Abstract:
The bifurcated peritoneal catheter serves as a peritoneal dialysis device for patients with kidney failure. The catheter includes a primary tube with two porous internal tubes extending therefrom at a small acute angle to one another. The two internal tubes provide a solution to the potential problem of blockage in a single catheter tube, greatly reducing the potential need for surgery to remove and replace such a single catheter tube. The bifurcated peritoneal catheter includes a subcutaneous cuff, and can include a second deep cuff in the abdominal wall. Either or both of the internal tubes can be straight, curved or coiled, with the curvatures and coils oriented in the same direction, toward one another, or away from one another.

Description:
BACKGROUND OF THE INVENTION 
     1. Field of the Invention 
     The present invention relates generally to medical and surgical appliances and devices, and particularly to a series of embodiments of a bifurcated peritoneal catheter. 
     2. Description of the Related Art 
     Kidney failure, and particularly end stage renal failure, is an ultimately fatal disease that affects millions of people. The result is a buildup of impurities within the peritoneal cavity of the body. These impurities cannot be eliminated by the body, at least not to the degree necessary to maintain health. The only known cures at present are (1) peritoneal dialysis to purge waste materials from the body, or (2) kidney transplant from a suitable donor, which procedure is beyond the scope of the present invention. 
     In the case of peritoneal dialysis, a single tubular catheter (generally known as a Tenckhoff catheter, after its developer) is surgically installed within the peritoneal cavity of the patient. The catheter is used to periodically infuse a dialysate fluid into the peritoneal cavity, with the dialysate becoming contaminated with the collected impurities within the peritoneal cavity. The contaminated dialysate is then drawn from the patient&#39;s body. This procedure is normally performed a few times per day to maintain the health of the patient. 
     There are a number of potential problems that can occur with peritoneal catheters. For example, the single tube of the catheter can become displaced from the pelvic area, or perhaps become blocked due to fibrin buildup, or the open distal end can come in contact with some internal organ (bowel, etc.) to reduce fluid flow through the catheter. These problems have a frequency of occurrence approaching twenty percent. The only recourse is the surgical removal of the peritoneal catheter, repositioning of the catheter, or reinstallation of a new catheter. 
     Thus, a bifurcated peritoneal catheter solving the aforementioned problems is desired. 
     SUMMARY OF THE INVENTION 
     The bifurcated peritoneal catheter comprises a single primary tube having the majority of its length disposed externally to the body. A subcutaneous cuff seals the tube at its entrance into the body. A deeper second cuff at the abdominal wall can also be provided. Two internal catheter tubes connect to the distal end of the primary tube at a small acute angle, to provide minimal turbulence to internal fluid flow at the juncture of the internal tubes with the distal end of the primary tube. Fluid flow through the tubes is always in the same direction, i.e., the two internal tubes (as well as the primary tube, of course) simultaneously provide inflow of dialysate or outflow of contaminated fluid. The two internal tubes provide alternative flow paths in the event that one of the internal tubes becomes blocked, thereby greatly reducing the need for a subsequent operation to remove the catheter assembly and reinstall another. 
     A number of different embodiments are disclosed herein. The primary tube can have a single or double cuff, as noted further above. The distal end of the primary tube, i.e., that portion within the body, can be straight or can have a curve, known as a “swan neck,” particularly between the two cuffs when two such cuffs are provided. The two internal tubes can be straight, or either or both can be curved. Either or both of the internal tubes can be coiled, with the coil(s) oriented toward or away from the other internal tube. The tubes are devoid of internal structure and remain in their natural straight, curved, or coiled configurations after surgical implantation. 
     These and other features of the present invention will become readily apparent upon further review of the following specification and drawings. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG. 1  is a top plan view of a first embodiment of a bifurcated peritoneal catheter according to the present invention, wherein a single subcutaneous cuff is disposed along the entry tube and one leg of the catheter is straight. 
         FIG. 2  is a top plan view of a second embodiment of the bifurcated peritoneal catheter according to the present invention, wherein a single subcutaneous cuff is disposed along the entry tube and both catheter legs are slightly curved. 
         FIG. 3  is a top plan view of a third embodiment of the bifurcated peritoneal catheter according to the present invention, wherein subcutaneous and abdominal muscle wall cuffs are provided along the entry tube of the bifurcated peritoneal catheter embodiment of  FIG. 1 . 
         FIG. 4  is a top plan view of a fourth embodiment of the bifurcated peritoneal catheter according to the present invention, wherein subcutaneous and abdominal muscle wall cuffs are provided along the entry tube of the bifurcated peritoneal catheter embodiment of  FIG. 2 . 
         FIG. 5  is a top plan view of a fifth embodiment of the bifurcated peritoneal catheter according to the present invention, wherein the entry tube includes an acute bend between the two cuffs and the two peritoneal tubes are coiled away from one another. 
         FIG. 6  is a top plan view of a sixth embodiment of the bifurcated peritoneal catheter according to the present invention, wherein the entry tube includes an acute bend between the two cuffs and one of the two peritoneal tubes is coiled toward the other. 
         FIG. 7  is a top plan view of a seventh embodiment of the bifurcated peritoneal catheter according to the present invention, wherein the entry tube includes an acute bend between the two cuffs and one of the two peritoneal tubes is coiled away from the other. 
         FIG. 8  is a top plan view of an eighth embodiment of the bifurcated peritoneal catheter according to the present invention, wherein the entry tube includes an acute bend between the two cuffs and the two peritoneal tubes are coiled toward the entry tube. 
         FIG. 9  is a top plan view of a ninth embodiment of the bifurcated peritoneal catheter according to the present invention, wherein the entry tube includes an acute bend between the two cuffs and the two peritoneal tubes are straight. 
         FIG. 10  is a top plan view of a tenth embodiment of the bifurcated peritoneal catheter according to the present invention, wherein the entry tube is straight between the two cuffs and one of the two peritoneal tubes is coiled toward the other. 
         FIG. 11  is a top plan view of an eleventh embodiment of the bifurcated peritoneal catheter according to the present invention, wherein the entry tube is straight between the two cuffs and the two peritoneal tubes are coiled in the same direction. 
         FIG. 12  is a top plan view of a twelfth embodiment of the bifurcated peritoneal catheter according to the present invention, wherein the entry tube is straight between the two cuffs and one of the peritoneal tubes are coiled away from the other. 
         FIG. 13  is a top plan view of a thirteenth embodiment of the bifurcated peritoneal catheter according to the present invention, wherein the entry tube is straight between the two cuffs and the two peritoneal tubes are coiled away from each other. 
     
    
    
     Similar reference characters denote corresponding features consistently throughout the attached drawings. 
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS 
     The bifurcated peritoneal catheter provides a second internal catheter tube, i.e., within the peritoneal cavity of the patient, to provide a secondary or backup path for the introduction of dialysate fluid and the withdrawal of contaminated fluid during peritoneal dialysis. This greatly reduces the need for surgery to remove a single internal tube and to install a new tube in the patient, as there is a much greater likelihood that one of the two internal tubes will remain open. As both internal tubes perform the same function, fluid flow through the two internal tubes and the primary tube is always in the same direction at any given time, i.e., into the peritoneal cavity or out from the peritoneal cavity. A number of different embodiments are disclosed herein. 
       FIG. 1  of the drawings illustrates a top plan view of a first embodiment of the bifurcated peritoneal catheter, designated as bifurcated peritoneal catheter (or catheter)  100 . The catheter  100  includes a thin, elongate primary tube  102  having a closed wall  104  with an open proximal end  106  and an opposite open distal end  108 . Some portion of the length of the primary tube  102  to the proximal end  106  thereof extends externally from the patient to appropriate fluid delivery and collection points external to the patient during the dialysis procedure. The distal end portion  108  of the primary tube  102  is surgically implanted within the patient. 
     First and second internal tubes, respectively  110   a  and  110   b , are adapted for surgical placement within the peritoneal cavity of the patient. Each of these two internal tubes  110   a ,  110   b  comprise a long, thin element having a wall, respectively  112   a  and  112   b , with an open proximal end, respectively  114   a  and  114   b , and opposite open distal end, respectively  116   a  and  116   b . The proximal ends  114   a ,  114   b  of the two internal tubes  110   a ,  110   b  are joined to and communicate with the distal end  108  of the primary tube  102  and with one another and foil a small acute angle  118  between the two proximal ends  114   a ,  114   b , e.g., on the order of twenty to thirty degrees included angle therebetween. This greatly improves the fluid flow through the bifurcated catheter  100  by reducing fluid turbulence at the juncture of the tubes. It will be seen that this structure results in unidirectional flow of any fluid flowing within the catheter  100  at any given time, as fluid cannot flow in one direction through one of the internal tubes and in an opposite direction in the other of the internal tubes due to their common connection to and communication with the distal end  108  of the primary tube  102 . The walls  112   a ,  112   b  of the two internal tubes  110   a ,  110   b  have closed portions  120   a ,  120   b  extending for some lengths from points adjacent their proximal ends  114   a ,  114   b , but have porous portions  122   a ,  122   b  extending for some lengths from points adjacent their distal ends  116   a ,  116   b  to the closed wall portions  120   a ,  120   b  thereof. 
     In the catheter  100  example of  FIG. 1 , a single annular subcutaneous cuff  124  is located concentrically about the distal end  108  of the primary tube  102 , adjacent its juncture with the proximal ends  114   a  and  114   b  of the two internal tubes  110   a  and  110   b . This subcutaneous cuff  124  serves as a seal between the skin and body of the patient and the primary tube  102 . An additional cuff may be provided, as shown and described further below for other embodiments. It will also be noted in the catheter  100  example of  FIG. 1  that the first internal tube  110   a  is substantially straight, while the second internal tube  110   b  is curved away from the first internal tube  110   a . This configuration is exemplary and any practicable number of different straight, curved, and/or coiled internal tubes can be formed, with various examples illustrated in subsequent drawing Figs. and described below. 
       FIG. 2  of the drawings illustrates a second embodiment bifurcated peritoneal catheter  200 . The catheter  200  is configured similarly to the catheter  100  of  FIG. 1 , i.e., having a thin, elongate primary tube  202  with a closed wall  204 , open proximal end  206 , and opposite open distal end  208 . It will be seen that the length of the primary tube  202  is somewhat shorter than the length of the primary tube  102  of the catheter  100  of  FIG. 1 . The primary tube lengths of any of the bifurcated peritoneal catheters described herein, as well as their two internal catheters, can be formed or adjusted as desired. 
     First and second internal tubes, respectively  210   a  and  210   b , are also adapted for surgical placement within the peritoneal cavity of the patient. These two internal tubes  210   a ,  210   b  each comprise a long, thin element having a wall, respectively  212   a  and  212   b , with an open proximal end, respectively  214   a  and  214   b , and opposite open distal end, respectively  216   a  and  216   b . The proximal ends  214   a ,  214   b  of the two internal tubes  210   a ,  210   b  are joined to and communicate with the distal end  208  of the primary tube  202  and with one another and form a small acute angle  218  between the two proximal ends  214   a ,  214   b , e.g., on the order of twenty to thirty degrees included angle therebetween. The walls  212   a ,  212   b  of the two internal tubes  210   a ,  210   b  have closed portions  220   a ,  220   b  extending for some lengths from points adjacent their proximal ends  214   a ,  214   b , but have porous portions  222   a ,  222   b  extending for some lengths from points adjacent their distal ends  216   a ,  216   b  to the closed wall portions  220   a ,  220   b  thereof. A single annular subcutaneous cuff  224  is located concentrically about the distal end  208  of the primary tube  202 , adjacent its juncture with the proximal ends  214   a  and  214   b  of the two internal tubes  210   a  and  210   b.    
     It will be noted in the catheter  200  example of  FIG. 2  that both of the internal tubes  210   a  and  210   b  are curved away from one another. This, and the shorter length of the primary tube  202 , is the primary distinction between the bifurcated peritoneal catheter embodiment  100  of  FIG. 1  and the embodiment  200  of  FIG. 2 . 
       FIG. 3  of the drawings illustrates a third embodiment  300  of the bifurcated peritoneal catheter. The catheter  300  is configured similarly to the catheter  100  of  FIG. 1 , i.e., having a thin, elongate primary tube  302  with a closed wall  304 , open proximal end  306 , and opposite open distal end  308 . First and second internal tubes, respectively  310   a  and  310   b , extend from the distal end  308  of the primary tube  302 , with the first and second internal tubes each comprising a long, thin element having a wall, respectively  312   a  and  312   b , an open proximal end, respectively  314   a  and  314   b , and opposite open distal end, respectively  316   a  and  316   b . The proximal ends  314   a ,  314   b  of the two internal tubes  310   a ,  310   b  are joined to and communicate with the distal end  308  of the primary tube  302  and with one another and form a small acute angle  318  between the two proximal ends  314   a ,  314   b , e.g., on the order of twenty to thirty degrees included angle therebetween. The walls  312   a ,  312   b  of the two internal tubes  310   a ,  310   b  have closed portions  320   a ,  320   b  extending for some lengths from points adjacent their proximal ends  314   a ,  314   b , but have porous portions  322   a ,  322   b  extending for some lengths from points adjacent their distal ends  316   a ,  316   b  to the closed wall portions  320   a ,  320   b  thereof. The first internal tube  310   a  is straight and the second internal tube  310   b  is curved, as in the bifurcated peritoneal catheter embodiment  100  of  FIG. 1 . 
     The above-described structure of the third embodiment catheter  300  is essentially the same as that of the first embodiment catheter  100  of  FIG. 1 . However, it will be seen that the bifurcated peritoneal catheter  300  of  FIG. 3  includes two annular cuffs thereon. A first annular cuff  324  comprising a subcutaneous cuff is located about the medial portion  326  of the primary tube  302 , with a second or deep cuff  328  disposed about the distal end  308  of the primary tube  302  adjacent its juncture with the proximal ends  314   a  and  314   b  of the two internal tubes  310   a  and  310   b . The second or deep cuff  328  provides a secure passage for the distal end  308  of the primary tube  302  through the abdominal wall of the patient. 
       FIG. 4  of the drawings illustrates a fourth embodiment  400  of the bifurcated peritoneal catheter. The catheter  400  is configured similarly to the catheter  300  of  FIG. 3 , i.e., having a thin, elongate primary tube  402  with a closed wall  404 , open proximal end  406 , and opposite open distal end  408 . First and second internal tubes, respectively  410   a  and  410   b , extend from the distal end  408  of the primary tube  402 , with the first and second internal tubes each comprising a long, thin element having a wall, respectively  412   a  and  412   b , an open proximal end, respectively  414   a  and  414   b , and opposite open distal end, respectively  416   a  and  416   b . The proximal ends  414   a ,  414   b  of the two internal tubes  410   a ,  410   b  are joined to and communicate with the distal end  408  of the primary tube  402  and with one another and form a small acute angle  418  between the two proximal ends  414   a ,  414   b , e.g., on the order of twenty to thirty degrees included angle therebetween. The walls  412   a ,  412   b  of the two internal tubes  410   a ,  410   b  have closed portions  420   a ,  420   b  extending for some lengths from points adjacent their proximal ends  414   a ,  414   b , but have porous portions  422   a ,  422   b  extending for some lengths from points adjacent their distal ends  416   a ,  416   b  to the closed wall portions  420   a ,  420   b  thereof. The bifurcated peritoneal catheter embodiment  400  of  FIG. 4  differs from the embodiment  300  of  FIG. 3  in that both of the two internal tubes  410   a ,  410   b  have slight curvatures and are curved away from each other, as in the catheter embodiment  200  of  FIG. 2 . 
     The above-described structure of the fourth embodiment catheter  400  is essentially the same as that of the first embodiment catheter  200  of  FIG. 2 . However, it will be seen that the bifurcated peritoneal catheter  400  of  FIG. 4  includes two annular cuffs thereon. A first annular cuff  424  comprising a subcutaneous cuff is located about the medial portion  426  of the primary tube  402 , with a second or deep cuff  428  disposed about the distal end  408  of the primary tube  402  adjacent its juncture with the proximal ends  414   a  and  414   b  of the two internal tubes  410   a  and  410   b.    
       FIG. 5  of the drawings illustrates a fifth embodiment  500  of the bifurcated peritoneal catheter. The components of the catheter  500  are somewhat analogous to those of the catheter  400  of  FIG. 4 , i.e., having a thin, elongate primary tube  502  with a closed wall  504 , open proximal end  506 , and opposite open distal end  508 . First and second internal tubes, respectively  510   a  and  510   b , extend from the distal end  508  of the primary tube  502 , with the first and second internal tubes each comprising a long, thin element having a wall, respectively  512   a  and  512   b , an open proximal end, respectively  514   a  and  514   b , and opposite open distal end, respectively  516   a  and  516   b . The proximal ends  514   a ,  514   b  of the two internal tubes  510   a ,  510   b  are joined to and communicate with the distal end  508  of the primary tube  502  and with one another and form a small acute angle  518  between the two proximal ends  514   a ,  514   b , e.g., on the order of twenty to thirty degrees included angle therebetween. The walls  512   a ,  512   b  of the two internal tubes  510   a ,  510   b  have closed portions  520   a ,  520   b  extending for some lengths from points adjacent their proximal ends  514   a ,  514   b , but have porous portions  522   a ,  522   b  extending for some lengths from points adjacent their distal ends  516   a ,  516   b  to the closed wall portions  520   a ,  520   b  thereof. The bifurcated peritoneal catheter  500  of  FIG. 5  includes two annular cuffs thereon, as in the catheter embodiments  300  of  FIG. 3 and 400  of  FIG. 4 . A first annular cuff  524  comprising a subcutaneous cuff is located about the medial portion  526  of the primary tube  502 , with a second or deep cuff  528  disposed about the distal end  508  of the primary tube  502  adjacent its juncture with the proximal ends  514   a  and  514   b  of the two internal tubes  510   a  and  510   b.    
     The bifurcated peritoneal catheter embodiment  500  of  FIG. 5  differs from the embodiment  400  of  FIG. 4  in two different ways related to the orientation of the primary tube  502  and the two internal tubes  510   a  and  510   b . First, it will be seen that the primary tube  502  includes an acute bend or curvature  530  between the two cuffs  524  and  528 . (This is known as a “swan neck” curve in the field of the invention.) This assists in positioning the external portion of the primary tube  502  relative to the patient. Second, it will be seen that both of the porous wall portions  522   a  and  522   b  of the two internal tubes  510   a ,  510   b  are coiled, with the coiled portions subtending approximately 570 degrees, more or less. This provides a greater length of internal tube in a relatively small area, in order to more efficiently distribute dialysate fluid and draw contaminated fluid from the peritoneal cavity of the patient. In the example of  FIG. 5 , the first coiled portion  522   a  is coiled in a first direction, e.g., counterclockwise in the plan view of  FIG. 5 , with the second coiled portion  522   b  being coiled opposite the direction of the first coiled portion  522   a , i.e., clockwise for the second coiled portion. 
       FIG. 6  of the drawings illustrates a sixth embodiment  600  of the bifurcated peritoneal catheter. The components of the catheter  600  are somewhat analogous to those of the catheter  500  of  FIG. 5 , i.e., having a thin, elongate primary tube  602  with a closed wall  604 , open proximal end  606 , and opposite open distal end  608 . First and second internal tubes, respectively  610   a  and  610   b , extend from the distal end  608  of the primary tube  602 , with the first and second internal tubes each comprising a long, thin element having a wall, respectively  612   a  and  612   b , an open proximal end, respectively  614   a  and  614   b , and opposite open distal end, respectively  616   a  and  616   b . The proximal ends  614   a ,  614   b  of the two internal tubes  610   a ,  610   b  are joined to and communicate with the distal end  608  of the primary tube  602  and with one another and form a small acute angle  618  between the two proximal ends  614   a ,  614   b , e.g., on the order of twenty to thirty degrees included angle therebetween. The walls  612   a ,  612   b  of the two internal tubes  610   a ,  610   b  have closed portions  620   a ,  620   b  extending for some lengths from points adjacent their proximal ends  614   a ,  614   b , but have porous portions  622   a ,  622   b  extending for some lengths from points adjacent their distal ends  616   a ,  616   b  to the closed wall portions  620   a ,  620   b  thereof. The bifurcated peritoneal catheter  600  of  FIG. 6  includes two annular cuffs thereon, as in the catheter embodiments  300 ,  400 , and  500 , respectively of  FIGS. 3, 4 , and  FIG. 5 . A first annular cuff  624  comprising a subcutaneous cuff is located about the medial portion  626  of the primary tube  602 , with a second or deep cuff  628  disposed about the distal end  608  of the primary tube  602  adjacent its juncture with the proximal ends  614   a  and  614   b  of the two internal tubes  610   a  and  610   b.    
     The bifurcated peritoneal catheter embodiment  600  of  FIG. 6  differs from the embodiment  500  of  FIG. 5  due to the configurations of the internal tubes  610   a  and  610   b . It will be seen that the first internal tube  610   a  is straight, while the porous wall portion  612   b  of the second internal tube  610   b  is coiled, with the coiled portion subtending approximately 570 degrees, more or less. In the example of  FIG. 6 , the coiled portion  622   b  of the second internal tube  610   b  is coiled in a first direction, e.g., counterclockwise in the plan view of  FIG. 6 , resulting in its coil being toward the straight length of the first internal tube  610   a.    
       FIG. 7  of the drawings illustrates a sixth embodiment  700  of the bifurcated peritoneal catheter. The components of the catheter  700  are essentially similar to those of the catheter  600  of  FIG. 6 , i.e., having a thin, elongate primary tube  702  with a closed wall  704 , open proximal end  706 , and opposite open distal end  708 . First and second internal tubes, respectively  710   a  and  710   b , extend from the distal end  708  of the primary tube  702 , with the first and second internal tubes each comprising a long, thin element having a wall, respectively  712   a  and  712   b , an open proximal end, respectively  714   a  and  714   b , and opposite open distal end, respectively  716   a  and  716   b . The proximal ends  714   a ,  714   b  of the two internal tubes  710   a ,  710   b  are joined to and communicate with the distal end  708  of the primary tube  702  and with one another and form a small acute angle  718  between the two proximal ends  714   a ,  714   b , e.g., on the order of twenty to thirty degrees included angle therebetween. The walls  712   a ,  712   b  of the two internal tubes  710   a ,  710   b  have closed portions  720   a ,  720   b  extending for some lengths from points adjacent their proximal ends  714   a ,  714   b , but have porous portions  722   a ,  722   b  extending for some lengths from points adjacent their distal ends  716   a ,  716   b  to the closed wall portions  720   a ,  720   b  thereof. The bifurcated peritoneal catheter  700  of  FIG. 7  includes two annular cuffs thereon, as in the catheter embodiments  300  through  600 , respectively of  FIGS. 3 through 6 . A first annular cuff  724  comprising a subcutaneous cuff is located about the medial portion  726  of the primary tube  702 , with a second or deep cuff  728  disposed about the distal end  708  of the primary tube  702  adjacent its juncture with the proximal ends  714   a  and  714   b  of the two internal tubes  710   a  and  710   b.    
     The bifurcated peritoneal catheter embodiment  700  of  FIG. 7  differs from the embodiment  600  of  FIG. 6  due to the curvature or coil of the second internal tube  610   b . In the example of  FIG. 7 , the coiled portion  722   b  of the second internal tube  710   b  is coiled in a second direction, e.g., clockwise in the plan view of  FIG. 7 , resulting in its coil being away the straight length of the first internal tube  710   a.    
       FIG. 8  of the drawings illustrates an eighth embodiment  800  of the bifurcated peritoneal catheter. The components of the catheter  800  are quite similar to those of the catheter  500  of  FIG. 5 , i.e., having a thin, elongate primary tube  802  with a closed wall  804 , open proximal end  806 , and opposite open distal end  808 . First and second internal tubes, respectively  810   a  and  810   b , extend from the distal end  808  of the primary tube  802 , with the first and second internal tubes each comprising a long, thin element having a wall, respectively  812   a  and  812   b , an open proximal end, respectively  814   a  and  814   b , and opposite open distal end, respectively  816   a  and  816   b . The proximal ends  814   a ,  814   b  of the two internal tubes  810   a ,  810   b  are joined to and communicate with the distal end  808  of the primary tube  802  and with one another and form a small acute angle  818  between the two proximal ends  814   a ,  814   b , e.g., on the order of twenty to thirty degrees included angle therebetween. The walls  812   a ,  812   b  of the two internal tubes  810   a ,  810   b  have closed portions  820   a ,  820   b  extending for some lengths from points adjacent their proximal ends  814   a ,  814   b , but have porous portions  822   a ,  822   b  extending for some lengths from points adjacent their distal ends  816   a ,  816   b  to the closed wall portions  820   a ,  820   b  thereof. The bifurcated peritoneal catheter  800  of  FIG. 8  includes two annular cuffs thereon, as in the catheter embodiments  300  through  700  respectively of  FIGS. 3 through 7 . A first annular cuff  824  comprising a subcutaneous cuff is located about the medial portion  826  of the primary tube  802 , with a second or deep cuff  828  disposed about the distal end  808  of the primary tube  802  adjacent its juncture with the proximal ends  814   a  and  814   b  of the two internal tubes  810   a  and  810   b.    
     The bifurcated peritoneal catheter embodiment  800  of  FIG. 8  differs from the embodiment  500  of  FIG. 5  due to the orientation of the coiled porous portion  822   a  of the first internal tube  810   a . In  FIG. 8 , the coiled porous portion  822   a  of the first internal tube  810   a  is coiled in the same orientation or direction as the coiled porous portion  822   b  of the second internal tube  810   b , i.e., both are coiled in a first or clockwise orientation as viewed from the orientation shown in  FIG. 8 . 
       FIG. 9  of the drawings illustrates a ninth embodiment  900  of the bifurcated peritoneal catheter. The components of the catheter  900  are somewhat analogous to those of the catheter  500  of  FIG. 5 , but rather than the internal tubes of the catheter being coiled as in the catheter embodiment  500  of  FIG. 5 , the internal tubes of the catheter embodiment  900  of  FIG. 9  are straight. The catheter  900  has a thin, elongate primary tube  902  with a closed wall  904 , open proximal end  906 , and opposite open distal end  908 . First and second internal tubes, respectively  910   a  and  910   b , extend from the distal end  908  of the primary tube  902 , with the first and second internal tubes each comprising a long, thin element having a wall, respectively  912   a  and  912   b , an open proximal end, respectively  914   a  and  914   b , and opposite open distal end, respectively  916   a  and  916   b . The proximal ends  914   a ,  914   b  of the two internal tubes  910   a ,  910   b  are joined to and communicate with the distal end  908  of the primary tube  902  and with one another and form a small acute angle  918  between the two proximal ends  914   a ,  914   b , e.g., on the order of twenty to thirty degrees included angle therebetween. The walls  912   a ,  912   b  of the two internal tubes  910   a ,  910   b  have closed portions  920   a ,  920   b  extending for some lengths from points adjacent their proximal ends  914   a ,  914   b , but have porous portions  922   a ,  922   b  extending for some lengths from points adjacent their distal ends  916   a ,  916   b  to the closed wall portions  920   a ,  920   b  thereof. The bifurcated peritoneal catheter  900  of  FIG. 9  includes two annular cuffs thereon, as in the catheter embodiments  300  through  800  respectively of  FIGS. 3 through 8 . A first annular cuff  924  comprising a subcutaneous cuff is located about the medial portion  926  of the primary tube  902 , with a second or deep cuff  928  disposed about the distal end  908  of the primary tube  902  adjacent its juncture with the proximal ends  914   a  and  914   b  of the two internal tubes  910   a  and  910   b.    
     The bifurcated peritoneal catheter embodiment  900  of  FIG. 9  differs from the embodiment  800  of  FIG. 8  in that the two internal tubes  810   a  and  810   b  are both straight, and diverge from their juncture with the distal end  808  of the primary tube  802  by a constant small included angle, as described further above. Otherwise, the bifurcated peritoneal catheter  900  of  FIG. 9  is substantially the same as the bifurcated peritoneal catheter of  FIG. 8 . 
       FIG. 10  of the drawings illustrates a tenth embodiment  1000  of the bifurcated peritoneal catheter. The catheter  1000  is essentially a combination of the catheter  400  of  FIG. 4  with its straight primary tube and the catheter  600  of  FIG. 6  with its coiled perforated portion of the second internal tube. The catheter  1000  has a thin, elongate primary tube  1002  with a closed wall  1004 , open proximal end  1006 , and opposite open distal end  1008 . First and second internal tubes, respectively  1010   a  and  1010   b , extend from the distal end  1008  of the primary tube  1002 , with the first and second internal tubes each comprising a long, thin element having a wall, respectively  1012   a  and  1012   b , an open proximal end, respectively  1014   a  and  1014   b , and opposite open distal end, respectively  1016   a  and  1016   b . The proximal ends  1014   a ,  1014   b  of the two internal tubes  1010   a ,  1010   b  are joined to and communicate with the distal end  1008  of the primary tube  1002  and with one another and form a small acute angle  1018  between the two proximal ends  1014   a ,  1014   b , e.g., on the order of twenty to thirty degrees included angle therebetween. The walls  1012   a ,  1012   b  of the two internal tubes  1010   a ,  1010   b  have closed portions  1020   a ,  1020   b  extending for some lengths from points adjacent their proximal ends  1014   a ,  1014   b , but have porous portions  1022   a ,  1022   b  extending for some lengths from points adjacent their distal ends  1016   a ,  1016   b  to the closed wall portions  1020   a ,  1020   b  thereof. 
     The bifurcated peritoneal catheter embodiment  1000  of  FIG. 10  differs from the embodiment  400  of  FIG. 4  in that the first internal tube  1010   a  is straight, while the porous portion  1022   b  of the second internal tube  1010   b  is coiled toward the first internal tube  1010   a . This configuration of the internal tubes is similar to that of the sixth embodiment catheter  600  of  FIG. 6 . However, the catheter  1000  of  FIG. 10  is similar to the embodiments  300  of  FIG. 3 and 400  of  FIG. 4  in that the primary tube  1002  is straight, rather than having an acute bend or curve therein. It will also be seen that the bifurcated peritoneal catheter  1000  of  FIG. 4  includes two annular cuffs thereon, as in the embodiments  300  and  400  respectively of  FIGS. 3 and 4 . A first annular cuff  1024  comprising a subcutaneous cuff is located about the medial portion  1026  of the primary tube  1002 , with a second or deep cuff  1028  disposed about the distal end  1008  of the primary tube  1002  adjacent its juncture with the proximal ends  1014   a  and  1014   b  of the two internal tubes  1010   a  and  1010   b.    
       FIG. 11  of the drawings illustrates an eleventh embodiment  1100  of the bifurcated peritoneal catheter. The catheter  1100  is essentially a combination of the catheter  400  of  FIG. 4  with its straight primary tube and the catheter  800  of  FIG. 8  with its two coiled perforated portions of its two internal tubes. The catheter  1100  has a thin, elongate primary tube  1102  with a closed wall  1104 , open proximal end  1106 , and opposite open distal end  1108 . First and second internal tubes, respectively  1110   a  and  1110   b , extend from the distal end  1108  of the primary tube  1102 , with the first and second internal tubes each comprising a long, thin element having a wall, respectively  1112   a  and  1112   b , an open proximal end, respectively  1114   a  and  1114   b , and opposite open distal end, respectively  1116   a  and  1116   b . The proximal ends  1114   a ,  1114   b  of the two internal tubes  1110   a ,  1110   b  are joined to and communicate with the distal end  1108  of the primary tube  1102  and with one another and form a small acute angle  1118  between the two proximal ends  1114   a ,  1114   b , e.g., on the order of twenty to thirty degrees included angle therebetween. The walls  1112   a ,  1112   b  of the two internal tubes  1110   a ,  1110   b  have closed portions  1120   a ,  1120   b  extending for some lengths from points adjacent their proximal ends  1114   a ,  1114   b , but have porous portions  1122   a ,  1122   b  extending for some lengths from points adjacent their distal ends  1116   a ,  1116   b  to the closed wall portions  1120   a ,  1120   b  thereof. A first annular cuff  1124  comprising a subcutaneous cuff is located about the medial portion  1126  of the primary tube  1102 , with a second or deep cuff  1128  disposed about the distal end  1108  of the primary tube  1102  adjacent its juncture with the proximal ends  1114   a  and  1114   b  of the two internal tubes  1110   a  and  1110   b.    
     The bifurcated peritoneal catheter embodiment  1100  of  FIG. 11  differs from the embodiment  800  of  FIG. 8  in that the primary tube  1102  is straight, rather than having an acute bend or curve therein. The two perforated portions  1122   a  and  1122   b  of the internal tubes  1110   a  and  1110   b  are both coiled in the same direction, i.e., clockwise. This is the same orientation as the coils of the perforated portions  822   a ,  822   b  of the catheter embodiment  800  of  FIG. 8 , but the orientation may appear different in the embodiment  1100  of  FIG. 11  due to the straight primary tube  1102 . 
       FIG. 12  of the drawings illustrates a twelfth embodiment  1200  of the bifurcated peritoneal catheter. The catheter  1200  most closely resembles the catheter  1000  of  FIG. 10 , excepting the relative placement of the straight and curved internal tubes. The catheter  1200  has a thin, elongate primary tube  1202  with a closed wall  1204 , open proximal end  1206 , and opposite open distal end  1208 . First and second internal tubes, respectively  1210   a  and  1210   b , extend from the distal end  1208  of the primary tube  1202 , with the first and second internal tubes each comprising a long, thin element having a wall, respectively  1212   a  and  1212   b , an open proximal end, respectively  1214   a  and  1214   b , and opposite open distal end, respectively  1216   a  and  1216   b . The proximal ends  1214   a ,  1214   b  of the two internal tubes  1210   a ,  1210   b  are joined to and communicate with the distal end  1208  of the primary tube  1202  and with one another and form a small acute angle  1218  between the two proximal ends  1214   a ,  1214   b , e.g., on the order of twenty to thirty degrees included angle therebetween. The walls  1212   a ,  1212   b  of the two internal tubes  1210   a ,  1210   b  have closed portions  1220   a ,  1220   b  extending for some lengths from points adjacent their proximal ends  1214   a ,  1214   b , but have porous portions  1222   a ,  1222   b  extending for some lengths from points adjacent their distal ends  1216   a ,  1216   b  to the closed wall portions  1220   a ,  1220   b  thereof. A first annular cuff  1224  comprising a subcutaneous cuff is located about the medial portion  1226  of the primary tube  1202 , with a second or deep cuff  1228  disposed about the distal end  1208  of the primary tube  1202  adjacent its juncture with the proximal ends  1214   a  and  1214   b  of the two internal tubes  1210   a  and  1210   b.    
     The bifurcated peritoneal catheter embodiment  1200  of  FIG. 12  differs from the embodiment  1000  of  FIG. 10  in that the porous portion  1222   a  of the first internal tube  1210   a  is coiled, while the second internal tube  1210   b  is straight. The orientation of the porous coiled portions  1022   b  of the embodiment of  FIGS. 10 and 1222   a  of the embodiment of  FIG. 12  is the same, i.e., clockwise in both cases. It will be seen that this orients the coil of the second internal tube  1010   b  of the embodiment of  FIG. 10  toward the opposite first internal tube  1010   a , while the coil of the first internal tube  1210   a  of the embodiment of  FIG. 12  is oriented away from the opposite second internal tube  1210   b.    
       FIG. 13  of the drawings illustrates a thirteenth embodiment  1300  of the bifurcated peritoneal catheter. The catheter  1300  is similar to the catheter  1100  of  FIG. 11 , excepting the orientation of the porous coiled portion of the second internal tube. The catheter  1300  has a thin, elongate primary tube  1302  with a closed wall  1304 , open proximal end  1306 , and opposite open distal end  1308 . First and second internal tubes, respectively  1310   a  and  1310   b , extend from the distal end  1308  of the primary tube  1302 , with the first and second internal tubes each comprising a long, thin element having a wall, respectively  1312   a  and  1312   b , an open proximal end, respectively  1314   a  and  1314   b , and opposite open distal end, respectively  1316   a  and  1316   b . The proximal ends  1314   a ,  1314   b  of the two internal tubes  1310   a ,  1310   b  are joined to and communicate with the distal end  1308  of the primary tube  1302  and with one another and form a small acute angle  1318  between the two proximal ends  1314   a ,  1314   b , e.g., on the order of twenty to thirty degrees included angle therebetween. The walls  1312   a ,  1312   b  of the two internal tubes  1310   a ,  1310   b  have closed portions  1320   a ,  1320   b  extending for some lengths from points adjacent their proximal ends  1314   a ,  1314   b , but have porous portions  1322   a ,  1322   b  extending for some lengths from points adjacent their distal ends  1316   a ,  1316   b  to the closed wall portions  1320   a ,  1320   b  thereof. A first annular cuff  1324  comprising a subcutaneous cuff is located about the medial portion  1326  of the primary tube  1302 , with a second or deep cuff  1328  disposed about the distal end  1308  of the primary tube  1302  adjacent its juncture with the proximal ends  1314   a  and  1314   b  of the two internal tubes  1310   a  and  1310   b.    
     The bifurcated peritoneal catheter embodiment  1300  of  FIG. 13  differs from the embodiment  1100  of  FIG. 11  in that the porous coiled portion  1322   b  of the second internal tube  1310   b  is coiled in the opposite direction from the corresponding portion  1322   a  of the first internal tube  1310   a , i.e., counterclockwise, with the coiled porous portion  1322   a  of the first internal tube being coiled clockwise. In other words, the first and second internal tubes  1310   a ,  1310   b  are coiled away from one another. 
     It will be seen that further permutations and combinations of the bidirectional peritoneal catheter can be provided in addition to those illustrated in the drawing Figs. and described above. Such permutations and combinations can include one or two cuffs, straight or curved primary tubes, various combinations of straight and curved or coiled internal tubes, etc., as desired. 
     It is to be understood that the present invention is not limited to the embodiments described above, but encompasses any and all embodiments within the scope of the following claims.