US20040171997A1 - Double-y-shaped multi-lumen catheter with selectively attachable hubs - Google Patents

Abstract

A multi-lumen catheter and method for inserting same in a patient is disclosed. The catheter includes an elongated, central, multi-lumen tube portion having a proximal end and a distal end. The central tube portion has a substantially cylindrical outer shape and is internally segmented into a plurality of lumens. A distal branch portion includes a plurality of single-lumen distal extension tubes. Each distal extension tube has a proximal first end and a distal second end. The proximal first end of each distal extension tube is connected to the distal end of the central tube portion such that the single lumen of each distal extension tube is in fluid communication with one of the plurality of lumens of the central tube portion. A proximal branch portion includes a plurality of single-lumen proximal extension tubes. Each proximal extension tube has a distal first end and a proximal second end. The distal first end of each proximal extension tube is connected to the proximal end of the central tube portion such that the single lumen of each distal extension tube is in fluid communication with one of the plurality of lumens of the central tube portion. Each lumen of the central tube portion and the lumens of the distal and proximal extension tubes in fluid communication therewith define a flow path through the catheter. Selectively attachable hub connectors are provided for selective attachment to the distal extension tubes and connection of the catheter to a fluid exchange device.

Description

RELATED APPLICATIONS
• This application is a continuation-in-part of pending U.S. patent application Ser. No. 10/086,033, filed Feb. 28, 2002, which is a continuation of pending U.S. patent Application Ser. No. 09/769,052, filed Jan. 24, 2001.[0001]
BACKGROUND
• 1. Field of the Invention[0002]
• The present invention relates generally to medical instrumentation and more specifically to a multi-lumen catheter including y-shaped distal and proximal ends, and including selectively attachable hubs for selectively connecting the catheter to a fluid exchange device.[0003]
• 2. Description of the Prior Art[0004]
• Catheters, generally, are hollow, flexible tubes for insertion into a body cavity, duct, or vessel to allow the passage of fluids or distend a passageway. Catheters are often used for temporary or long-term dialysis treatment. Dialysis treatment provides for blood to be withdrawn from the patient, purified, and then returned to the patient. Thus, in dialysis treatment, catheters are used to allow passage of a patient's blood into and out of the patient's body. For optimal performance during dialysis treatment, the catheter tips, both in-flow and out-flow, should be placed in close proximity to the heart. Typically, medical personnel use either a double lumen catheter or two single lumen catheters. Both types, however, present certain deficiencies.[0005]
• While double lumen catheters (e.g., U.S. Pat. No. 4,895,561) allow for a single insertion of the catheter into the desired vein, double lumen catheters typically do not permit optimal catheter tip placement. Due to differences among patients, optimal tip position varies from patient to patient. Non-optimal tip position may significantly lower flow values, resulting in less effective dialysis treatment. For current double lumen catheters, a physician must make an estimate regarding the appropriate catheter tube length prior to beginning the procedure of catheterization. Then, a subcutaneous tunnel is made from a first end, which is near the area to be catheterized, to a second end, which is the preferred end position of the hub assembly, namely, away from the neck of the patient, in order to allow for more convenient access to the dialysis treatment equipment. The catheter tube is then routed forwardly into the through the subcutaneous tunnel from the second end to the first end so that the catheter tips extend outwardly from the first end of the tunnel. Either before or after tunneling, a sheath is inserted trough the first end of the tunnel and into the area to be catheterized, and the catheter tips are inserted into the sheath and the area to be catheterized. The estimated catheter tube length and subsequent forward tunneling may result in less than optimal tip placement.[0006]
• With the use of two independent single lumen catheters (e.g., U.S. Pat. No. 5,776,111 to Tesio) the problem of tip placement is addressed. The hub assembly of each catheter is removable from the tube and tip portion of the catheter, thereby allowing the catheter tip to be placed directly into the vein and advanced into the desired position. Then, the proximal end of the catheter can be reversed tunneled and trimmed to a desired length. Thereafter, the hub assembly is attached. Deficiencies, however, exist in this method of catheterization as well. One problem associated with this method is that this method requires two separate venous insertions, namely, two tunnels and two of each accessory instrument used for the procedure. Therefore, there is increased surgical time required to place two catheters, there are two wound entry sites which doubles the risk of post-surgical infection, and the two catheters together are significantly larger in diameter than one double lumen catheter.[0007]
• Applicant's co-pending application Ser. No. 09/769,052, filed Jan. 24, 2001, and Ser. No. 10/086,033, filed Feb. 28, 2002, disclose a multi-lumen catheter apparatus and method for inserting the apparatus in a patient. The disclosures of these co-pending applications are hereby incorporated by reference. In the disclosed apparatus and method, a multi-lumen catheter includes a selectively attachable hub assembly that allows the catheter tip to be positioned accurately within a patient's vein prior to subcutaneous tunneling. The distal end of the catheter tube is selectively attachable to the hub assembly. Accordingly, after the tips of the catheter have been accurately positioned in a patient, the other end of the catheter may be reverse tunneled under the skin of a patient. Before or after tip placement, an incision is made in the skin adjacent to the point where the protruding distal end of the catheter exits the skin. A subcutaneous tunnel is then formed having a first end at the incision and a second end exiting the skin at a point remote from the first end of the tunnel, generally as the caudal direction. A sheath dilator is inserted into the tunnel, which is partially dilated so as to accommodate a tissue in-growth stabilizing cuff. The distal end of the catheter tube is routed through the subcutaneous tunnel and the cuff seated therein, thereby stabilizing the distal portion of the catheter tube in the patient. A selectively attachable hub assembly is connected to the lumens at the distal tip of the catheter tube for subsequent connection of the catheter to a fluid exchange device, such as a dialysis machine.[0008]
• While the selectively attachable hub assembly described above facilitates tunneling a multi-lumen catheter in a patient, the separable hub assembly creates the need to connect the hub to a distal end of a multi-lumen catheter tube, thereby adding an additional step to the catheter insertion/connection procedure, which increases surgical time and expense. Furthermore, the hub-catheter connection provides an additional connection which may leak or separate from the catheter tube due to external loads on the hub such as by pulling or snagging. In addition, the attachable hub assembly is a relatively complex part, which makes it difficult to manufacture and, therefore, use of the hub assembly increases the cost of the catheter itself.[0009]
• Therefore, there is a need for a multi-lumen catheter that can be inserted into a patient using a reverse tunneling technique, which permits accurate placement of the tips of the catheter into the area to be catheterized and that is selectively attachable to a fluid exchange device. The improved catheter should not required an extensive hub assembly, thus making it relatively inexpensive to manufacture and easy to insert into a patient.[0010]
SUMMARY OF THE INVENTION
• A multi-lumen catheter is provided for use in hemodialysis and the like. The multi-lumen catheter includes an elongated, central, multi-lumen tube portion having a distal end and a proximal end. The central tube portion has a substantially cylindrical outer shape and is internally segmented into a plurality of lumens. A distal branch portion includes a plurality of single-lumen distal extension tubes. Each distal extension tube has a proximal first end and a distal second end. The proximal first end of each distal extension tube is connected to the distal end of the central tube portion such that the single lumen of each distal extension tube is in fluid communication with one of the plurality of lumens of the central tube portion. A proximal branch portion includes a plurality of single-lumen proximal extension tubes. Each proximal extension tube has a distal first end and a proximal second end. The distal first end of each proximal extension tube is connected to the proximal end of the central tube portion such that the single lumen of each distal extension tube is in fluid communication with one of the plurality of lumens of the central tube portion. A plurality of selectively attachable connector hubs are provided, each connector hub being configured to be selectively attachable to the distal second end of one of the distal extension and being configured for selective connection to a fluid exchange device. Each lumen of the central tube portion and the lumens of the distal and proximal extension tubes in fluid communication therewith define a flow path through the catheter. An in-growth stabilizing cuff may be affixed to an outer portion of the central tube portion.[0011]
• The multi-lumen catheter may include a central tube portion having two lumens. In such a catheter, the distal branch portion includes two distal extension tubes, and the proximal branch portion includes two proximal extension tubes. The catheter may be arranged such that the plurality of single-lumen distal extension tubes of the distal branch portion converge to form a distal multi-lumen connecting portion which connects to the distal end of the central tube portion, and the plurality of single-lumen proximal extension tubes comprising the proximal branch portion converge to form a proximal multi-lumen connecting portion which connects to the proximal end of the central tube portion.[0012]
• The central tube portion, the distal extension tubes, and the proximal extension tubes may be comprised of a fusible material, and the distal extension tubes and proximal extension tubes may be respectively fused to the distal and proximal ends of the central tube portion. The distal extension tubes may have a substantially cylindrical outer shape near their distal second ends, and the proximal multi-lumen connecting portion may also have substantially cylindrical outer shape. The proximal extension tubes may have a substantially D-shaped cross-section over at least a portion of their length. Also, the proximal extension tubes may be substantially parallel to each other in a free state, and the proximal second ends of the distal extension tubes may be longitudinally spaced from each other.[0013]
• The multi-lumen catheter may further include a plurality of connector hubs for connecting the catheter to a fluid exchange device. Each connector hub may configured to be connected to the distal second end of one of the distal extension tubes, and configured for connection to a portion of a fluid exchange apparatus. Each of the proximal extension tubes may include a tube wall, and each of the proximal extension tubes may include at least one opening extending through its tube wall. Further, an external portion of at least one of the distal extension tubes may include indicia which indicates a discrete flow path through the catheter. In one arrangement, the two proximal extension tubes have longitudinal axes which intersect at an included angle in a free state, the included angle being in a range from about 10 degrees to about 30 degrees.[0014]
• A y-shaped catheter junction for a multi-lumen catheter is also provided. The y-shaped junction includes a dual-lumen trunk, having a substantially cylindrical outer wall, a first end, a second end, a first lumen, and a second lumen. A first single-lumen extension tube is connected to the first end of the trunk, such that the single lumen of the first single-lumen extension tube is in fluid communication with the first lumen of the trunk. A second single-lumen extension tube is connected to the first end of the trunk such that the single lumen of the second single-lumen extension tube is in fluid communication with the second lumen of the trunk. The y-shaped junction is arranged such that the first lumen of the trunk and the first extension tube define a first flow path, and the second lumen of the trunk and the second extension tube define a second flow path. The y-shaped catheter junction may also be arranged such that the first and second extension tubes have longitudinal axes which intersect at an included angle near the first end of the trunk in a free state; the included angle being in a range from about 10 degrees to about 30 degrees.[0015]
• A method of forming a multi-lumen catheter is also disclosed. The method includes attaching a first plurality of single-lumen extension tubes to a distal end of a length of multi-lumen tubing comprising a plurality of multiple lumens, and attaching a second plurality of single-lumen extension tubes to a distal end of the length of multi-lumen tubing. Each single lumen of each extension tube is in fluid communication with one of the lumens of the length of multi-lumen tubing. The length of multi-lumen tubing may include two lumens, and the first and second pluralities of extension tubes may form substantially y-shaped junctions on each end of the length of multi-lumen tubing.[0016]
• The method of forming a multi-lumen catheter may include first forming a y-shaped distal junction. The process may include providing a first length of single-lumen tubing to form a distal arterial extension tube, providing a second length of single-lumen tubing to form a distal venal extension tube, providing a first length of multi-lumen tubing comprising at least an arterial lumen and a venal lumen, and having a distal end and a proximal end, attaching an end of the distal arterial extension tube to the distal end of the first length of multi-lumen tubing such that the distal arterial extension tube is in fluid communication with the arterial lumen of the first length of multi-lumen tubing, and attaching an end of the distal venal extension tube to the distal end of the first length of multi-lumen tubing such that the distal venal extension tube is in fluid communication with the venal lumen of the first length of multi-lumen tubing. The proximal end of the first length of multi-lumen tubing forms a connecting end.[0017]
• A second length of multi-lumen tubing having a distal end and a proximal end is provided. The tubing includes an arterial lumen and a venal lumen. The connecting end of the first length of multi-lumen tubing is connected to the distal end of the second length of multi-lumen tubing, such that the arterial extension tube of the distal junction is in fluid communication with the arterial lumen of the second length of multi-lumen tubing, and the venal extension tube of the distal junction is in fluid communication with the venal lumen of the second length of multi-lumen tubing.[0018]
• A y-shaped proximal junction is also formed. This process includes providing a third length of single-lumen tubing to form a proximal arterial extension tube, and providing a fourth length of single-lumen tubing to form a proximal venal extension tube. A third length of multi-lumen tubing is also provided which includes at least an arterial lumen and a venal lumen, and has a distal end and a proximal end. An end of the proximal arterial extension tube is attached to the distal end of the third length of multi-lumen tubing such that the proximal arterial extension tube is in fluid communication with the arterial lumen of the third length of multi-lumen tubing. Also, an end of the proximal venal extension tube is attached to the distal end of the third length of multi-lumen tubing such that the proximal venal extension tube is in fluid communication with the venal lumen of the third length of multi-lumen tubing. The distal end of the third length of multi-lumen tubing forms an attachment end.[0019]
• The attachment end of the third length of multi-lumen tubing is attached to the proximal end of the second length of multi-lumen tubing, such that the arterial extension tube of the proximal junction is in fluid communication with the arterial lumen of the second length of multi-lumen tubing, and the venal extension tube of the proximal junction is in fluid communication with the venal lumen of the second length of multi-lumen tubing. The method may also include forming at least one opening in a wall of the proximal venal extension tube, and forming at least one opening in a wall of the arterial proximal extension tube. The steps of attaching extension tubes and lengths of multi-lumen tubing together or to each other may include heat welding or similar fusing techniques. The longitudinal axes of the distal arterial extension tube and distal venal extension tube may be arranged to intersect at an included angle in a free state in a range from about 10 degrees to about 30 degrees.[0020]
• A method for surgically implanting a double-y shaped multi-lumen catheter into a patient is also provided. The method is suited for implanting a multi-lumen catheter having a an elongated, central, multi-lumen tube portion, a proximal end portion including a single-lumen proximal venal extension tube and a single-lumen proximal arterial extension tube each having a proximal tip, and a distal end portion including a single-lumen distal venal extension tube and a single-lumen distal arterial extension tube each having a distal end. The method includes making an incision in the skin of the patient, and inserting the proximal tips of the proximal venal and arterial extension tubes through the incision and placing the proximal tips in the patient. A subcutaneous tunnel is formed having a first end proximate to the incision and a second end remote from the first end of the tunnel. The distal venal and arterial extension tubes and at least a portion of the central tube portion are guided through the subcutaneous tunnel such that at least the distal ends of the distal venal and arterial extension tubes extend outwardly from the tunnel through the second end of the tunnel. At least a portion of the distal end portion of the catheter is secured to the patient such as by sutures or any other suitable means.[0021]
• When the catheter includes a stabilizing cuff, the method may further include dilating at least a portion of the subcutaneous tunnel to receive the cuff. Dilation of the tunnel may be accomplished by sliding a sheath dilator along the shaft of a trocar longitudinally positioned within the tunnel. The distal end portion of the catheter is secured to the patient by seating the cuff in a dilated portion of the subcutaneous tunnel.[0022]
• The catheter implanting method may further include respectively connecting the distal arterial and venal extension tubes to arterial and venal legs of a fluid exchange device. Connecting the distal arterial and venal extension tubes may include connecting the distal arterial extension tube to the arterial leg with a first connector hub, and connecting the proximal venal extension tubes to the venal leg with a second connector hub. Inserting the proximal tips of the proximal venal and arterial extension tubes into a patient may include placing the proximal tip of the venal extension tube into a vein in the patient, and placing the proximal tip of the arterial extension tube into an artery in the patient.[0023]
• These and other aspects of the invention will be made clear from a reading the following detailed description together with the drawings.[0024]
BRIEF DESCRIPTION OF THE DRAWINGS
• FIG. 1 is a perspective view of a double y-shaped multi-lumen catheter;[0025]
• FIG. 2 is a cross-sectional view of a distal portion of the multi-lumen catheter of FIG. 1;[0026]
• FIG. 3 is a partially exploded detail perspective view of a distal portion of the multi-lumen catheter of FIG. 1;[0027]
• FIG. 4 is a partially exploded detail perspective view of a proximal portion of the multi-lumen catheter of FIG. 1;[0028]
• FIG. 5 is a cross-sectional view of a proximal portion of the multi-lumen catheter of FIG. 1;[0029]
• FIGS. 6A-6D illustrate a procedure for tunneling a multi-lumen catheter like that of FIG. 1 in a patient;[0030]
• FIG. 7 is a partial sectional view of a sheath dilator engaged along a trocar to dilate a portion of a subcutaneous tunnel in a patient;[0031]
• FIGS. 8A-8C are views of a connection between a distal end of the catheter and a trocar for guiding the catheter through a subcutaneous tunnel.[0032]
DETAILED DESCRIPTION
• For the purposes of the following description and the claims appended hereto, the relative term “proximal” refers to those portions of a catheter and those portions of components of the catheter which are nearest the insertion end of the catheter, that is, the end of the catheter that is inserted into an area of a patient's body being catheterized, such as a blood vessel. Conversely, the relative term “distal” refers to those portions of a catheter and those portions of components of the catheter which are farthest from the insertion end of the catheter.[0033]
• FIG. 1 shows a double-Y shaped[0034]multi-lumen catheter10 according to the present invention. Thecatheter10 includes aproximal end34 for insertion into a patient, and adistal end36 for connection to a fluid exchange device, such as a dialysis machine or the like. Thecatheter10 includes an elongated, central,multi-lumen tube portion12, a plurality of proximal single-lumen extension tubes14,16, and a plurality of distal single-lumen extension tubes18,20. In the embodiment shown, thecentral tube portion12 includes anarterial lumen5 and avenal lumen6. In this arrangement, thecatheter10 includes a proximalvenal extension tube14 and a distalvenal extension tube18 in fluid communication with thevenal lumen6, and a proximalarterial extension tube16 and a distal arterial extension tube in fluid communication with thearterial lumen5. Thecatheter10 may include a stabilizingcuff15 affixed to an outer portion of thecentral tube portion12 as shown in FIG. 1. Preferably, thecuff15 is longitudinally positioned on thecentral tube portion12 such that thecuff15 will be finally positioned in a subcutaneous tunnel in a patient as described more fully below.
• A construction for the[0035]distal end36 of themulti-lumen catheter10 is shown in FIGS. 1-3. As shown in FIGS. 2 and 3, the proximal ends18p,20pof thedistal extension tubes18,20 may be connected to a distal end12dof thecentral tube portion12 by a distalmulti-lumen trunk30. The multiple lumens of thedistal trunk30 correspond in number to the multiple lumens of thecentral tube portion12 and the number ofdistal extension tubes18,20. In the illustrated embodiment, thedistal trunk30 includes a venaldistal trunk lumen48, and an arterialdistal trunk lumen47 as shown in FIG. 2. As shown in FIG. 3, the proximal ends18p,20pof thedistal extension tubes18,20 are connected to the distal end30dof the distal trunk, thereby forming a substantially Y-shaped junction. Theproximal end30pof thedistal trunk30 is connected to the distal end12dof thecentral tube portion12 as shown in FIG. 2, thereby forming a Y-shapeddistal end36. Preferably, theproximal end30pof thedistal trunk30 is substantially cylindrical in shape, and is substantially equal in outer diameter to the outer diameter of thecentral tube portion12, thereby providing a smooth transition at the juncture between thedistal trunk30 and thecentral tube portion12.
• As shown in FIG. 2, the distal extension tubes are arranged such that an included angle “θ” exists between the longitudinal axes of the[0036]tubes18,20 in a free state. In a preferred arrangement, the angle “θ” ranges from about 10 degrees to about 30 degrees. Thedistal extension tubes18,20 can be arranged, however, so that the angle “θ” is any desired angle. The venaldistal trunk lumen48 is in fluid communication with thevenal lumen6 of thecentral tube portion12 and the single lumen of the distalvenal extension tube18. Similarly, the arterialdistal trunk lumen47 is in fluid communication with thearterial lumen5 of the and the single lumen of the distalarterial extension tube20.
• In an alternative arrangement, the[0037]distal extension tubes18,20 may be connected directly to the distal end12dof thecentral tube portion12 rather than to an interconnected distal trunk30 (not shown). In either arrangement, the mating end portions of thedistal extension tubes18,20, the distal end of the central tube portion12d, and/or thedistal trunk30 are sealably fused together by heat welding or the like such that the fluid communication between the interconnecting lumens of the components is established and maintained and no leakage occurs at the connections.
• As shown in FIGS. 1-3, the[0038]catheter10 also includes selectivelyattachable connector hubs72,74 on the distal ends18d,20dof thedistal extension tubes18,20. As will be described in detail below, theconnector hubs72,74 are selectively attachable so that theconnector hubs72,74 can be attached to and removed from thedistal end36 of thecatheter10 after insertion of theproximal end34 of thecatheter10 into a patient, and after reverse, subcutaneous tunneling of thedistal end36. As shown in FIGS. 1 and 2, theconnector hubs72,74 are configured for selective sealable attachment between the distal ends18d,20dof thedistal extension tubes18,20 and legs of a fluid exchange device. The connector hubs. Thevenal connector hub74 is selectively attachable to the distal portion18dof the distalvenal extension tube18, and thearterial connector hub72 is selectively attachable to thedistal portion20dof the distalarterial extension tube20.
• In one embodient as shown in FIGS. 1-3, the selectively[0039]attachable hubs72,74 are connectable withmating compression fittings58,60. The compression fittings may includecannulae66,68 and threadedmale portions62,64 that matingly engage thedistal extension tubes18,20 and theconnector hubs72,74 as shown in FIG. 2. When fully engaged, thehubs72,74 andcompression fittings58,60compress compression sleeves70 about thedistal portions18d,20dof thedistal extension tubes18,20, thereby forming sealed connections. Thecompression fittings58,60 may be further connected to luer-type fittings50,52 or the like byconnector tubes54,56. The luer-type fittings50,52 may then be connected to corresponding luer-type connection mechanisms on afluid exchange device200. For example, the distal ends of the luer-type fittings50,52 may include quarter-turn type threads for leak-tight engagement with matching quarter-turn fittings on the venal and arterial legs of afluid exchange device200. Other types of known leak-tight selectively attachable connection configurations may also be used.
• As shown in FIGS. 1 and 3, the[0040]connector hubs72,74 can be selectively attached to the distal ends18d,20dof thedistal extension tubes18,20. This arrangement permits thedistal end36 of thecatheter10 to be subcutaneously reverse tunneled in a patient as described more fully below without interference from thehubs72,74. After the distal end of thecatheter10 is subcutaneously reverse tunneled in a patient such that thedistal end36 protrudes outwardly from the patient, thehubs72,74 can be backfit over the distal ends ofdistal extension tubes18,20 as shown forhub72 in FIG. 3. Thecompression sleeves70 can then be placed over the distal ends18d,20dof theextension tubes18,20, and the sealed connections can be completed as shown in FIG. 2. Thecatheter10 can then be connected to afluid exchange device200.
• A construction for the[0041]proximal end34 of thecatheter10 is shown in FIGS. 1, 4, and5. The distal ends14d,16dof theproximal extension tubes14,16 may be connected to aproximal end12pof thecentral tube portion12 by a proximalmulti-lumen trunk32. The lumens of theproximal trunk32 correspond in number to the multiple lumens of thecentral tube portion12 and to the number ofproximal extension tubes14,16. In the illustrated embodiment, theproximal trunk32 includes a venalproximal trunk lumen31, and an arterial proximal trunk lumen33 as shown in FIG. 5. As shown in FIG. 4, the distal ends14d,16dof theproximal extension tubes14,16 are connected to theproximal end32pof theproximal trunk32, thereby forming a substantially Y-shaped junction. Thedistal end32dof theproximal trunk32 is connected to theproximal end12pof thecentral tube portion12 as shown in FIG. 5, thereby forming a substantially Y-shapedproximal end34 on thecatheter10. Preferably, thedistal end32dof theproximal trunk32 is substantially cylindrical in shape, and is substantially equal in outer diameter to the outer diameter of thecentral tube portion12, thereby providing a smooth transition at the juncture between theproximal trunk32 and thecentral tube portion12.
• As shown in FIG. 4, the proximal extension tubes are arranged such that an included angle “α” exists between the longitudinal axes of the[0042]tubes14,16 in a free state. In a preferred arrangement, the angle “α” is about 5 degrees in a rest position or free state. Thedistal extension tubes18,20 can be arranged, however, so that the angle “α” is any desired angle. The venalproximal trunk lumen31 is in fluid communication with thevenal lumen6 of thecentral tube portion12 and the single lumen of the proximalvenal extension tube14. Similarly, the arterial proximal trunk lumen33 is in fluid communication with thearterial lumen5 of thecentral tube portion12 and the single lumen of the proximalarterial extension tube16.
• In an alternative arrangement, the[0043]proximal extension tubes14,16 may be connected directly to theproximal end12pof thecentral tube portion12 rather than to an interconnecting proximal trunk32 (not shown). In either arrangement, the mating end portions of theproximal extension tubes14,16, the proximal end of thecentral tube portion12p, and/or theproximal trunk32 are sealably fused together, such as by heat welding or the like, such that the fluid communication between the interconnected lumens of the components is established and maintained and no leakage occurs at the connections.
• As shown in FIGS. 1, 4, and[0044]5, the proximalarterial extension tube16 is preferably shorter in length than the proximalvenal extension tube14. For example, the proximalarterial extension tube16 may be about 4 cm shorter in length than the proximalvenal extension tube14. The resulting longitudinal spacing between theproximal tips14pand16pfacilitates optimal proximal tip placement in a patient. As shown in FIG. 4, the proximalvenal extension tube14 may include anend opening43 in or near itsproximal tip14p. The proximalvenal extension tube14 may also include one or moretransverse openings42 in itstube wall40. Similarly, as also shown in FIG. 4, the proximalarterial extension tube16 may include anend opening47 in or near itsproximal tip16p. The proximalarterial extension tube16 may also include one or moretransverse openings46 in itstube wall44. Theopenings42,43,46, and47 facilitate fluid flow into or out from theproximal extension tubes14,16.
• The[0045]hubs72 and74 are selectively attachable and detachable from thedistal end36 of thecatheter10 to facilitate tunneling thecatheter10 in a patient. A method of installing acatheter10 in a patient is illustrated in FIGS. 6A-6D. As shown in FIG. 6A, anincision100 is made in the skin of a patient. Theproximal tips14p,16pofcatheter10 are inserted through theincision100 and are placed at desired locations within the patient using conventional techniques, such as the Seldinger technique.
• At this stage, the[0046]distal end36 and distal portions of thecatheter10 extend outwardly from theincision100. Atrocar120 or other suitable instrument is used to form asubcutaneous tunnel102 having afirst end104, which is preferably coincident with theincision100, and an opposedsecond end106, which is remote from thefirst end104, as shown in FIG. 6A.
• As shown in FIG. 6B, the[0047]distal end36 of thecatheter10 is inserted through thefirst end104 of thetunnel102, and thedistal end36 is guided through thetunnel102 such that thedistal end36 extends out from thetunnel102 at itssecond end106. Thedistal extension tubes18,20 are sufficiently flexible that they may be bundled or clamped together by any suitable means to facilitate passing the Y-shapeddistal end36 of thecatheter10 through thetunnel102.
• In a preferred arrangement as shown in FIGS. 8A and 8B, the distal ends[0048]18d,20dof thedistal extension tubes18,20 are attached to aconnector300. The proximal end of theconnector300 may include afirst tip302 and asecond tip304 as shown. Thetips302,304 are insertable into the lumens at the distal ends18d,20dof thedistal extension tubes18,20. Thetips302,304 preferably includeribs301 or the like to tightly engage within the distal ends18d,20dof thedistal extension tubes18,20 such that theconnector300 is securely but removably attached to theextension tubes18,20. When thetips302,304 are respectively engaged in thedistal extension tubes18,20, theconnector300 holds thedistal extension tubes18,20 in close arrangement as shown so that thedistal extension tubes18,20 can be simultaneously subcutaneously tunneled in a patient as described below. The distal end of theconnector300dpreferably includes abore306 which is configured to attachably receive aninsertion tip308 of thetrocar120. Thebore306 may includethreads310 which can be engaged withmating threads312 on theinsertion tip308 of thetrocar120. Alternatively, thebore306 may include acollar portion314 which snaps into agroove309 on theinsertion tip308 of thetrocar120 as shown in FIG. 8C. In this way, thedistal end300dof theconnector300 can be engaged on theinsertion tip308 of thetrocar120 to route the attacheddistal extension tubes18,20 through thesubcutaneous tunnel102 with thetrocar120. Once thedistal end36 of thecatheter10 has been drawn through thetunnel102, theconnector300 can be disengaged from thedistal extension tubes18,20.
• In order to provide the distal portions of the[0049]catheter10 with a smooth and compact outer profile to facilitate passage of thedistal end36 of thecatheter10 through thetunnel102, asheath320 may be used as shown in FIG. 8B. Thesheath320 is placed over at least a portion of theconnector300 and thedistal extension tubes18,20. Preferably, thedistal end320dof thesheath320 is tapered as shown. Thesheath320 and the distal portions of thecatheter10 can be drawn together through thetunnel102 with thetrocar120. Thesheath320 is removed from thecatheter10 once the distal portions of thecatheter10 have been drawn through thetunnel102.
• As shown in FIG. 6C, the[0050]distal end36 of thecatheter10 is drawn from thesecond end104 of thetunnel102 such that thedistal extension tubes18,20 and at least a portion of thecentral tube portion12 extends from thesecond end104 and thecatheter10 is fully tunneled in the patient. Theincision100 and thesecond end104 of the tunnel are suitably treated and dressed.
• An outer portion of the[0051]central tube portion12 may include a tissue in-growth stabilizing cuff15, as shown in FIG. 1, for stabilizing the insertedcatheter10 in the patient. Referring to FIGS. 6C and 7, when thecatheter10 includes a stabilizingcuff15, aportion130 oftunnel102 may be dilated to enlarge the width of thetunnel102 to receive thecuff15 as thecatheter10 is drawn through thetunnel102. As shown in FIG. 7, the dilatedportion130 of the tunnel is preferably dilated by sliding asheath dilator200 over anend42 andshaft41 of thetrocar120 when thetrocar120 is positioned in thesubcutaneous tunnel102 as shown in FIG. 6A. Thesheath dilator200 preferably includes ahollow bore208, a taperedleading end206, a substantiallycylindrical portion204, and ahandle202. Thesheath dilator200 is inserted through thefirst end104 of thetunnel102 and into thetunnel102 until thetip206 has been inserted proximate to acuff seating point140 in thetunnel102 to form a dilatedportion130 of thetunnel102. Once the dilatedportion130 is sufficiently dilated, thesheath dilator200 is removed from thetunnel102 and thetrocar120. Thecatheter10 is finally positioned in thetunnel102 when thecuff15 is seated near anend140 of the dilatedportion130 of thetunnel102 as shown in FIG. 6C.
• As shown in FIG. 6D, the[0052]catheter10 is connected to afluid exchange device200. The distal end18dof the distalvenal extension tube18 is selectively attached to a venal leg224 of thefluid exchange device200 byconnector hub74. Similarly, thedistal end20dof the distalarterial extension tube20 is selectively attached to anarterial leg222 of thefluid exchange device200 byconnector hub72. As shown in FIG. 3,indicia26 and28 may be included on thedistal extension tubes18,20 and/or theconnector hubs72,74 to assist medical personnel in identifying the properdistal extension tube18 or20 for connection to a corresponding leg of thefluid exchange device300. Theindicia26,28 may be markings, colors, or any other distinctive indicator.
• While this invention has been illustrated and described in accordance with a preferred embodiment, it is recognized that variations and changes may be made therein without departing from the invention as set forth in the claims. Certain modifications and improvements will occur to those skilled in the art upon a reading of the forgoing description. For example, while the multi-lumen catheter has been described with reference to a catheter with two lumens, the invention also includes multi-lumen catheters including three or more lumens as required. It should be understood that all such modifications are not contained herein for the sake of conciseness and readability, but are properly within the scope of the following claims.[0053]

Claims (31)

What is claimed is:

1. A multi-lumen catheter comprising:

(a) a central, elongated, multi-lumen tube portion having a proximal end and a distal end, the central tube portion having a substantially cylindrical outer shape and being internally segmented into a plurality of lumens;

(b) a distal branch portion comprising a plurality of single-lumen distal extension tubes, each distal extension tube having a proximal first end and a distal second end, the proximal first end of each distal extension tube being permanently connected to the distal end of the central tube portion such that the single lumen of each distal extension tube is in fluid communication with one of the plurality of lumens of the central tube portion;

(c) a proximal branch portion comprising a plurality of single-lumen proximal extension tubes, each proximal extension tube having a distal first end and a proximal second end, the distal first end of each proximal extension tube being permanently connected to the proximal end of the central tube portion such that the single lumen of each distal extension tube is in fluid communication with one of the plurality of lumens of the central tube portion; and

(d) a plurality of selectively attachable connector hubs, each connector hub being configured to be selectively attachable to the distal second end of one of the distal extension and being configured for selective connection to a fluid exchange device;

wherein each lumen of the central tube portion and the lumens of the distal and proximal extension tubes in fluid communication therewith define a flow path through the catheter.

2. A multi-lumen catheter according toclaim 1, wherein the central tube portion includes two lumens, the distal branch portion includes two distal extension tubes, and the proximal branch portion includes two proximal extension tubes.

3. A multi-lumen catheter according toclaim 1 wherein the plurality of single-lumen distal extension tubes of the distal branch portion converge to form a distal multi-lumen connecting portion which connects to the distal end of the central tube portion, and the plurality of single-lumen proximal extension tubes comprising the proximal branch portion converge to form a proximal multi-lumen connecting portion which connects to the proximal end of the central tube portion.

4. A multi-lumen catheter according toclaim 1 wherein the central tube portion, the distal extension tubes, and the proximal extension tubes are comprised of a fusible material, and the distal extension tubes and proximal extension tubes are respectively fused to the distal and proximal ends of the central tube portion.

5. A multi-lumen catheter according toclaim 1 wherein the distal extension tubes have a substantially cylindrical outer shape near their distal second ends.

6. A multi-lumen catheter according toclaim 3 wherein the proximal extension tubes have a substantially D-shaped cross-section over at least a portion of their length.

7. A multi-lumen catheter according toclaim 3 wherein the proximal multi-lumen connecting portion has a substantially cylindrical outer shape.

8. A multi-lumen catheter according toclaim 1 wherein the proximal extension tubes are substantially parallel to each other in a free state.

9. A multi-lumen catheter according toclaim 1 wherein the at least one of the proximal extension tubes is shorter in length than at least one other proximal extension tube.

10. A multi-lumen catheter according toclaim 1 further including a stabilizing cuff affixed to an outer portion of the central tube portion.

11. A multi-lumen catheter according toclaim 1 wherein the proximal end of each selectively attachable connector hub includes a tube portion configured to be sealably inserted into a portion of a lumen at the distal second end of one of the distal extension tubes.

12. A multi-lumen catheter according toclaim 11 wherein the tube portion of each connector hub includes at least one outer circumferential step, barb, or ridge for releasably gripping a portion of a distal extension tube into which the tube portion is inserted.

13. A multi-lumen catheter according toclaim 1, wherein each of the proximal extension tubes includes a tube wall, and each of the proximal extension tubes includes at least one opening extending through its tube wall.

14. A multi-lumen catheter according toclaim 1, wherein an external portion of at least one of the distal extension tubes includes indicia, the indicia indicating a discrete flow path through the catheter.

15. A multi-lumen catheter according toclaim 2 wherein the two proximal extension tubes have longitudinal axes which intersect at an included angle in a free state, the included angle being in a range from about 10 degrees to about 30 degrees.

16. A y-shaped catheter junction comprising:

(a) a dual-lumen trunk having a substantially cylindrical outer wall, a first end, a second end, a first lumen, and a second lumen;

(b) a first single-lumen extension tube connected to the first end of the trunk, wherein the single lumen of the first single-lumen extension tube is in fluid communication with the first lumen of the trunk; and

(c) a second single-lumen extension tube connected to the first end of the trunk, wherein the single lumen of the second single-lumen extension tube is in fluid communication with the second lumen of the trunk;

wherein the first lumen of the trunk and the first extension tube define a first flow path, and the second lumen of the trunk and the second extension tube define a second flow path.

17. A y-shaped catheter junction according toclaim 16 wherein the first and second extension tubes have longitudinal axes which intersect at an included angle near a first end of the trunk in a free state, the included angle being in a range from about 10 degrees to about 30 degrees.

18. A method of forming a multi-lumen catheter, the method comprising permanently attaching a first plurality of single-lumen extension tubes to a distal end of a length of multi-lumen tubing comprising a plurality of multiple lumens, and permanently attaching a second plurality of single-lumen extension tubes to a distal end of the length of multi-lumen tubing, wherein each single lumen of each extension tube is in fluid communication with one of the lumens of the length of multi-lumen tubing.

19. A method according toclaim 18, wherein the length of multi-lumen tubing includes two lumens, and the first and second pluralities of extension tubes form substantially y-shaped junctions on each end of the length of multi-lumen tubing.

20. A method of forming a multi-lumen catheter according toclaim 19, the method comprising:

(a) forming a y-shaped distal junction including:

(i) providing a first length of single-lumen tubing to form a distal arterial extension tube;

(ii) providing a second length of single-lumen tubing to form a distal venal extension tube;

(iii) providing a first length of multi-lumen tubing comprising at least an arterial lumen and a venal lumen, and having a distal end and a proximal end;

(iv) permanently attaching an end of the distal arterial extension tube to the distal end of the first length of multi-lumen tubing such that the distal arterial extension tube is in fluid communication with the arterial lumen of the first length of multi-lumen tubing; and

(v) permanently attacking an end of the distal venal extension tube to the distal end of the first length of multi-lumen tubing such that the distal venal extension tube is in fluid communication with the venal lumen of the first length of multi-lumen tubing;

wherein the proximal end of the first length of multi-lumen tubing forms a connecting end;

(b) providing a second length of multi-lumen tubing having a distal end and a proximal end, and having an arterial lumen and a venal lumen, and permanently attaching the connecting end to the distal end of the second length of multi-lumen tubing, such that the arterial extension tube of the distal junction is in fluid communication with the arterial lumen of the second length of multi-lumen tubing, and the venal extension tube of the distal junction is in fluid communication with the venal lumen of the second length of multi-lumen tubing;

(c) forming a y-shaped proximal junction including:

(i) providing a third length of single-lumen tubing to form a proximal arterial extension tube;

(ii) providing a fourth length of single-lumen tubing to form a proximal venal extension tube;

(iii) providing a third length of multi-lumen tubing comprising at least an arterial lumen and a venal lumen, and having a distal end and a proximal end;

(iv) permanently attaching an end of the proximal arterial extension tube to the distal end of the third length of multi-lumen tubing such that the proximal arterial extension tube is in fluid communication with the arterial lumen of the third length of multi-lumen tubing; and

(v) permanently attaching an end of the proximal venal extension tube to the distal end of the third length of multi-lumen tubing such that the proximal venal extension tube is in fluid communication with the venal lumen of the third length of multi-lumen tubing;

wherein the distal end of the third length of multi-lumen tubing forms an attachment end; and

(d) permanently attaching the attachment end to the proximal end of the second length of multi-lumen tubing, such that the arterial extension tube of the proximal junction is in fluid communication with the arterial lumen of the second length of multi-lumen tubing, and the venal extension tube of the proximal junction is in fluid communication with the venal lumen of the second length of multi-lumen tubing;

21. A method according toclaim 20, the method further comprising forming at least one opening in a wall of the proximal venal extension tube, and forming at least one opening in a wall of the arterial proximal extension tube.

22. A method according toclaim 20 wherein permanently attaching extension tubes and lengths of multi-lumen tubing together or to each other comprises fusing ends of the tubes or tubing together.

23. The method ofclaim 19, wherein the longitudinal axes of the distal arterial extension tube and the distal venal extension tube intersect at an included angle in a free state, the included angle being in a range from about 10 degrees to about 30 degrees.

24. A method for surgically implanting a double-y shaped multi-lumen catheter tube into a patient, the multi-lumen catheter including an elongated, central, multi-lumen tube portion, a proximal end portion including a single-lumen proximal venal extension tube and a single-lumen proximal arterial extension tube each having a proximal tip, and a distal end portion including a single-lumen distal venal extension tube and a single-lumen distal arterial extension tube each having a distal end, the method comprising:

(a) making an incision in the skin of the patient

(b) inserting the proximal tips of the proximal venal and arterial extension tubes through the incision and placing the proximal tips in the patient;

(c) forming a subcutaneous tunnel having a first end proximate to the incision and a second end remote from the first end of the tunnel;

(d) guiding the distal venal and arterial extension tubes and at least a portion of the central tube portion through the subcutaneous tunnel such that at least the distal ends of the distal venal and arterial extension tubes extend outwardly from the tunnel through the second end of the tunnel; and

(e) securing at least a portion of the distal end portion of the catheter to the patient.

25. A method according toclaim 24, the method further comprising respectively connecting the distal arterial and venal extension tubes to arterial and venal legs of a fluid exchange device.

26. A method according toclaim 25, wherein connecting the distal arterial and venal extension tubes to arterial and venal legs of a fluid exchange device comprises connecting the distal arterial extension tube to the arterial leg with a first connector hub, and connecting the proximal venal extension tubes to the venal leg with a second connector hub.

26. The method ofclaim 23, wherein inserting the proximal tips of the proximal venal and arterial extension tubes into a patient comprises:

placing the proximal tip of the venal extension tube into a vein in the patient; and

placing the proximal tip of the arterial extension tube into an artery in the patient.

28. The method ofclaim 24 wherein the central tube portion further includes a stabilizing cuff affixed to an outer portion of the central tube portion, the method further comprising dilating at least a portion of the subcutaneous tunnel before guiding the distal venal and arterial extension tubes and at least a portion of the central tube portion through the subcutaneous tunnel, wherein the dilating step comprises sliding a sheath dilator along a shaft of a trocar longitudinally positioned in the tunnel.

29. The method ofclaim 28 wherein securing at least a portion of the distal end portion of the catheter to the patient comprises seating the stabilizing cuff in a dilated portion of the subcutaneous tunnel.

30. The method ofclaim 24 wherein guiding the distal venal and arterial extension tubes and at least a portion of the central tube portion through the subcutaneous tunnel comprises:

(a) inserting a trocar through the subcutaneous tunnel such that an insertion tip of the trocar protrudes from the first end of the tunnel;

(b) connecting the distal ends of the distal venal and arterial extension tubes to a proximal end of a connector;

(c) connecting a proximal end of the connector to the protruding insertion tip of the trocar; and

(d) guiding the distal venal and arterial extension tubes and at least a portion of the central tube portion through the subcutaneous tunnel with the trocar.

31. The method ofclaim 30 further comprising placing a sheath having a smooth outer contour over the connector and at least portions of the venal and arterial extension tubes before guiding the distal venal and arterial extension tubes and at least a portion of the central tube portion through the subcutaneous tunnel with the trocar.

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