Patent Application
20100145285
1. Technical Field
The present application relates generally to a medical device, such as a catheter, for use in transporting fluids. More particularly, the application relates to a multi-lumen catheter for transporting a fluid from the body of a patient for extracorporeal treatment, and returning the treated fluid to the patient's body.
2. Background Information
Dual lumen catheters are commonly used for transporting a bodily fluid for treatment external of the patient's body, a process generally referred to in the medical field as “extracorporeal” treatment, and thereafter returning the treated fluid to the body. The fluid is withdrawn from the body through one of the lumens of the catheter, generally referred to as the withdrawal lumen. The fluid is subjected to a treatment process, and thereafter returned (or “infused”) to the body through the other lumen, generally referred to as the infusion lumen.
In many cases, the extracorporeal treatment is carried out as part of a hemodialysis procedure. During hemodialysis, blood is withdrawn from a blood vessel through the withdrawal lumen and routed to a dialyzer for cleansing. The cleansed blood is then returned to the blood vessel through the infusion lumen. When such a catheter is used for hemodialysis, it is generally inserted into the body through the interior jugular vein, the subclavian vein, or the femoral vein. In addition to hemodialysis, extracorporeal catheters can also be used for other procedures in which a fluid is removed from the body for treatment and later returned to the body.
A variety of hemodialysis catheters are available. Among the types of commercially available catheters are: 1) a dual lumen catheter having one lumen (e.g., the blood infusion lumen), that terminates distal to the other lumen (e.g., the blood withdrawal lumen). Some catheters of this type are provided with a midline split between the withdrawal and infusion lumens, while others do not have such a split (e.g., the COOK® DDS catheter); 2) a catheter having a slifted valve in the distal tip that acts as a pressure valve opening. This valve opens inwardly for blood aspiration, outwardly for blood infusion, and remains closed when not in use (e.g., the Groshong catheter); 3) polyester-cuffed central venous silicone catheters that are tunneled underneath the skin to reduce infection (e.g., Broviac, Leonard and Hickman catheters); 4) a dual lumen catheter having a tapered tip and two adjacent holes communicating with one lumen just proximal to the tip to assist with outflow, and two adjacent holes communicating with the other lumen (180 degrees removed) just proximal to the first set of holes to assist with inflow (e.g., the Mahurkar catheter); and 5) a dual lumen catheter having a diverting structure consisting of a shoulder that has a straight up distal face and a sloped proximal face to reduce access recirculation and raise pressure in the vicinity of the inlet aperture (U.S. Pat. No. 6,409,700).
Typically, dual lumen hemodialysis catheters have fixtures and related structure at the proximal end that are larger than the diameter of an introducer device through which the catheter is inserted into the vessel. As a result, splittable introducer sheaths, such as the PEEL-AWAY® introducers commercially available from Cook, Incorporated, of Bloomington, Ind., are often utilized for insertion of the catheter. Although such introducers are generally effective for such use, it would be desirable if the catheter insertion procedure could be simplified in a manner such that a separate introducer sheath would not be required. Eliminating the introducer device simplifies the procedure by omitting the sheath removal step that must otherwise be carried out by the physician, and also reduces the overall cost of the procedure. However, since many conventional hemodialysis catheters have stepped or otherwise non-tapered distal (e.g., entry) portions, these catheters are generally not amenable to non-traumatic insertion in the vessel without the use of a tapered introducer and/or dilator.
It would be desirable to provide a multi-lumen catheter for use in the extracorporeal transport of bodily fluids that is capable of insertion into a vessel in substantially non-traumatic fashion, and without the necessity of utilizing a separate introducer apparatus.
The present invention addresses the shortcomings of the prior art. In one form thereof, the invention comprises a multi-lumen catheter for use in the extracorporeal treatment of bodily fluids. The catheter comprises a tubular catheter body, wherein a first septum extends along a length of the catheter body. The catheter body has a withdrawal port and an infusion port. First and second withdrawal lumens are disposed on one side of the septum for transport of fluids withdrawn from a body vessel through the withdrawal port to an extracorporeal treatment unit. An infusion lumen is disposed on another side of the septum for infusion of treated fluids from the extracorporeal treatment unit through the infusion port into the vessel. The catheter body has a second septum extending along a length of the first septum. A proximal portion of the second septum separates the first and second withdrawal lumens. A distal portion of the second septum extends distal to the withdrawal port, and tapers to a termination point along the first septum length.
In another form thereof, the present invention comprises a catheter for use in the extracorporeal treatment of bodily fluids. The catheter comprises a generally cylindrical catheter body having a proximal end and a distal end, wherein the distal end tapers to a distal tip portion. The generally cylindrical catheter body has a first septum extending along the length of the catheter body, and has a withdrawal port and an infusion port axially spaced along the catheter body length. The catheter body has first and second withdrawal lumens disposed on one side of the septum for transport of the body fluid withdrawn from a body vessel through the withdrawal port to an extracorporeal treatment unit, and an infusion lumen disposed on another side of the septum for infusion of treated fluid from the extracorporeal treatment unit through the infusion port into the vessel. The catheter body has a second septum extending along a length of the first septum. A proximal portion of the second septum separates the first and second withdrawal lumens, and a distal portion of the second septum extends distal to the withdrawal port and tapers to a termination point along the first septum length.
In yet another form thereof, the invention comprises a method for treating a body fluid. A catheter is provided for transporting the body fluid. The catheter comprises a generally cylindrical catheter body having a proximal end and a distal end, wherein the distal end tapers to a distal tip portion. The catheter body has a first septum extending along its length, and has a withdrawal port and an infusion port. The catheter body has first and second withdrawal lumens disposed on one side of the first septum for transporting body fluid withdrawn from a body vessel through the withdrawal port to an extracorporeal treatment unit, and an infusion lumen disposed on another side of the septum for infusion of treated fluid from the extracorporeal treatment unit through the infusion port into the vessel. The catheter body has a second septum extending along a length of the first septum. A proximal portion of the second septum separates the first and second withdrawal lumens, and a distal portion of the second septum extends distal to the withdrawal port and tapers to a termination point along the first septum length. The distal end of the catheter body is inserted into the vessel, and the body fluid to be treated is withdrawn from the vessel through the withdrawal port. The withdrawn fluid is transported through the withdrawal lumens to a treatment instrument. Following treatment in the treatment instrument, the fluid is transported from the treatment instrument through the infusion lumen, and infused into the body vessel through the infusion port.
For purposes of promoting an understanding of the present invention, reference will now be made to the embodiments illustrated in the drawings, and specific language will be used to describe the same. It is nevertheless to be understood that no limitation of the scope of the invention is thereby intended, the scope of the invention being indicated by the claims appended below and the equivalents thereof. The figures are not all drawn to the same scale to avoid obscuring the details of the finer structures. The following detailed description of the preferred embodiments will make clear the preferred arrangement, size relationships and manner of using the components shown herein.
The present invention is directed to a multi-lumen catheter for use in the transport of bodily fluids for treatment external of the body, referred to in the medical arts as “extracorporeal” treatment. The bodily fluids are transported from the body through one or more withdrawal lumens in the catheter, and are thereafter transported to an instrument for extracorporeal treatment. The treated fluids are then returned, or infused, to the body through an infusion lumen in the catheter.
In the following discussion, the terms “proximal” and “distal” will be used to describe the axial ends of the catheter, as well as the axial ends of various component features. The “proximal” end is used in conventional manner to refer to the end of the catheter (or component) that is closest to the operator during use of the assembly. The “distal” end is used in conventional manner to refer to the end of the catheter (or component) that is initially inserted into the patient, or that is closest to the patient.
Those skilled in the art will appreciate that the catheter described herein is suitable for multiple uses involving inflow and outflow of bodily fluids. However, the invention will be primarily described hereinafter with reference to one of its intended uses, namely as a hemodialysis catheter for use in the extracorporeal treatment of blood. The hemodialysis catheter enables blood inflow without disturbance, and blood return without hemolysis. In addition to hemodialysis, the catheter can be used for other extracorporeal fluid treatments in which a body fluid is withdrawn from the body, subjected to a treatment process, and thereafter returned to the body. Pheresis and hemofiltration are non-limiting examples of such additional procedures.
Catheter assembly 100 includes a conventional bifurcated fitting, such as manifold 110, positioned at the proximal end of catheter body 102. Conventional suture wings 112 may be provided if desired. Stop mechanisms 114, 116 may be provided at each axial side of suture wings 112 to prevent catheter body 102 from axial movement relative to the suture wings. Flexible extension tubes 120, 122 extend in the proximal direction from manifold 110. Each extension tube is in fluid communication with a separate one of lumens 104, 106. Clamps 126, 128 are provided for selectively closing off fluid flow through the respective extension tubes 120, 122. Luer lock or other suitable connecting mechanisms 130, 132 are provided for engagement with a treatment instrument 140, such as a dialyzer, for establishing a flow path of blood to and from the dialyzer. Dialyzer 140 and its ingress and egress openings are shown schematically in
In the prior art hemodialysis catheter assembly 100 shown in
Another prior art hemodialysis catheter assembly 200 is shown in
Prior art assembly 200 includes an elongated generally cylindrical catheter body 202, and has dual lumens 204, 206 extending therethrough. Lumen 204 is separated from lumen 206 by septum 208. Withdrawal port 212 communicates with lumen 206 for transporting fluid withdrawn from the vessel through the catheter assembly to the dialyzer. Treated fluid returns to the vessel through lumen 204 and infusion port 214, in the same manner described with reference to the prior art embodiment of
Unlike the generally perpendicular orientation of the withdrawal port 144 of prior art assembly 100, the withdrawal port 212 of prior art assembly 200 comprises a straight angled cut. This design allows for easier insertion into the vessel when compared to assembly 100. However, the straight angled arrangement defined by angle a (
The multi-lumen catheter of the present invention may be readily understood by viewing an embodiment of the invention depicted in
Multi-lumen catheter 10 includes an elongated tubular catheter body 12. Preferably, catheter body 12 has a generally cylindrical construction, and tapers to a distal tip portion 19. As best illustrated in the sectional view of
In the preferred embodiment of
In use, the proximal end of catheter body 12 is preferably received in a conventional bifurcated fitting, such as manifold 110 shown in
As illustrated in
Catheter body 12 preferably includes a distal end portion 19 that tapers to infusion port 20 as shown in
Preferably, the total combined cross-sectional areas of infusion port 20 and side port(s) 21 is at least as great as the cross-sectional area of the infusion lumen. As a result, the infusion flow rate will not be reduced due to the reduction in diameter at the tapered distal tip, and fluid will not be backed-up in the infusion lumen. Preferably, side port 21 is spaced about 1 mm proximal to a transition point 22, designated as the point where the main catheter body portion 12 meets the tapered tip 19. Although a single side port 21 is illustrated in the embodiment shown herein, those skilled in the art will appreciate that additional side ports can be provided in the catheter body if desired. In order to minimize the possibility of re-mixing treated fluid passing through the side port(s) with untreated fluid entering the withdrawal port 18, it is preferred to maintain the side port(s) as close to the distal end of the catheter as practicable.
As stated, vertical septum 28 preferably extends to the proximal end of catheter body 12. If desired, however, the vertical septum 28 may terminate at any position within the catheter body prior to the proximal end. In this event, lumens 14, 15 would merge into a single withdrawal lumen from the point of termination of the septum to the proximal end of the catheter body. However, for ease of manufacturing, and to maintain optimal stiffness of catheter 10 at its proximal portion, it is generally preferred to extend vertical septum 28 to the proximal end of catheter body 12.
As best illustrated in
Those skilled in the art will appreciate that the length and degree of inclination of the tapered septum 28 is generally not critical, as long as the septum has sufficient length and taper to provide the benefits described. However, in most instances, a longer taper is beneficial as it will provide less resistance during percutaneous insertion than a shorter taper. Similarly, the degree of taper of catheter body distal end 19 is generally not critical, as long as the angle of taper is sufficient to avoid undue trauma upon insertion of the catheter end into the vessel.
Another feature that may be varied to assist catheter insertion is the angle of the withdrawal port 18 relative to the horizontal septum 30. As illustrated in prior art
Thus, as described above, various features of the inventive catheter 10 may be modified as desired to facilitate insertion of the inventive catheter into a vessel in a manner that minimizes trauma to the patient. Those skilled in the art are believed capable of optimizing the variables described herein for a particular purpose, without requiring undue experimentation.
An alternative embodiment of a multi-lumen catheter 50 according to the invention is shown in
Once again, a horizontal septum 70 spans the length of catheter body 52, and bisects the upper and lower portions of catheter body 52. Vertical septum 68 bisects portions of the upper catheter body. Horizontal septum 70 defines a surface that separates withdrawal lumens 54, 55 from infusion lumen 56, and vertical septum 68 defines a surface that separates the two withdrawal lumens 54, 55. Withdrawal port 58 communicates with withdrawal lumens 54, 55 for transporting fluid withdrawn from the vessel to the dialyzer, and infusion port 60 and one or more side ports 61 communicate with infusion lumen 56 for transporting treated fluid back to the vessel.
The proximal portions of catheter 50 may be the same as the proximal portions of catheter 10. The distal portion of vertical septum 68 tapers in the distal direction from withdrawal port 58 to a distal termination point 69 along the distal length of horizontal septum 70 in the same manner as in the previous embodiment.
Unlike catheter 10, the withdrawal port 58 of catheter 50 is perpendicular to the horizontal septum 70, in the manner of prior art sheath 100. With this configuration, it is less likely that the withdrawal port will be occluded by the vessel wall, when compared to an angled withdrawal port. However, as stated, this configuration may be more likely to impede smooth insertion of the catheter into the vessel in some instances when compared to the angled withdrawal port 18.
Catheter body 12, 52 may be formed from a conventional polymer commonly used in the medical arts for such purposes, such as radiopaque polyurethane. Other conventional materials used for such purposes in the medical arts may be substituted. Non-limiting examples of such materials include silicone, polyurethane and PTFE.
Typically, catheter body 12, 52 will be formed by a conventional extrusion process. The exposed portions of vertical septum 28, 68 (i.e., the portions of the vertical septum distal to withdrawal ports 18, 58), can be formed by cutting away unnecessary distal portions of the extruded catheter body. Alternatively, the exposed portions of the vertical septum can be formed by a secondary molding process. This process would involve cutting away the upper portion of the extruded catheter body 12, 52 distal of withdrawal port 18, 58, and molding the exposed portions of vertical septum 28, 68 onto horizontal septum 30, 70 distal of the withdrawal port as shown. The one or more side ports may be formed in conventional fashion, such as by punching or skiving the ports through catheter body 12, 52.
Insertion of the catheter into the vessel can be made over a wire guide, e.g., via the well-known Seldinger percutaneous entry technique. Transport of bodily fluid to the dialyzer and return of the treated fluid to the body vessel follows a path substantially similar to that of the prior art embodiments previously described, and need not be further discussed for an understanding of the present invention.
It is therefore intended that the foregoing detailed description be regarded as illustrative rather than limiting, and that it be understood that it is the following claims, including all equivalents, that are intended to define the spirit and scope of this invention.
