Catheter system with attachable catheter hub

A hemodialysis catheter assembly adapted for use in a subcutaneous tunneling procedure incorporates a mechanism for securing the catheter hub member to the elongated catheter, and to provide the requisite fluid communication between fluid passages within the hub and the catheter lumens within the catheter. The catheter hub member may be connected to the elongated catheter after implantation of the catheter via a subcutaneous tunneling procedure.

BACKGROUND

1. Technical Field

The present disclosure is directed to a catheter assembly, and, in particular, relates to a catheter system adapted for use in a subcutaneous tunneling catheterization procedure. The present disclosure further relates to catheter hubs or housing mechanisms which are selectively attachable to an elongated catheter tube either prior, to or subsequent to, implantation of the catheter tube during a hemodialysis procedure.

2. Description of the Related Art

Catheters are flexible medical instruments intended for the withdrawal and introduction of fluids relative to body cavities, ducts, and vessels. Catheter instrumentation may have particular application in a hemodialysis procedure where blood is withdrawn from a blood vessel for treatment, and subsequently returned to the blood vessel for circulation. Known hemodialysis catheters include multiple lumens, such as dual lumen or triple-lumen catheters, permitting bi-directional fluid flow within the catheter whereby one lumen is dedicated for withdrawal of blood and the other lumen is dedicated for returning the treated blood to the vessel. During an exemplary hemodialysis procedure, a multiple lumen catheter is inserted into a body and blood is withdrawn through an arterial lumen of the catheter. The removed blood is directed to a hemodialysis unit which dialyzes, or purifies, the blood to remove waste, and toxins. The dialyzed blood is returned to the patient through a venous lumen of the catheter.

Various techniques are employed for the insertion of hemodialysis catheters including, e.g., with the use of guidewires, introduction stylets or the like. Some of these known techniques include subcutaneous tunneling methodologies where a subcutaneous tunnel is formed between two spaced openings in the skin with the use of a trocar or the like. One catheter end is introduced through an entry site or venotomy site for routing into, e.g., the jugular vein and routed to the heart. The trailing or proximal end is advanced through the subcutaneous tissue to exit a second exit opening adjacent the sternum of the patient beneath the venotomy site. Once the proximal end of the catheter is exposed, a catheter hub with extension tubes is fluidly connected to the catheter. One subcutaneous technique is disclosed in U.S. Pat. No. 5,509,897 to Twardowski et al., the contents of which is incorporated herein by its entirety.

SUMMARY

Accordingly, the present disclosure is directed to a hemodialysis catheter assembly adapted for use in a subcutaneous tunneling procedure. Various embodiments of the hemodialysis catheter assembly are disclosed. Each embodiment of the catheter assembly incorporates a mechanism for securing the catheter hub member to the elongated catheter, and to provide the requisite fluid communication between fluid passages within the hub and the catheter lumens within the catheter. The catheter hub member may be connected to the elongated catheter after implantation of the catheter via a subcutaneous tunneling procedure.

DETAILED DESCRIPTION OF THE EMBODIMENTS

The exemplary embodiments of the catheter systems and methods of use disclosed are discussed in terms of medical catheters for the administration of fluids (withdrawal or introduction) relative to the body of a subject and, more particularly, in terms of a hemodialysis catheter. However, it is envisioned that the present disclosure may be employed with a range of catheter applications including surgical, diagnostic and related treatments of diseases and body ailments of a subject. It is further envisioned that the principles relating to the catheter disclosed include employment with various catheter related procedures, such as, for example, hemodialysis, cardiac, abdominal, urinary, intestinal, and in chronic and acute applications. Moreover, the catheter can be used for administration of fluids such as, for example, medication, saline, bodily fluids, blood and urine.

In the discussion that follows, the term “proximal” or “trailing” will refer to the portion of a structure that is closer to a clinician, while the term “distal” or “leading” will refer to the portion that is further from the clinician. As used herein, the term “subject” refers to a human patient or other animal. The term “clinician” refers to a doctor, nurse or other care provider and may include support personnel.

The following discussion includes a description of the catheter system, followed by a description of an exemplary method of operating the catheter in accordance with the principles of the present disclosure. For discussion purposes, the catheter will be discussed in terms of a hemodialysis catheter and the method of operation will be discussed in terms of a reverse tunneling procedure utilized for positioning the catheter during a dialysis procedure. However, those skilled in the art will appreciate the catheter has many other applications in addition to dialysis applications.

Referring now to the FIGURES wherein like components are designated by like reference numerals throughout the several views,FIGS. 1-4illustrate in perspective views, the hemodialysis catheter10in accordance with the principles of the system of the present disclosure. Catheter10includes several components assembled together, namely, catheter hub or housing12and elongated catheter tube or member14extending distally from the catheter hub12. In general, catheter hub12is attachable to catheter member14subsequent to implantation of the catheter member14relative to the patient during a medical procedure such as, e.g., a hemodialysis procedure. Various mechanisms for attaching catheter hub12to catheter tube are contemplated by the present disclosure and will be described in greater detail hereinbelow.

Catheter hub12is advantageously dimensioned for engagement by the clinician. Catheter hub12includes proximal or trailing housing section18and distal or leading housing section20adjacent catheter members14. Trailing housing section18is connectable to extension tubes (not shown) through extension tube mounts15, which serve as the venous and arterial lines leading to the hemodialysis machine as is conventional. Leading housing section20defines an annular collar22. Annular collar22has internal lumens23in fluid communication with fluid passages25extending through catheter hub12. Internal lumens23may be generally D-shaped. Other configurations are also envisioned. Annular collar22may be formed of a compressible material. Catheter hub12may further include a pair of opposed suture wings24along its outer surface. Suture wings24define openings26dimensioned for receiving sutures which may be utilized in securing catheter hub12relative to the subject. In an alternative embodiment, catheter hub12may have an annular groove (not shown) in its outer wall in lieu of suture wings24. A suture may be wrapped within annular groove and subsequently secured relative to the subject.

Catheter member14may be any catheter tube suitable for use with a desired medical procedure. Catheter member14may be single, dual or triple lumen catheters. In the embodiment shown inFIG. 1, catheter member14is a dual lumen catheter having particular application in a hemodialysis procedure. However, catheter member14may be any commercial available catheter member such as the catheter members sold under the trademarks Palindrome and Mahurkar. In this regard, catheter member14has first and second longitudinal lumens28,30separated by a septum wall32which extends the length the catheter tube. Each of the first and second longitudinal lumens28,30may define a D-shaped opening in cross-section. Other lumen arrangements are also envisioned including circular, pie shaped or other shapes known in the art. Coaxial lumens are also envisioned. Leading or distal end34of catheter member14may have various configurations. In one embodiment, the arrangement of catheter distal end34is similar to an embodiment disclosed in commonly assigned U.S. Patent Publication No. 2005/0267400 to Haarala et al., filed Feb. 11, 2005, the entire contents of which is incorporated herein by reference. Other arrangements, e.g., as disclosed as alternate embodiments in the Haarala '400 publication, are also envisioned.

Catheter member14is preferably flexible and may be formed by conventional injection molding or extrusion means. The wall of catheter member14may include reinforcing material if desired. Catheter member14may have a pre-curved configuration in its normal state, i.e., have a preformed bend which it normally assumes in the absence of an external stressor to conform to a body cavity or vessel in which the catheter member is to be positioned. Alternatively, catheter member14may be devoid of any normally curved orientation.

Referring still toFIGS. 1-4, hub attachment mechanism will be discussed. Hub attachment mechanism36includes multiple tube connector38and at least one, preferably, two locking collars40. Multiple tube connector includes two connector tubes42and connector collar44. Connector collar44includes two openings therethrough which accommodate connector tubes and maintains the connector tubes42in side by side but slightly spaced relation. Connector collar44may be secured to connector tubes42if desired. Connector tubes42each define a cross-section which generally approximates the cross-section of lumens of catheter member14and internal passages within catheter hub12. In one embodiment, the cross-section of connector tube is generally D-shaped to at least correspond to the D-shaped arrangement of catheter member.

Locking collars40are each split into two substantially equal half rings40a,40b. Means for connecting half rings are envisioned. In one embodiment, one half ring40aof locking collar40includes at least one locking projection46which is receivable in a corresponding recess(es)48of the opposed locking ring40bin snap relation to secure the half rings together. Other means for securing half rings40a,40bare also envisioned including with the use of cements, adhesives, tongue-groove arrangement or the like. Half rings40a,40bof locking collars40may be connected together through a hinge or the like or connected by a tether.

Upon assembly of catheter hub12to catheter member14when, e.g., catheter member14is appropriately positioned relative to the body, connector tube assembly38is first positioned within catheter member14with catheter tube ends of the first and second tubes42being received within respective lumens of the catheter. Preferably, proximal end of catheter member14is advanced along catheter tube ends until the proximal face of catheter contacts connector collar44. Similarly, hub tube ends of connector tubes42are positioned within internal passages of catheter hub12and the catheter hub12is advanced along the catheter tube ends. Thereafter, half rings40a,40bof one locking collar40are positioned about proximal end14pof catheter member14and the half rings40a,40bof the second collar40are positioned about hub mounting collar22of catheter hub14. Each of respective half rings40a,40bis snapped together to the condition depicted inFIG. 1. In this position, locking collar40compresses proximal end14pof catheter member14against catheter tube ends of connector tubes42and locking collar40compresses mounting collar22of catheter hub12against hub tube ends of connector tubes42. With this arrangement, a compressive frictional relationship is established between locking collars40and respective proximal end14pof catheter tube14and hub mounting collar22to thereby secure catheter member14and catheter hub12to connector assembly38and attaching catheter hub12to catheter member14. It is also envisioned that half rings40a,40bof locking collars40may be integrally, or monolithically, formed as a single unit resembling a clam shell arrangement. Half rings40a,40bcould fold along hinges to assume the locked position around catheter hub12and catheter member14.

FIGS. 5-7illustrate an alternate embodiment of the hub attachment mechanism ofFIGS. 1-4. In accordance with this embodiment, locking collars are replaced with single elongate locking sleeve which is coaxially positionable about the proximal end of catheter member. Connector assembly is similar to the connector assembly ofFIGS. 1-4, with connector tubes being positioned within lumens of catheter member and passages of catheter hub12in the manner discussed hereinabove. Locking sleeve50is fabricated from a suitable elastomeric material such that it may stretch when positioned over the proximal end14pof catheter member14and hub mounting collar22of catheter hub12. Locking sleeve50is advanced in a proximal direction toward catheter hub12which causes internal surfaces52of locking sleeve50to compress the proximal end14pof catheter member14against connector tube end in frictional relation therewith. In one embodiment, the internal bore of locking sleeve50is less in dimension or diameter than the cross-sectional dimension of connector ends of connector tubes42requiring the locking sleeve50to stretch over the connector tubes42. The proximal end of locking sleeve50is continually advance toward catheter hub12to be positioned about peripheral ribs54of the catheter hub12. Peripheral ribs54also serve to secure locking sleeve50to catheter hub12. As best depicted inFIG. 6, locking sleeve50may compress the proximal end14pof catheter member14tube and/or hub mounting collar22to secure connector tubes42, catheter member14and catheter hub12. Connector tubes42may also possess raised protrusions58on its outer surface on both connector end and hub end of the tubes42to facilitate the frictional relationship between the components. The elastomeric characteristics of locking collar50may facilitate the establishment of a seal about the catheter member.

FIGS. 8-9illustrates another embodiment of catheter system. In accordance with this embodiment, an elastomeric grommet60is mounted or molded about connector tubes42. The elastomeric grommet60includes first collar segment60aand second collar segment60b. First collar segment60adefines a cross-sectional dimension that is greater than the cross-sectional dimension of second collar segment60b. Connector tubes42are positioned within the catheter hub12and catheter member14is mounted about the connector tubes42and advanced to the collar or grommet60. Catheter hub12includes mounting collar62having an external threaded portion64. Collar segment60bof the elastomeric grommet60is dimensioned for reception within an internal bore63of mounting collar62. Second collar segment60bengages the internal surfaces of mounting collar62and may create a seal therein. Locking sleeve66incorporates corresponding internal threaded68(shown in cut-away) adjacent its proximal end. Once connector assembly is positioned with respect to lumens of catheter member14and internal passages of catheter hub12, locking sleeve66and catheter member14are advanced toward catheter hub12to approximate locking sleeve66and mounting collar62of the catheter hub12. Thereafter, locking sleeve66is rotated whereby the corresponding threaded components64,68of locking sleeve66and mounting collar62cooperate to secure the locking sleeve66to catheter hub12. Locking sleeve66may have an internal dimension to compress elastomeric first collar segment60aof grommet60thereby creating an interference relationship between the locking sleeve66and connector tubes42and also facilitating the formation of a seal within catheter hub12.

FIGS. 10-11illustrate another embodiment of the present disclosure. In accordance with this embodiment, catheter hub70incorporates mounting collar72which possesses first and second longitudinal grooves74arranged in opposed relation. Catheter hub70also incorporates first and second hypo tubes76which may be fixed within the catheter hub70. Locking sleeve78mounted about catheter member14incorporates first and second axially depending locking tabs80. Locking tabs80each incorporate locking detents82. Upon assembly, locking tabs80are positioned within first and second longitudinal grooves74of catheter hub70with locking detents82of the locking tabs80securely engaging proximally facing shelves84of mounting collar72to secure locking sleeve78and catheter hub70. Locking sleeve78may incorporate internal structure to compress the proximal end of catheter14against the hypo tubes. Alternatively, the lumens of catheter member14may be dimensioned to form a friction fit about the hypo tubes76. Locking sleeve78and/or locking tabs80may be rigid such that securement of the locking tabs80to the catheter hub70may be irreversible. This may prevent disconnection by the patient.

FIGS. 12,12A and13illustrate another embodiment generally similar to the embodiment ofFIGS. 10-11. However in accordance with this embodiment, a compressible member or ring90is positioned about the proximal end of catheter member14prior to securement of locking sleeve78. Compressible ring90is preferably made of spring metal or the like and has a plurality of radially spaced deflectable elements91. Each deflectable element91has edge92which may engage the proximal end of catheter member14to assist in securing catheter member14to the hypo tubes76. Compressible ring90is deflected inwardly during securement of locking sleeve78to catheter hub12as best depicted inFIG. 12Athrough engagement of outer ramp surfaces94of the deflectable elements91and the interior of locking sleeve78.

FIG. 12Bshows an alternate embodiment with a deflecting ring93positioned around the proximal end of the catheter14. The deflecting ring93compresses and seals the catheter14once locking sleeve78is advanced in a proximal direction toward the catheter hub70. The radial compression exerted by the deflecting ring93on the catheter14grips the catheter14to the first and second hypo tubes76, thereby retaining the catheter14connected to the catheter hub70. Deflecting ring93includes ring collar93aand compressing segment93bextending from the ring collar93a. Compressing segment93bincludes axial slots93cwhich permit inward deflection of the compressing segment93b. Ring collar93amay have a recess93dfor receiving a corresponding tab72aof mounting collar72of catheter hub70. This arrangement may facilitate securement of deflecting ring93relative to catheter hub70.

FIGS. 14-16illustrate another embodiment of the catheter hub attachment mechanism. In accordance with this embodiment, hypo tubes or connector tubes90are mounted to extend from catheter hub92. Catheter member14is advanced over the connector or hypo tubes90to essentially abut against the distal face of catheter hub92. Locking sleeve94is pushed or advanced over the proximal end14pof catheter member14whereby locking detent96of the locking sleeve94engages corresponding annular ridge98of catheter hub92to secure the locking sleeve94to the catheter hub92. As a further feature, the internal surface of locking sleeve94may incorporate interference areas100which extend radially inwardly. The interference areas100serve to compressibly engage the outer surface of catheter member14to establish an interference relation therewith. Locking sleeve94may be formed of a suitable elastomeric material to expand and contract to permit positioning over catheter hub.

FIGS. 17-19illustrate another embodiment of the hub attachment mechanism. Catheter hub110includes tapered mounting collar112and annular shelf114adjacent a proximal end of the mounting collar112. Locking sleeve116incorporates several components which permit releasable attachment of locking sleeve116to catheter hub110. Specifically, locking sleeve116includes outer locking member118and inner locking member120. Outer member118may be elastomeric and encloses inner member120and the proximal end14pof catheter member14. Outer member118may have an internal annular detent122at its trailing end which is received within a corresponding outer annular recess124of catheter hub110to secure the outer member120to the catheter hub110. Inner member112includes opposed locking legs124which are interconnected by partial ring126extending between the legs124. Locking legs124are adapted for pivotal movement relative to rings126upon depression of leading leg elements124l. This action will cause trailing leg elements124tto pivot radially outwardly out of engagement with corresponding locking recesses128in mounting collar112of catheter hub110. In use, catheter member14is positioned about the hypo or connecting tubes extending from catheter hub112. Thereafter, locking sleeve116is advanced to resiliently and/or frictionally engage the outer surface of catheter member14. When appropriately positioned, trailing or proximal leg elements124tare positioned whereby locking detents130of the leg elements are received within locking recesses128of mounting collar120. Similarly, internal annular detent122of outer member118is secured within annular recess124of catheter hub110. With this arrangement, locking sleeve116and catheter member14are secured to catheter hub110. When it is desired to release catheter hub110from catheter member14, outer member118is depressed adjacent finger grooves134which causes engagement with the leading or distal leg elements124lof locking legs124. Further squeezing movement causes, proximal or trailing leg elements124tto pivot outwardly and become released from locking recesses128. Catheter member14may then be moved from catheter hub110.

FIGS. 20-22illustrate another alternate embodiment of the catheter hub attachment mechanism. In accordance with this embodiment, locking sleeve150includes first152and second series154of internal threads. The first series152is adapted to threadably engage the outer threaded surface156of mounting collar of catheter hub158. The second series154engages the proximal end of catheter tube14when the locking sleeve150is secured to the catheter hub158. In one aspect of this embodiment, hypo tubes160extending from catheter hub158may be slightly larger in diameter or dimension than internal lumens of the catheter14. Thus upon passage of the catheter proximal end14pover the respective hypo tubes160, the catheter must stretch to some degree to accommodate the hypo tubes160. Thus upon securing of locking sleeve150, the second series of threads154more readily bites into the catheter proximal end14psecuring the catheter14relative to the hypo tubes and the hub.

FIGS. 23-25illustrate another embodiment which is substantially similar to the prior embodiment. In accordance with this embodiment, however, the connection tubes or hypo tubes define a dimension which increases in cross section toward catheter hub, i.e., has an outward flare adjacent catheter hub. This configuration may facilitate initial positioning of proximal catheter end onto the connection tubes whereby upon continued movement toward catheter hub, the wider dimension of the hypo tubes contacts the proximal end of the catheter, e.g., in frictional engagement therewith. In addition, upon tightening of locking sleeve, the internal threads in effect obtain a larger bite of the catheter adjacent catheter hub at the flared areas further securing the catheter on the hub.

FIG. 26has an alternate embodiment of catheter hub which may be utilized with the embodiments ofFIGS. 20-25. In this embodiment, instead of the hypo tubes having a flared aspect, catheter hub incorporates flared areas or molded projections180extending from hub mounting collar. Thus upon advancement of catheter proximal end, the proximal end will widen adjacent catheter hub. This enables locking sleeve, e.g., the second series of threads154to engage the catheter at the extreme proximal end adjacent the hub mounting collar.

FIG. 27-29illustrate an alternate embodiment where locking sleeve200includes two interconnected components, namely, distal elastomeric component202and relatively rigid proximal component204. Rigid component204incorporates opposed locking tabs206and detents208receivable within locking grooves210of catheter hub in a similar manner to the embodiment ofFIG. 11. Elastomeric component202is adapted to form a seal about catheter member adjacent the extreme distal or leading end of the elastomeric component. The seal may incorporate a radially inwardly directed annular projection214or the like. The seal may minimize the passage of fluids through locking sleeve.

FIG. 29Aillustrates an alternate embodiment incorporating O-ring203. As locking sleeve200advances proximally over the first and second hypo tubes205,207, the locking sleeve200radially compresses the O-ring203between an internal shelf200S of the locking sleeve and the distal or leading face112aof catheter hub110. The compressed O-ring203secures catheter14to catheter hub110. O-ring203may be made of soft material, an elastomer, a rigid material, or any other suitable material. In an alternate embodiment depicted inFIG. 29B, internal shelf200S of locking sleeve200is adjacent the distal or leading end of the locking sleeve200.

FIG. 29Cdepicts an alternative embodiment of the locking sleeve200. In this embodiment, locking sleeve200includes a housing209extending distally therefrom. The housing209incorporates rigid detents211adapted to compress the catheter14against the hypo tubes205,207. Rigid detents211are biased inwardly with respect to the catheter14. The radial compression exerted by the rigid detents211secures the catheter14to the catheter hub. The housing209may include radial gaps to facilitate assembly and enhance grip. Additionally, the housing209may be clear to facilitate visualization of the position of the catheter14when the catheter14is advanced toward the catheter hub. As illustrated inFIGS. 29D and 29E, the housing209of locking sleeve200may further include an adhesive213therein. The adhesive213attaches the catheter14to the locking sleeve200and may compress the catheter14to form a fluid tight seal. After the proximal end of the catheter14is positioned within the housing209, the adhesive213seals and attaches catheter14to the catheter hub. At the same time, the rigid detents211of the housing209compress the catheter14against the hypo tubes205,207, thereby securing the catheter14to the catheter hub. Adhesive213may be any suitable kind of adhesive including, but not limited to, an adhesive hydrogel.

FIG. 30illustrates an alternate embodiment where locking sleeve220and hypo tubes222have a similar sloped, angled or arcuate surface224,226. This angled surface may enhance the interference relationship of the locking sleeve220with the catheter tube.

FIGS. 31-34illustrate another catheter hub170consisting of two half shells172connected to each other through a hinge174. The interior of the catheter hub170has arcuate recesses176which capture an outer ring178attached to the proximal end14pof the catheter14. In use, the proximal catheter end14pis positioned within the open catheter hub170with the ring178seated within one recess176of the half shell. The other half shell is folded onto the half shell and can be connected thereto via a snap fit or the like such as the pin and hole180,182arrangement shown. With the catheter ring178secured within the recess176of the catheter hub170the catheter is thereby secured to the hub170.

The use of any of the aforementioned catheter systems will now be discussed in connection with a subcutaneous tunneling procedure for hemodialysis. With reference toFIG. 35, the leading or distal end of the catheter may be implanted within a major vein of a patient via the reverse tunneling method disclosed in U.S. Pat. No. 5,509,897 to Twardowski, the entire contents of the '897 patent being incorporated herein by reference. In accordance with one embodiment of this procedure disclosed in the '897 patent, a catheter14is positioned through an incision “i” made beneath the clavicle, and advanced to enter the right atrium “ra”. A surgical tunnel is then created from the initial incision “i” outwardly to an exit site “e” remote from the original incision “i”. Alternatively, the surgical tunnel may be created from the exit site “e” to the initial incision “i.” A proximal section14pof the catheter14is advanced through the tunnel and out through the exit site “e”. With the proximal end of the catheter exposed, any of the aforementioned hub attachments mechanisms may be employed to attach the catheter hub to the catheter. Thereafter, the venous and arterial lines are connected to the catheter hub as is conventional.

Although the illustrative embodiments of the present disclosure have been described herein with reference to the accompanying drawings, it is to be understood that the disclosure is not limited to those precise embodiments, and that various other changes and modifications may be effected therein by one skilled in the art without departing from the scope or spirit of the disclosure.