC Class Codes: A61M 2039/062 used with a catheter
• CPC Class Codes: A61M 2039/0673 comprising means actively pressing on the device passing through the seal, e.g. inflatable seals, diaphragms, clamps
• CPC Class Codes: A61M 39/0208 Subcutaneous access sites for injecting or removing fluids transcutaneous access sites A61M39/0247; implantable infusion devices A61M5/14276
• CPC Class Codes: A61M 39/0247 Semi-permanent or permanent transcutaneous or percutaneous access sites to the inside of the body peritoneal dialysis catheters A61M1/285; tracheostomy devices A61M16/0465; measuring pressure within the body A61B5/03; colostomy devices A61F5/445; gastrotomy feeding tubes A61J15/0015; means for fixing a feeding tube outside of the body A61J15/0053
• CPC Class Codes: A61M 39/0613 with means for adjusting the seal opening or pressure A61M39/0693 takes precedence
• CPC Class Codes: A61M 39/228 with a tubular diaphragm constrictable by radial fluid force

Abstract

An implanted single or dual lumen device for repeated accessing of a vessel within a body, especially for hemodialysis, plasmapheresis, and other fluid exchange therapy treatments. The device is characterized by having: no septum for sealing but having instead a resilient material to form a seal; a smooth, streamlined flowpath with low flow resistance and substantially no stagnation points, such that the device is easily and completely flushed; optionally a gradually changing direction of flow path without introducing flow resistance or stagnation points with a change in direction of up to 20 degrees with a minimum bend radius of twice the lumen diameter or up to 30 degrees with a minimum bend radius of four times the lumen diameter; and a positive locking mechanism that accepts and retains a matching needle apparatus. The device is joined to a catheter, in most cases, such that fluids can be extracted from or injected into the vessel or vessels to be accessed. The device is designed for the high flow rates, on the order of 400 milliliters per minute, associated with hemodialysis, plasmapheresis, and other fluid exchange therapies. A corresponding needle apparatus is designed to mate and lock with the access device, where alignment and open flow path is ensured. The needle apparatus first penetrates the skin and then the access device via the seal. The access device is flexibly mounted to the body at the attached catheter allowing the device itself to move under the skin so as to accommodate and align with the needle apparatus.

Claims

1. A hemodialysis access system for access to a human or animal patient'"'"'s vascular system for high fluid flow rate exchange of blood between the vascular system and an external processing apparatus at a volumetric flow rate in excess of 250 ml/minute, and comprising, in combination,

(a) a needle assembly comprising a lumen defined by an interior surface and constructed and arranged for puncturing the skin of the patient and for carrying blood therethrough at a flow rate consistent with high blood flow requirement of the blood exchange process;

(b) a subcutaneously implantable access device permitting fluid connection to a vessel or space within a patient'"'"'s body, the device comprising;

(i) a channel structure providing a flowpath having a gently changing flow direction and having an interior surface and a distal end and a proximal end with reference to the patient'"'"'s skin puncture site and constructed and arranged for insertion of the needle through the proximal end of the channel and withdrawal of the needle therefrom,

(ii) a seal arranged within the channel and movable between first and second positions, where said seal, in said first position, with said needle not inserted through said seal, prevents fluids from passing said seal and, in said second position, with said needle inserted through said seal, allows fluids to pass through said needle and emerge substantially at said channel distal end, and where blood flowpath transitions between said needle interior surface and said channel interior surface are substantially continuous and smooth when said means for sealing is in said second position; and

the device further comprising structure for joining said channel distal end to a catheter that extends to an internal vessel of the patient'"'"'s body, and wherein such joining is continuous and smooth along said interior surfaces of the channel and catheter.

2. The access system of claim 1 further comprising:

(c) a catheter constructed and arranged for implantation between said device at a proximal catheter end and to or into a patient'"'"'s blood vessel at a distal catheter end, and

(d) means for attaching the catheter to the surrounding patient tissue, said attachment allowing movement of the catheter'"'"'s proximal end and of said device.

3. The access system of claim 1 wherein said gently changing flow direction comprises a bend angle that is less than or equal to about 30 degrees having a bending radius greater than or equal to about two times the diameter of the flowpath.

4. The access system of claim 3 wherein the flowpath diameter is in the range from about 0.060 to about 0.105 inch.

5. The access system of claim 1 wherein said gently changing flow direction comprises a bend angle that is less than or equal to about 20 degrees having a bending radius greater than or equal to about four times the diameter of the flowpath.

6. The access system of claim 5 wherein the flowpath diameter is in the range from about 0.060 to about 0.105 inch.

7. The access system of claim 1 wherein said needle has a lumen and disposed along a first axis, said needle matingly corresponding to the inner surface and having a wall thickness of approximately 0.1 mm,

and an obturator that is disposed within the needle along the first axis and matingly inserted into the lumen of said needle, said needle and obturator designed to provide an assembly with a pointed end constructed for opening said means for sealing, and means defining an access channel external to the patient communicating with the lumen of said needle, when it is inserted into the patient and through said means for sealing and wherein said access channel is disposed at an acute angle from said needle first axis.

8. The access system of claim 7 further comprising a groove constructed in the outer surface of said needle, and a needle lock located within the channel length and extending into the channel, said needle locking means positioned before the means for sealing, said needle lock engaging said needle groove to secure the needle to the access housing, and wherein said channel and needle lock are constructed to release by twisting and/or pulling on the needle out of the channel.

9. The access system of claim 1 for high flow rate blood exchange between a human or animal patient with simultaneous flow in and out of the patient through separate paths, comprising a subcutaneously implantable access devise capable of being implanted in the patient just under the skin and having two passages therein, each with an entrance proximal to the skin and an exit distal therefrom, for accommodating two hollow needles, with interior lumens, percutaneously inserted therein, the transitions between the interior lumens of the needles and passage interiors of the device having gentle changes in flow direction and streamlined flowpaths, thereby permitting fluid connection to one or two blood vessels within a patient'"'"'s body.

10. The access system of claim 9 further comprising means to secure said needles to each other and locking means to secure the needles within the device.

11. A hemodialysis access system for use in a blood exchange therapy system, involving an extracorporeal blood processing apparatus operating at a flowrate of at least 250 milliliters per minute and being capable of allowing hundreds of such therapy cycles,

the blood exchange therapy system comprising a catheter implanted in the patient and connected to a blood vessel of the patient at a distal end and having a proximal portion within the patient adjacent the patient'"'"'s skin, and

the access system comprising:

(a) means forming a continuous, streamlined flowpath running from outside the patient to the catheter, essentially free of surface discontinuities and flow stagnation sites and substantial pressure drops, said means comprising a channel structure providing a flowpath having gentle changes in flow direction, and said means having two elements joining at an abutment with smooth transition at such abutment and all changes in flowpath cross-section being of a gradual nature, said means comprising;

(i) a device implantable within the patient and having a passage therein;

(ii) a needle that is insertable percutaneously into the patient and into the device passage to establish a portion of the flowpath and is withdrawable from the device and the patient; and

(iii) a flexible seal in the device that automatically blocks the flowpath when the needle is not inserted and is entirely out of the flowpath when the needle is inserted and is not degraded by the repetitive therapy cycles of needles insertion, high volume blood exchange and needle withdrawal,

whereby a blood exchange therapy is maintainable with high resistance to blood clotting, infection, erythrocyte damage and platelet activation and with low pressure drop along the flowpath, consistent with the flow requirements of blood exchange therapy.

12. The hemodialysis access system of claim 11 further comprising a distal catheter wherein the device is freely movable and the distal catheter is secured to surrounding tissue.

13. The hemodialysis access system of claim 11 wherein said gently changing flow direction comprises a bend angle that is less than or equal to about 30 degrees and a bending radius greater than or equal to about two times the diameter of the flowpath.

14. The hemodialysis access system of claim 13 wherein the flowpath diameter is in the range from about 0.060 to about 0.105 inch.

15. The hemodialysis access system of claim 11 wherein said gently changing flow direction comprises a bend angle that is less than or equal to about 20 degrees and a bending radius greater than or equal to about four times the diameter of the flowpath.

16. The hemodialysis access system of claim 15 wherein the flowpath diameter is in the range from about 0.060 to about 0.105 inch.

17. A hemodialysis access system for repeated access to a patient'"'"'s distal vascular system in the course of long term fluid exchange therapy between the vascular system and a proximal blood processing site, via a catheter that is subcutaneously implanted in the patient and has a distal end coupled to a patient blood vessel and a proximal end, the system comprising, in combination,

(a) a needle assemble comprising an elongated thin walled rigid cannula with ends proximal toward the blood processing site and distal toward the vascular system and an obturator constructed and arranged for insertion into the cannula and passing through its full length, and with a pointed distal end of the obturator emerging from a cannula distal end and removable from the cannula, the cannula being constructed and arranged, when the obturator is removed, for blood flow through the cannula interior at a high flow rate of at least 250 milliliters per minute, the cannula being constructed at its distal end for longitudinal flow of blood at such end to enter or exit the cannula and means for communicating from said back end portion of the cannula interior to an external blood processing site,

(b) a subcutaneously implantable access device having an entrance and exit regions and a passage therebetween which permits the cannula to enter the entrance end region and occupy a substantial passage length with a smooth transition between said cannula distal end and the device'"'"'s exit region, the device being arrangeable subcutaneously with its exit region attached to said proximal catheter end and its entrance region accessible to the needle assembly through the patient'"'"'s skin, the cannula interior and exit region thereby defining together a continuous streamlined flowpath having gently changing flow direction and essentially free of stagnation points or abrupt transitions and constructed and arranged for blood passage through the flow path defined thereby at a flow rate of at least 250 milliliters per minute,

(c) the needle assemble being constructed and arranged to penetrate the patient'"'"'s skin and subcutaneous tissue to reach the entrance region of the said device and transit the passage of the latter to a point adjacent the exit region of the device and for withdrawal of the obturator to a point external of the patient'"'"'s skin whereby the external blood processing site can be placed in fluid communication with the cannula and catheter to establish a blood exchange path, and flushing path, from outside the patient to the patient'"'"'s vascular system,

 

and further comprising,

(d) a seal located within the device'"'"'s passage at a site normally passed by cannula/obturator insertion therein, and comprising means to close off the passage, when acted on by a biasing force, to produce a seal seating stress when the cannula/obturator is not in the passage and openable when contacted by the cannula/obturator constructed and arranged so that the external cannula/obturator surfaces bear against the means to force it aside to an open position, overcoming the bias force, to permit the cannula/obturator to transit the device'"'"'s passage, but without the obturator distal point contacting the resilient sealing material,

the cannula being sufficiently rigid to hold the seal open when the obturator is withdrawn from the inserted needle.

18. The access system of claim 17 wherein said gently changing flow direction comprises a bend angle that is less than or equal to about 30 degrees and a bending radius greater than or equal to about two times the diameter of the flowpath.

19. The access system of claim 18 wherein the flowpath diameter is in the range from about 0.060 to about 0.105 inch.

20. The access system of claim 17 wherein said gently changing flow direction comprises a bend angle that is less than or equal to about 20 degrees and a bending radius greater than or equal to about four times the diameter of the flowpath.

21. The access system of claim 20 wherein the flowpath diameter is in the range from about 0.060 to about 0.105 inch.

22. The access system of claim 17 further comprising a needle-locking means to secure a percutaneously inserted needle within the device.

23. The access system of claim 17 wherein the passage comprises a region adjacent its exit for docking with the distal end of the inserted cannula and forming a smooth walled flow path transition therewith.

24. A hemodialysis access system comprising:

(a) means for providing a continuous flowpath, crossing a patient'"'"'s skin, between and external-to-patient dialysis site and an internal blood vessel of the patient, said means including a flow conduit having gentle changes in direction and whose internal surfaces are smooth and free of abrupt changes in flow area and define a flowpath sized for hemodialysis flow rates, and free of obstructions to provide low flow resistance and avoid stagnation point;

(b) means for blocking the flowpath at a point under the patient'"'"'s skin; and

(c) means for removing the flowpath portion crossing the patient'"'"'s skin;

to allow closure and healing of the skin crossing site.

25. The system of claim 24 further comprising a flexible seal and wherein flowpath blockage is provided by said flexible seal, the flexible seal being entirely removable from the flowpath to establish a fully open configuration thereof free of obstructions and abrupt flow diameter or flow direction changes.

26. The system of claim 24 wherein said gently changing flow direction comprises a bend angle that is less than or equal to about 30 degrees and a bending radius greater than or equal to about two times the diameter of the flowpath.

27. The system of claim 26 wherein the flowpath diameter is in the range from about 0.060 to about 0.105 inch.

28. The system of claim 24 wherein said gently changing flow direction comprises a bend angle that is less than or equal to about 20 degrees and a bending radius greater than or equal to about four times the diameter of the flowpath.

29. The system of claim 28 wherein the flowpath diameter is in the range from about 0.060 to about 0.105 inch.

30. The system of claim 24 and further comprising means for locking and unlocking the flowpath forming portion of the system.

31. The system of claim 24 and further comprising means for increasing the available skin-crossing sites used in establishing the flowpath.

32. The system of claim 31 comprising a hollow needle which is insertable percutaneously by longitudinal pushing of it to a site where it defines a portion of said flowpath, and withdrawable by longitudinal pulling of said needle, and an implanted catheter comprising another portion of the flowpath and means for establishing a smooth continuous transition between said portions.

33. The system of claim 32 further comprising means for locking the inserted needle in place wherein said locking means is constructed and arranged to lock the needle upon longitudinal withdrawal movement accompanied by a lateral twisting movement.

34. The system of claim 33 further comprising an obturator within the hollow needle wherein said obturator has a pointed end arrangeable to protrude from a hollow needle end.

35. A hemodialysis access system for repeated access to a patient'"'"'s vascular system, for hemodialysis repetitive blood exchange therapy, via a catheter that is subcutaneously implanted in the patient and has a distal end attached to a patient blood vessel and a proximal end near the patient'"'"'s skin, the system comprising, in combination,

(a) a subcutaneously implantable access device having an entrance region, exit region and a passage therebetween provide for introduction of a needle thereby defining together with each other and the catheter a continuous streamlined flow path having gentle changes in flow direction and essentially free of stagnation points and constructed and arranged for blood flow through the flow path at a flow rate of at least 250 milliliters per minute,

(b) a needle for defining a continuous flowpath extension relative to the catheter and with a front part of the obturator emerging from a cannula front end and removable from the cannula, the cannula being constructed and arranged as a passage, when the obturator is removed, and means for communicating from the distal end of the cannula interior to an external patient site,

(c) the needle being constructed and arranged to puncture the patient'"'"'s skin, to penetrate subcutaneous tissue and reach the entrance region of the implanted device and transit the passage of the latter to a point adjacent the exit region of the device and for withdrawal of the obturator of the needle means to thereby establish fluid communication between an external to the patient site and the catheter to provide a blood exchange path and flushing path from outside the patient to the patient'"'"'s vascular system,

 

and further comprising,

(d) means located within the device'"'"'s passage at a site normally passed by needle insertion therein, for sealing said passage when the cannula/obturator is not in the passage and openable when contacted by the outer surface of the needle means, the seal and needle constructed and arranged so that the needle surface bears against the sealing material which is forced aside to an open position to permit the needle to transit the devices'"'"'s passage, but without the point thereof contacting the sealing surfaces, the cannula being sufficiently rigid to hold the seal open when the obturator is withdrawn from the inserted cannula.

36. The hemodialysis access system of claim 35 wherein said gently changing flow direction comprises a bend angle that is less than or equal to about 30 degrees and a bending radius greater than or equal to about two times the diameter of the flowpath.

37. The hemodialysis access system of claim 36 wherein the flowpath diameter is in the range from about 0.060 to about 0.105 inch.

38. The hemodialysis access system of claim 35 wherein said gently changing flow direction comprises a bend angle that is less than or equal to about 20 degrees and a bending radius greater than or equal to about four times the diameter of the flowpath.

39. The hemodialysis access system of claim 38 wherein the flowpath diameter is in the range from about 0.060 to about 0.105 inch.

40. The system of claim 35 wherein the passage comprises a region adjacent its exit for stopping the front end of the cannula of the inserted needle and forming a smooth walled flow path transition therewith.