US 6,206,851 B1 · Hemodialysis access apparatus

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.

Claims40

Dependent claims

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.

3 more elements

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.

5 more elements

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.

3 more elements

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.

2 more elements

Dependencies are inferred from the claim text.

Hemodialysis access apparatus

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Hemodialysis access apparatus

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Abstract

Claims40