US20040049288A1 - Prosthesis for internal peritoneal dialysis and method of providing peritoneal dialysis - Google Patents

Abstract

Continuous internal peritoneal dialysis prosthesis and method employing an abdominal sac adapted to be retained in the abdominal region of a patient's body and including dialysate therein for permitting unconcentrated urine within the peritoneal region to pass through a semi-permeable membrane wall of the abdominal sac. The unconcentrated urine within the abdominal sac is directed through a section of the patient's bowel and is communicated with the internal wall of the bowel to thereby concentrate the urine. The concentrated urine is then directed into the urinary bladder for subsequent excretion from the patient's body. In the preferred prosthesis and method of this invention the normal breathing pattern of the patient is employed to assist in the circulation of the unconcentrated urine from the abdominal sac into and through the section of the patient's bowel. In alternative embodiments, the dialysate may be contained within the abdominal sac, contained within the prosthesis, or allowed to directly contact the peritoneum.

Description

SPECIFICATION
• This application is a Continuation-In-Part of U.S. patent application Ser. No. 09/833,286, filed Apr. 12, 2001, and entitled “Prosthesis for Internal Peritoneal Dialysis and Method of Providing Peritoneal Dialysis”; which is a Continuation-In-Part of U.S. patent application Ser. No. 09/693,591, filed Oct. 20, 2000, and entitled “Prosthesis for Continuous Internal Peritoneal Dialysis and Continuous Method of Providing Peritoneal Dialysis.”[0001]
FIELD OF THE INVENTION
• This invention relates to generally to prosthesis for continuous internal peritoneal dialysis and a continuous method of carrying out peritoneal dialysis. More specifically, this invention relates to artificial kidneys, and more specifically to artificial kidneys implantable within a person's body with the intent that the patient be free from dialysis and transplantation. The artificial kidneys of this invention employ the normal operation of the person's body (i.e., breathing cycle of the person) to cause the flow of fluid within the prosthesis for the removal of toxic substances or other fluids from the person's body. For the treatment of edema states that are refractory to treatment with diuretics the dialysate can be a selected hypertonic solution for removing excess fluids; principally water.[0002]
BACKGROUND OF THE INVENTION
• The dialysis art is a highly developed one; providing a variety of teachings for dialyzing a patient.[0003]
• In accordance with a related dialysis procedure (e.g., hemodialysis) for purifying blood in a patient experiencing kidney failure, the contaminated blood is directed from a blood vessel of the patient's arm through a dialyzing membrane located extracorporeally of the body, in which the blood gives up its impurities to the dialyzing fluid. The purified blood is then directed back into the patient's body through another blood vessel. A representative disclosure of a system for use in purifying arterial blood and providing a venous return is disclosed in U.S. Pat. No. 3,579,441, issued to Brown.[0004]
• The dialysis art also suggests the use of related peritoneal dialysis systems, wherein a dialysate is introduced directly into the abdomen of the patient and functions to receive impurities from the blood at the abdominal capillaries, and then is mechanically removed from the body. Representative peritoneal dialysis systems of this type are disclosed in U.S. Pat. No. 4,681,564 (Landreneau); U.S. Pat. No. 4,655,762 (Rogers); U.S. Pat. No. 4,586,920 (Peabody) and U.S. Pat. No. 4,437,856 (Valli).[0005]
• All of the related art systems known to applicants suffer from one or more disadvantages. For example, a number of prior art systems require that the patient be connected, e.g., “hooked-up”, to a dialysis machine. This renders the patient immobile during treatment, is expensive to administer, and subjects the patient to a high risk of infection, and even death. Patients are protein restricted, because protein yields toxic degradation products (e.g., nitrogenous wastes) largely responsible for uremia, the state of being in kidney failure. Toxic levels of potassium may also result from the treatment. Moreover, chronic contact of the peritoneum with hypertonic dialysate solutions often creates chronic peritonitis, which is a painful, dangerous condition that interferes with the peritoneal dialysis process.[0006]
• The absorption of dialysate into the bloodstream interferes with the peritoneum dialysate's ability to do its job of pulling in fluids. Therefore, peritoneal dialysis relies physiologically on the fact that the dialysis fluid in the abdominal cavity is more viscous or thicker than blood. In other words, the dialysis fluid has a higher osmolality or chemical potential than the bloodstream. This difference in potential causes water and other molecules known to those skilled in the art to diffuse into the abdomen via the semi-permeable membranes of the peritoneum and mesenteric parietes which line the abdominal cavity.[0007]
• Additionally, all previous modes of dialysis have been essentially intermittent, rather than continuous; resulting in a variety of disturbances to the body's equilibrium. Patients become either over-hydrated or under-hydrated due to the intermittent process of adding and removing fluids. The systems can not maintain proper blood volume and chemical balance beyond the few hours following the treatment. The treatments sap the patient's energy and sense of well-being, making the patient look and feel chronically ill, and critically affecting the patient's lifestyle, happiness and longevity.[0008]
• With respect to transplantation, the high cost and risks are well known. A match for the patient must be found, which may take years. If a kidney is found, and the patient is still strong enough to receive it, then there is no guarantee that the kidney will be accepted. The patient's immune system may recognize a kidney transplanted from another as foreign matter and act to combat and reject this perceived invasion. Anti-rejection medication, such as azathioprine, cyclosporine and steroids help to prevent rejection. However, anti-rejection medicines have a large number of side effects. If rejection occurs, treatment is available to possibly reverse the episode, but at the cost of more medication and side effects. With kidney transplantation, about one third of the patients do very well, about one third remain chronically ill, and about one third of the patients die within five years.[0009]
• A need clearly exists for an artificial kidney, or prosthesis, that is lower in cost than existing systems, that can be utilized with a minimum of risk to the patient, that provides greater freedom of movement for the patient and that allows for the continuous formation of urine as in a normal functioning kidney. Therefore, it would be beneficial to provide a continuous internal peritoneal dialysis prosthesis and method. It would also be beneficial to provide a continuous internal peritoneal dialysis prosthesis and method which employs the normal breathing pattern of the patient to affect the dialysis operation, which is simple in operation and requires relatively few moving parts.[0010]
• To applicant's knowledge, prior to this invention, there has been no artificial kidney that is implantable in the body to provide any of the functions normally provided by a healthy kidney. It is to such artificial kidneys that the present invention is directed.[0011]
SUMMARY OF THE INVENTION
• This invention includes a continuous internal peritoneal dialysis prosthesis and method employing an abdominal sac including a dialysate therein, the abdominal sac being adapted to be retained in the abdominal region of a person's body for receiving unconcentrated urine through the walls of the sac without permitting dialysate to exit from the sac through the walls. The abdominal sac communicates the unconcentrated urine through a section of the patient's bowel via at least one conduit that extends through the section of bowel. A region of the conduit within the section of the patient's bowel includes apertures therein for communicating the unconcentrated urine in the conduit with walls of the section of bowel; thereby employing the natural function of the bowel to concentrate the urine.[0012]
• In another preferred embodiment, this invention includes a continuous internal peritoneal dialysis prosthesis and method employing an abdominal sac, a fluid guide conduit and a conduit extension. The abdominal sac is adapted to include a dialysate therein. The abdominal sac includes a semi-permeable membrane outer wall, and is adapted to be retained in the abdominal region of a patient's body with the semi-permeable membrane outer wall being in communication with unconcentrated urine in the abdominal region for receiving unconcentrated urine through the semi-permeable membrane outer wall without permitting dialysate to exit through the outer wall. The fluid guide conduit is adapted to receive the unconcentrated urine and dialysate from the abdominal sac and to communicate the dialysate back into the abdominal sac for recirculation. The conduit extension extends from the fluid guide conduit and is adapted to receive the unconcentrated urine from the fluid guide conduit. The conduit extension is also adapted to extend into and terminate in a section of the patient's bowel separated from the patient's GI tract to communicate the unconcentrated urine in the conduit extension with the section of bowel for concentrating the urine within the section of bowel.[0013]
• A continuous internal peritoneal dialysis method of this invention includes containing unconcentrated urine in the abdominal region of a patient, and directing the contained unconcentrated urine into a section of bowel in which the urine is concentrated for removal from the patient.[0014]
• Further scope of applicability of the present invention will become apparent from the description given hereinafter. However, it should be understood that the detailed description and specific examples, while indicating preferred embodiments of the invention, are given by way of illustration only, since the invention will become apparent to those skilled in the art from this detailed description.[0015]
BRIEF DESCRIPTION OF THE DRAWINGS
• The invention will be described in conjunction with the following drawings in which like reference numbers designate like elements, and wherein:[0016]
• FIG. 1 is a front view of a continuous internal peritoneal dialysis prosthesis of a preferred embodiment of the present invention showing parts thereof in section and being located in a person's body;[0017]
• FIG. 2 is a front view of a continuous internal peritoneal dialysis prosthesis of another preferred embodiment of the present invention showing parts thereof in section and being located in a person's body;[0018]
• FIG. 3 is a front view of a continuous internal peritoneal dialysis prosthesis of a third embodiment of the present invention showing parts thereof in section and being located in a person's body;[0019]
• FIG. 4 is a front view of a continuous internal peritoneal dialysis prosthesis of a fourth embodiment of the present invention showing parts thereof in section and being located in a person's body;[0020]
• FIG. 5 is a front view of a continuous internal peritoneal dialysis prosthesis of a fifth embodiment of the present invention showing parts thereof in section and being located in a person's body;[0021]
• FIG. 6 is a front view of an internal peritoneal dialysis prosthesis of a sixth embodiment of the present invention showing parts thereof in section and being located in a person's body;[0022]
• FIG. 7 is a front view of a continuous internal peritoneal dialysis prosthesis of a seventh embodiment of the present invention showing parts thereof in section and being located in a person's body;[0023]
• FIG. 8 is a front view of a continuous internal peritoneal dialysis prosthesis of an eighth embodiment of the present invention showing parts thereof in section and being located in a person's body;[0024]
• FIG. 9 is a front partial view of an internal peritoneal dialysis prosthesis of a ninth preferred embodiment of the present invention showing parts thereof in section; and[0025]
• FIG. 10 is a front view of a continuous internal peritoneal dialysis prosthesis of a tenth embodiment of the present invention showing parts thereof in section and being located in a person's body.[0026]
DETAILED DESCRIPTION OF THE INVENTION
• Referring to FIG. 1, an exemplary continuous internal peritoneal dialysis prosthesis inserted within a patient's body is schematically illustrated at[0027]10. Theprosthesis10 includes an abdominal sac12 in the abdominal region of the patient belowdiaphragm14, athoracic pouch16 in the thoracic region of a patient's body above thediaphragm14, a section of a patient'sbowel18 located within the abdominal section of the patient, and the patient'surinary bladder20 connected to a downstream end of thebowel18 through the patient's cecum orappendix22 and distalright ureter24.
• Still referring to FIG. 1, the abdominal sac[0028]12 is connected to thethoracic pouch16 through aconduit26 including a one-way valve28 therein. The one-way valve28 permits fluid (e.g., unconcentrated urine) to flow only in the direction ofarrow30 from the abdominal sac12 into thethoracic pouch16.
• The abdominal sac[0029]12 includes a semi-permeableouter wall56 and an impermeableouter wall58 separated by asemi-permeable window34. The region of the abdominal sac12 defined by the semi-permeableouter wall56 and thesemi-permeable window34 is adialysis sac32. The impermeableouter wall58 includes afirst port60 for receiving a proximal end of theconduit26. After theconduit26 is in communication with theport60, the wall of the abdominal sac12 is stitched about theconduit26 to retain the conduit within theport60.
• Still referring to FIG. 1, the[0030]prosthesis10 includes asecond conduit36 that is connected to thethoracic pouch16 and passes through thediaphragm14 into and through a section of the patient'sbowel18. Thesecond conduit36 also includes a one-way valve38 to permit the unconcentrated urine to flow from thethoracic pouch16 through the section of the patient'sbowel18 only in the direction of thearrow40.
• As can be seen in FIG. 1, the patient's[0031]bowel18 includes end sections sutured to theconduit36 at both theentrance42 to thebowel18 and theexit44 from thebowel18. Thedistal end46 of thesecond conduit36 extends through a lower end of thebowel18 and is connected to the abdominal sac12 to recycle the flow of unconcentrated (or partially concentrated) urine back into the abdominal sac12, as will be described in greater detail below. Thedistal end46 is provided with a one-way valve48 to permit the urine to flow only in the direction ofarrow49 from the patient'sbowel18 to the abdominal sac12.
• As noted earlier, the abdominal sac[0032]12 is formed of an impermeable membrane atouter wall58, and a semi-permeable membrane atouter wall56 andwindow34. The semi-permeableouter wall56 andwindow34 define thedialysis sac32 of the abdominal sac12. The semi-permeable membrane has pores or apertures (holes) that provide the membrane with a porosity which precludes dialysate within thedialysis sac32 from escaping into the peritoneal region, but still permits unconcentrated urine within the peritoneal region to enter thedialysis sac32 through osmotic pressure. The porosity of thesemi-permeable window34 also precludes dialysate within thedialysis sac32 from filtering through thesemi-permeable window34 into the region of the abdominal sac12 in communication with theconduits26 and36. Therefore, in this example of the preferred embodiment, the dialysate is contained within thedialysis sac32. Because the abdominal sac12 is required to function in an aqueous environment, it preferably is formed of a synthetic plastic material with some elastic qualities. However, thedialysis sac32 should not be so elastic as to expand to an extent that permits the dialysate molecules or microstructures to exit from expanded pores of its walls.
• In order to prevent the[0033]dialysis sac32 from expanding to an extent that permits the dialysate to exit its walls, portions of the semi-permeableouter wall56 andwindow34 may alternatively be formed of an impermeable or substantially impermeable membrane that is more elastic than the semi-permeable membrane and does not permit the dialysate to exit, even when the impermeable or substantially impermeable membrane is expanded beyond its elastic limit. Therefore, before the semi-permeable membrane expands under pressure to an extent that could permit dialysate to exit, the impermeable or substantially impermeable membrane stretches to contain the dialysate while inhibiting the dialysate from exiting therefrom. Also,impermeable wall58 could be made elastic andsemi-permeable walls56 and34 inelastic.
• In an exemplary environment of this invention, the dialysate exerts chemical potential to draw in unconcentrated urine (e.g., fluid wastes, electrolytes, etc.) via the adjacent peritoneum and mesenteric parieties. The dialysate can be a large inert molecule or microstructure, e.g., microspheres, such as a 50 micron polyelectrolyte or L-racemate of any giant inert molecule which cannot exit the sac. It should be understood that, in accordance with the broadest aspects of this invention, the specific dialysate employed does not constitute a limitation on the present invention. However, the particle size of the dialysate must be such that the dialysate does not escape through the semi-permeable membrane walls of the[0034]dialysis sac32 during operation of theprosthesis10.
• Ideally, the pores or apertures in the semi-permeable membrane should be about 10 microns non-expanded to about 20 microns expanded, while the dialysis molecule should have a nominal size in the range of 50 to 100 microns. Of course, these numerical values are disclosed for purposes of illustration only, and are not intended to limit the scope of the present invention.[0035]
• The semi-permeable membrane can be made of any suitable synthetic plastic material, such as a Gortex-like cloth, and the dialysate can be made from a wide variety of molecules or microstructures well-known to those skilled in the art. The[0036]thoracic pouch16,first conduit26,second conduit36 and impermeableouter wall58 of the abdominal sac12 are preferably made from silicon plastic, which is inert and does not cause peritoneal irritation.
• In the preferred form of this invention, the[0037]dialysis sac32 is positioned between the peritoneum and mesenteric parieties in the left lower quadrant of the abdomen to extract fluids (unconcentrated urine) via osmotic diffusion and ultra filtration by the same physiological principles that control regular peritoneal dialysis. Thedialysis sac32 swells with unconcentrated urine which then traverses thewindow34 shared with the abdominal sac12. As shown in FIG. 1, the dialysate does not leave thedialysis sac32 and therefore cannot be absorbed by the lymphatic system or irritate the peritoneum. The unconcentrated urine entering thedialysis sac32 through the semi-permeable membrane and exiting through thewindow34 will then be directed through thefirst conduit26 and the one-way valve28, through thediaphragm14 and into thethoracic pouch16 by the internal body pumping mechanism based on relative pressure changes in the abdomen and thorax during the breathing cycle, as described later in this application. It should be understood that neither theconduit26 nor thethoracic pouch16 have any permeability, i.e., they are impermeable so as to preclude the escape of any unconcentrated urine therefrom.
• As is shown in FIG. 1, the abdominal sac[0038]12 and thethoracic pouch16 communicate withsubcutaneous access reservoirs50 and51, respectively, each of which include an access section closely adjacent the patient's skin. The subcutaneous access reservoirs (SARs)50 and51, permit the monitoring and testing of the urine in order to determine the effectiveness of the prosthesis. Thesubcutaneous access reservoirs50 and51 provide adjustments of urine flow and urine constituents by adding or subtracting dialysate to fit each patient's needs. The dialysate can be added or withdrawn from thesubcutaneous access reservoirs50 and51 using a syringe or tube inserted through the patient's skin into the reservoirs.
• The unconcentrated urine within the[0039]thoracic pouch16 then passes through thesecond conduit36 and one-way valve38 therein to a section of the patient'sbowel18. Movement of the unconcentrated urine from thethoracic pouch16 through thesecond conduit36 takes place by an internal pumping mechanism to be described in greater detail hereinafter. Suffice it to state at this time that thesecond conduit36 traverses a relatively long segment of bowel that has been isolated from the rest of the bowel. The segment that preferably is selected includes the right colon and ileum, and is capable of 90% water reabsorption in the bowel, which translates to 10 to 20 liters of water per day.
• The movement of the unconcentrated urine through the[0040]bowel18 is a unique feature of the present invention. Thesecond conduit36, which directs the unconcentrated urine into the segment of the patient'sbowel18 includes a series of relatively large holes (or apertures)54, e.g., one-half cm, so as to allow the unconcentrated urine within theconduit36 to move into thebowel18, wherein thebowel18 functions to reabsorb water, electrolytes and small molecules, resulting in the formation of concentrated urine. The bowel will not absorb large molecules, standard excretory wastes and other poisons, or even standard proteins. It should be noted that the jejunum is anastomosed to transverse colon to restore the integrity of the GI tract, and therefore, though the section patient'sbowel18 is isolated, its blood supply remains intact so as to permit it to function in this invention.
• Some of the concentrated urine will traverse the[0041]appendix22, which has a one-way peristalsis to thebladder20, which appropriately excretes the concentrated urine based on the bladder's normal function. The remaining urine is returned through thedistal end46 of theconduit36 to the abdominal sac12 for recirculation and recleansing. Thisdistal end46 of theconduit36 is impermeable to preclude the escape of any urine therefrom.
• It is important to note that in this exemplary prosthesis of this preferred embodiment, there is no free dialysate in the peritoneal cavity; the dialysate being retained in the[0042]dialysate sac32. It is only in such a system that it is both safe and advantageous for there to be emphatic reabsorption.
• In fact, it should be noted that in prior art peritoneal dialysis the reabsorption of dialysate and unconcentrated urine creates a major problem for two reasons. First, it interferes with the vary process of discarding this excessive fluid. Second, any system in which dialysate is reabsorbed causes two other problems, the first of which is that it interferes with the very difference in osmotic pressure needed for the whole process of diffusion and ultra filtration, and secondarily, even if the dialysate molecule is inert versus the sugar, salt or albumin used in standard dialysis, each of which causes its own special problems when reabsorbed by the lymphatic system, it creates a tremendous problem with oncotic pressure.[0043]
• Therefore, it should be emphasized that the continuous internal peritoneal dialysis prosthesis and method of this preferred embodiment is highly advantageous because the dialysate itself is separate at all times from the peritoneal space and from lymphatic absorption. The fact that some partially concentrated urine is recycled in the present invention is also advantageous. In particular, this recycling of partially concentrated urine allows for further cleansing of nitrogenous wastes from the urine and is precisely the same thing that happens during urine formation in a kidney that is functioning normally.[0044]
• It also should be noted that, in a manner identical to the functioning of a normal kidney, the lower the serum osmolality (the more liquids a patient consumes) the better the peritoneal system of this invention works. In particular, the greater the differential between the osmotic pressure in the[0045]dialysis sac32 employed in this invention and the blood (serum osmolality) the more urine is made. Therefore, the patient employing the prosthesis of this invention is able to drink as much as he or she wants, unlike other dialysis patients, because his/her increased intake of water simply increases the performance of the prosthesis of this invention. This is a significant benefit of the present invention.
• As noted earlier, when the unconcentrated urine is turned into concentrated urine within the section of the patient's[0046]bowel18, most of the concentrated urine will exit to the distalright ureter24, which can be attached to the cecum orappendix22 when appropriate, and this concentrated urine, of course, would then go into theurinary bladder20 to be expelled intermittently, just as in a normally functioning human patient.
• It should be noted that the process is continuous and prevents sudden changes in volume and concentration of the blood's constituents. The continuous operation of the prosthesis of this invention relies upon the internal body pumping action of the disclosed system. This internal body pumping action is a variation of the internal body pump and systems disclosed in Applicant's U.S. Pat. No. 5,813,410. The entire subject matter of this latter patent is hereby incorporated by reference herein.[0047]
• However, by way of explanation, the fluid is circulated through the[0048]prosthesis10 of this invention by means of a body-operated pump, e.g., the abdominal sac12 andthoracic pouch16 serve as pumps operated by a patient's breathing pattern to cause the fluid to flow through the prosthesis. In particular, fluid flow within theprosthesis10 is created by taking advantage of the normal function of a person'sdiaphragm14 and the normal internal pressure relationships that exist between the thoracic cavity and the abdominal cavity of the person's body while a person is breathing. Specifically, during inspiration (inhaling) the diaphragm, which separates the thoracic and abdominal cavities, is forced to descend; thereby leading to an increase in the intra thoracic volume and a corresponding decrease in the intra thoracic pressure. Conversely, the volume of the abdominal cavity decreases and the pressure in that cavity increases. This action forces fluid from the abdominal sac12 located in the abdominal cavity throughconduit26 and into thethoracic pouch16 in the thoracic cavity. The flow from the abdominal sac12 to thethoracic pouch16 is limited to flowing through theconduit26 only in the direction ofarrow30, due to the arrangement of the one-way valve28 in thatconduit26.
• Upon expiration (exhaling) the operation of the diaphragm is reversed. That is, the diaphragm is forced to rise; thereby leading to a decrease in the intra thoracic volume and the corresponding increase in the intra thoracic pressure. Conversely, during expiration, the volume of the abdominal cavity increases and the pressure in that cavity decreases. This action forces fluid from the[0049]thoracic pouch16, located in the thoracic cavity, preferably in the costo phrenic sulcus thereof, to flow through theconduit36, and into the section of the patient'sbowel18 for delivery into theurinary bladder20 or back into the abdominal sac12. Fluid flow from thethoracic pouch16 through thebowel section18 is limited to flowing only in the direction ofarrow40, due to the inclusion of the one-way valve38 in thesecond conduit36. Likewise, fluid flow from thebowel section18 to the abdominal sac12 is limited to flowing only in the direction ofarrow49, due to the inclusion of the one-way valve48.
• As should be appreciated from the foregoing, in operation the unconcentrated urine which is directed into the[0050]dialysis sac32 is continuously moved through theprosthesis10 by the breathing cycle of a patient, as described. The unconcentrated urine directed through thesecond conduit36 into thebowel section18 is then processed by the bowel section to concentrate the urine for ultimate removal through theurinary bladder20.
• If necessary, or desired, the pumping action provided by the breathing cycle of the patient can be augmented, or even supplanted, by another device, e.g., a mechanical or electrical pump implanted in the person's body in fluid communication with the loop of circulating fluid.[0051]
• Referring to FIG. 2, there is shown at[0052]62, an exemplary continuous internal peritoneal dialysis prosthesis inserted within a patient's body in accordance with a second preferred embodiment of this invention, which is similar to theprosthesis10 discussed above and illustrated in FIG. 1. As shown in FIG. 2, theprosthesis62 includes anabdominal sac64 in the abdominal region of the patient belowdiaphragm14, athoracic pouch16 in the thoracic region of the patient's body above thediaphragm14, a section of the patient'sbowel18 located within the abdominal section of the patient, and the patient'surinary bladder20 connected to a downstream end of thebowel18 through the patient's cecum orappendix22 and distalright ureter24. Theabdominal sac64 is connected to thethoracic pouch16 through aconduit26, including a one-way valve28 therein. The one-way valve28 permits fluid to flow only in the direction ofarrow30 from theabdominal sac64 into thethoracic pouch16.
• The[0053]prosthesis62 includes asecond conduit36 having aproximal end68 and adistal end46. Thissecond conduit36 is connected to thethoracic pouch16 through itsproximal end68 and passes through thediaphragm14 into and through a section of the patient'sbowel18. The second conduit includes a one-way valve38 at itsproximal end68 to permit the unconcentrated urine to flow from thethoracic pouch16 through the section of the patient'sbowel18 only in the direction ofarrow40. Thedistal end46 of thesecond conduit36 extends through a lower end of thebowel18 and is connected to theabdominal sac64 to recycle the flow of unconcentrated (or partially concentrated) urine back into theabdominal sac64. Thedistal end46 is provided with a one-way valve48 to permit the urine to flow only in the direction ofarrow49 from the patient'sbowel18 to theabdominal sac64. The patient'sbowel18 is sutured to theconduit36 at both theentrance42 to thebowel18 and theexit44 from thebowel18.
• As noted above, the[0054]prosthesis62 shown in FIG. 2 is constructed similar to theprosthesis10 shown in FIG. 1. However, in this embodiment, the dialysate is not contained only within a dialysis sac. In fact, theabdominal sac64 does not include or share a window with a dialysis sac. In FIG. 2, theabdominal sac64,thoracic pouch16 andconduits26 and36 provide a closed system for the dialysate, allowing the dialysate to cycle within theprosthesis62, but preventing the dialysate from leaving theprosthesis62.
• The[0055]abdominal sac64 is generally formed of a semi-permeable membrane having a porosity which precludes the dialysate within theabdominal sac64 from escaping into the peritoneal region, but still permits unconcentrated urine within the peritoneal region to enter theabdominal sac64 through osmotic pressure. Because theabdominal sac64 is required to function in an aqueous environment, it preferably is formed of a synthetic plastic material with some elastic qualities (e.g., Gortex-like cloth). However, theabdominal sac64 should not be so elastic as to expand to an extent that permits the dialysate molecules or microstructures to exit from expanded pores of its walls.
• The[0056]abdominal sac64 may be similar to the abdominal sac12 shown in FIG. 1, but without thewall34. As with the abdominal sac12 of FIG. 1, portions of the wall of theabdominal sac64 may alternatively be formed of an impermeable or substantially impermeable membrane that is more elastic than the semi-permeable membrane and does not permit the dialysate to exit, even when the impermeable or substantially impermeable membrane is expanded beyond its elastic limit. Therefore, before the semi-permeable membrane expands under pressure to an extent that could permit dialysate to exit, the impermeable or substantially impermeable membrane stretches to contain the dialysate while inhibiting the dialysate from exiting therefrom.
• As noted earlier, the section of the patient's[0057]bowel18 is sutured to theconduit36 at both theentrance42 to thebowel18 and theexit44 from thebowel18, thereby enclosing acentral region66 of theconduit36. Thiscentral section66 includes a semi-permeable wall so as to allow the unconcentrated urine within the central region of thesecond conduit36 to move into thebowel18, wherein the bowel functions to reabsorb water, electrolytes and small molecules, resulting in concentrated urine. However, the semi-permeable wall prevents the dialysate from moving into the bowel, thus keeping the dialysate within theprosthesis62. It should be understood that neither theconduit26, thethoracic pouch16, nor theproximal end68 of theconduit36 have any permeability, i.e., they are impermeable so as to preclude the escape of any unconcentrated urine or dialysate therefrom.
• As is shown in FIG. 2, the unconcentrated urine entering the[0058]abdominal sac64 through the semi-permeable membrane, and the dialysate are directed through thefirst conduit26 and the one-way valve28, through thediaphragm14 and into thethoracic pouch16 by the internal body pumping mechanism described above. The unconcentrated urine and dialysate within thethoracic pouch16 then pass through thesecond conduit36 and one-way valve38 therein to a section of the patient'sbowel18. Movement of the unconcentrated urine and dialysate from thethoracic pouch16 through thesecond conduit36 takes place by the internal body pumping mechanism described above. As mentioned above, thecentral region66 of thesecond conduit36, which directs the unconcentrated urine and dialysate into the segment of the patient'sbowel18 is formed of a semi-permeable membrane so as to allow the unconcentrated urine within theconduit36 to move into the bowel, wherein the bowel functions to reabsorb water, electrolytes and small molecules, resulting in concentrated urine. However, the semi-permeable membrane prevents the dialysate from leaving thesecond conduit36.
• In a manner similar to the prosthesis shown in FIG. 1, some of the concentrated urine in FIG. 2 will traverse the[0059]appendix22, which has a one-way peristalsis to thebladder20, which appropriately excretes the concentrated urine based on the bladder's normal function. The remaining urine (unconcentrated and partially concentrated) is returned with the dialysate through thedistal end46 of theconduit36 to theabdominal sac64 for circulating and recleansing. Preferably, thedistal end46 of theconduit36 is impermeable to preclude the escape of any urine and dialysate therefrom.
• Typically in chronic peritoneal dialysis, the dialysate is introduced directly into the peritoneal space via a catheter and removed after it has drawn in urine. Introducing the dialysate into the peritoneal space presents problem with the chronic peritoneal dialysis procedure. Peritoneal irritation and chronic thickening caused by the dialysis leads to poor diffusion and ultra filtration. In addition, the dialysate in the peritoneal space can cause problems in the bloodstream (e.g., hypertonic sugar, hypertonic salt, increases in nitrogenous wastes, and problems in the bloodstream including bleeding and clotting disorders, poisoning various enzyme systems, antigen-antibody reactions, D-C, etc.).[0060]
• The embodiments of the invention discussed above and illustrated in FIGS. 1 and 2 do not suffer from these problems because the dialysate cannot filter through the semi-permeable membrane. However, the embodiments of the invention discussed below allow for direct contact of the dialysate with the peritoneum. The continuous internal peritoneal dialysis prosthesis discussed below are of greater benefit when using a dialysate that cannot be absorbed by the lymphatic system or where there is minimal absorption of the dialysate without toxicity.[0061]
• Referring to FIG. 3, an exemplary continuous internal peritoneal dialysis prosthesis inserted within a patient's body is schematically illustrated at[0062]70. Theprosthesis70 includes anabdominal sac64 in the abdominal region of the patient below thediaphragm14, athoracic pouch16 in the thoracic region of the patient's body above thediaphragm14, a section of a patient'sbowel18 located within the abdominal region,conduits26 and36 connected between theabdominal sac64 and thethoracic pouch16, and asemi-permeable membrane72 enclosed within thebowel18. Theabdominal sac64,thoracic pouch16,bowel18, andconduits26 and36 are similar to the like elements shown in FIG. 2. However, theconduits26 and36 include a series of relatively large holes54 (e.g., one-half centimeter) that allow urine and dialysate to permeate therethrough, as will be described later.
• The[0063]abdominal sac64 may be similar to the abdominal sac12 shown in FIG. 1, but without thewall34. As with the abdominal sac12 of FIG. 1, portions of theabdominal sac64 may alternatively be formed of an impermeable or substantially impermeable membrane that is more elastic than the semi-permeable membrane and does not permit the dialysate to exit, even when the impermeable or substantially impermeable membrane is expanded beyond its elastic limit. Therefore, before the semi-permeable membrane expands under pressure to an extent that could permit dialysate to exit, the impermeable or substantially impermeable membrane stretches to contain the dialysate while inhibiting the dialysate from exiting therefrom.
• As can be seen in FIG. 3, the section of the patient's[0064]bowel18 is sutured to theconduit36 at both theentrance42 to thebowel18 and theexit44 from thebowel18. Thesemi-permeable membrane72 extends about thesecond conduit36 within thebowel18 and is attached to thesecond conduit36 at both theentrance74 to themembrane72 and theexit76 from themembrane72. Thesemi-permeable membrane72 is preferably a synthetic plastic material with some elastic qualities having a porosity which precludes dialysate from filtering through the semi-permeable membrane, but permits unconcentrated urine to filter through the material.
• In this embodiment, both the dialysate and unconcentrated urine are present in the peritoneal region. The[0065]abdominal sac64 receives unconcentrated urine and dialysate via the relativelylarge holes54 of thefirst conduit26. In addition, theabdominal sac64 receives unconcentrated urine through sections of the wall of theabdominal sac64 that are made of semi-permeable membrane.
• The unconcentrated urine and dialysate entering the[0066]abdominal sac64 is directed through thefirst conduit26 and the one-way valve28, through thediaphragm14 and into thethoracic pouch16 by the internal body pumping mechanism described above. Unconcentrated urine and dialysate also flow from the peritoneum through the relativelylarge holes54 into thefirst conduit26, and is directed toward thethoracic pouch16. The unconcentrated urine and dialysate within thethoracic pouch16 then pass through thesecond conduit36 and the one-way valve38 therein to a section of the patient'sbowel18. Movement of the unconcentrated urine and dialysate from thethoracic pouch16 through thesecond conduit36 takes place by the internal pumping mechanism described above, which may be assisted or supplemented with a pump. As noted above, thesecond conduit36 which directs the unconcentrated urine and dialysate into the segment of the patient'sbowel18 includes a series of relativelylarge holes54 so as to allow the unconcentrated urine and dialysate within thesecond conduit36 to flow out of theconduit36. Thesemi-permeable membrane72 that is within thebowel18 has a porosity which precludes the dialysate that filtered through theholes54 of thesecond conduit36 from escaping into thebowel18, but still permits the unconcentrated urine to permeate into thebowel18, wherein thebowel18 functions to reabsorb water, electrolytes and small molecules resulting in concentrated urine.
• As noted earlier, when the unconcentrated urine is turned into concentrated urine within the section of the patient's[0067]bowel18, most of the concentrated urine will exit to the distalright ureter24, which can be attached to the cecum orappendix22 when appropriate. The concentrated urine will then flow into theurinary bladder20 to be expelled intermittently, just as in a normally functioning human patient. The dialysate and returning urine is returned through thedistal end46 of theconduit36 to theabdominal sac64 for recirculation and recycling. Thisdistal end46 of theconduit36, and the sections of theconduits26 and36 above thediaphragm14 are impermeable to preclude the escape of any urine or dialysate therefrom.
• FIG. 4 is still another embodiment of the invention wherein dialysate is in direct contact with the peritoneum. Referring to FIG. 4, an exemplary continuous internal peritoneal dialysis prosthesis inserted within a patient's body is schematically illustrated at[0068]80 and is similar to the prosthesis is shown in FIG. 1. Theprosthesis80 includes anabdominal sac82 in the abdominal region of the patient belowdiaphragm14, athoracic pouch16 in the thoracic region of the patient's body above thediaphragm14, a section of the patient'sbowel18 located within the abdominal section of the patient and aurinary bladder20 connected to a downstream end of thebowel18 through the patient's cecum orappendix22 and distalright ureter24.
• The[0069]abdominal sac82 includes a semi-permeableouter wall56 and an impermeableouter wall58 separated by asemi-permeable window86. The region of theabdominal sac82 defined by the semi-permeableouter wall56 and thesemi-permeable window86 is adialysis sac84. The semi-permeableouter wall84 andwindow86 are formed of a semi-permeable membrane as discussed in detail above. Theabdominal sac82,dialysis sac84,thoracic pouch16,first conduit26,bowel18 andsecond conduit36 shown in FIG. 4 are substantially similar to the abdominal sac12,dialysis sac32,thoracic pouch16,first conduit26,bowel18 andsecond conduit36 shown in FIG. 1. However, instead of thedistal end46 of thesecond conduit36 being formed of an impermeable material and connected to the abdominal pouch12 (FIG. 1), thedistal end46 of FIG. 4 includes a series of relatively large holes54 (e.g., one-half centimeter) and is connected to the semi-permeableouter wall56 of thedialysis sac84.
• The[0070]distal end46 includes theholes54 so as to allow unconcentrated urine and dialysate in the peritoneum to move into theconduit36 and then into thedialysis sac84. The dialysate is contained within thedistal end46 of theconduit36 and thedialysis sac84 and does not flow through the remainder of theprosthesis80. The one-way valve48 permits the unconcentrated and partially concentrated urine exiting from thesecond conduit36 in thebowel18 to travel towards thedialysis sac84, but does not allow fluid, including the dialysate, to enter thesecond conduit36 in thebowel18 from thedistal end46.
• In FIG. 4, unconcentrated urine flows from the[0071]abdominal sac82 through thefirst conduit26 and one-way valve28 through thediaphragm14 to thethoracic pouch16. The unconcentrated urine within thethoracic pouch16 then passes through thediaphragm14 and one-way valve38 in the second conduit to the patient'sbowel18. Movement of the urine through theprosthesis10 takes place by the internal pumping mechanism described in detail above.
• As noted earlier during the discussion of FIG. 1, the[0072]second conduit36 of FIG. 4, which directs the unconcentrated urine into the segment of the patient'sbowel18, includes a series of relativelylarge holes54. Theholes54 allow the unconcentrated urine within theconduit36 to move into thebowel18, wherein thebowel18 functions to reabsorb water, electrolytes and small molecules resulting in concentrated urine. Some of the concentrated urine will traverse theappendix22 which has a one-way peristalsis to thebladder20, which appropriately excretes the concentrated urine based on the bladder's normal function. The remaining urine is returned through thedistal end46 of the conduit36 (where it is mixed with unconcentrated urine and dialysate from the peritoneum) to thedialysis sac84 for recirculation and recleansing.
• In order to prevent the[0073]dialysis sac84 from expanding to an extent that permits the dialysate to exit the walls, portions of the semi-permeableouter wall56 and thesemi-permeable window86 may alternatively be formed of an impermeable or substantially impermeable membrane that is more elastic than the semi-permeable membrane and does not permit the dialysate to exit, even when the impermeable or substantially impermeable membrane is expanded beyond its elastic limit. Therefore, before the semi-permeable membrane expands under pressure to an extent that could permit dialysate to exit, the impermeable or substantially impermeable membrane stretches to contain the dialysate while inhibiting the dialysate from exiting therefrom. Also, theimpermeable wall58 could be made elastic and thesemi-permeable wall56 andwindow86 made inelastic.
• Although the[0074]conduits26 and36 are illustrated in the exemplary embodiments shown in FIGS.1-4 as being separate conduits spaced apart from each other and extending through separate passages in thediaphragm14, it should be understood that, in a preferred construction, theconduits26 and36 are interconnected together and pass through only a single aperture in thediaphragm14. The spaced apart arrangement of theconduits26 and36 is shown in the drawings for purposes of clarity.
• The operation of all of the embodied prostheses shown in FIGS.[0075]1-4 is preferably continuous and relies upon the internal body pumping action of the disclosed systems. This internal body pumping action is described in relation to FIG. 1 and is substantially similar in operation for the other exemplary embodiments shown in FIGS.2-4 as a skilled artesian would readily understand. The described internal body pumping action is a variation of the internal body pump and systems disclosed in Applicant's U.S. Pat. No. 5,813,410, the entire subject matter of which is incorporated by reference herein. In addition, for all of the exemplary embodiments, the pumping action provided by the breathing cycle of the patient can be augmented, or even supplanted, by another device (e.g., a mechanical or electrical pump implanted in the person's body in fluid communication with the loop of circulating fluid).
• Referring to FIG. 5, a further and preferred exemplary continuous peritoneal dialysis prosthesis inserted within a person's body is schematically illustrated at[0076]100. Theprosthesis100 includes athoracic pouch16 in the thoracic region of the patient's body above thediaphragm14, a section of the patient'sbowel18 located within the abdominal region,conduits26 and36 communicating between thethoracic pouch16 and the abdominal region, and asemi-permeable membrane72 enclosed within thebowel18. Thethoracic pouch16,bowel18, andconduits26 and36 are similar to the like elements shown in FIG. 3. However, this embodiment is different than the embodiment shown in FIG. 3 because this embodiment omits the abdominal sac disclosed in FIG. 3.
• As can be seen in FIG. 5, the section of the patient's[0077]bowel18 is sutured to theconduit36 at both theentrance42 to thebowel18 and theexit44 from thebowel18. Thesemi-permeable membrane72 extends about thesecond conduit36 within thebowel18 and is attached to thesecond conduit36 at both theentrance74 to themembrane72 and theexit76 from themembrane72. Thesemi-permeable membrane72 is preferably a synthetic plastic material with some elastic qualities having a porosity which precludes dialysate from filtering through the semi-permeable membrane, but permits unconcentrated urine to filter through the material. Theconduits26 and36 include a series of relatively large holes54 (e.g., about one-half centimeter) that allow urine and dialysate to permeate therethrough as will described later.
• In this embodiment, both the dialysate and unconcentrated urine are present in the peritoneal region. The first conduit receives unconcentrated urine and dialysate via the relatively[0078]large holes54 and distal opening102. The unconcentrated urine and dialysate is directed through thefirst conduit26 and the one-way valve28, through thediaphragm14 and into thethoracic pouch16 by the internal body pumping mechanism described above. The unconcentrated urine and dialysate within thethoracic pouch16 then pass through thesecond conduit36 and the one-way valve38 therein to a section of the patient'sbowel18. Movement of the unconcentrated urine and dialysate from thethoracic pouch16 through thesecond conduit36 takes place by the internal pumping mechanism described above, which may be assisted or supplemented with a pump. In particular, thethoracic pump16 serves as a pump influenced by a patient's breathing pattern to cause the unconcentrated urine and dialysate to flow through theprosthesis100.
• The[0079]prosthesis100 omits the abdominal sac disclosed in the other embodiments of this invention and generally employs the peritoneal region as the “sac” region for retaining dialysate and unconcentrated urine. Accordingly, like the prosthesis shown above in FIGS. 3 and 4, theprosthesis100 is of greatest benefit when using a dialysate that cannot be absorbed by the lymphatic system or where there is minimal absorption of the dialysate without toxicity (e.g., absorbable albumin). Because the dialysate is not contained within a separate abdominal sac, it is preferred that dialysate is added to the prosthesis (e.g., about 1 liter every few days) to ensure that a sufficient amount of dialysate is retained within the peritoneal region.
• It should be apparent that the unconcentrated urine and dialysate does not flow through the[0080]prosthesis100 as efficiently as the fluids flow through the embodiments discussed above that include both an abdominal sac and a thoracic pouch. Without an abdominal sac, the prosthesis does not form a closed loop and the thoracic pouch is relied upon to cause the fluid to flow through the prosthesis without the aid of an abdominal sac, as described above. Accordingly, this embodiment may be better suited for a patient that has only partial kidney failure.
• As noted above, the[0081]second conduit36 which directs the unconcentrated urine and dialysate into a segment of the patient'sbowel18 includes a series of relativelylarge holes54 so as to allow the unconcentrated urine and dialysate within thesecond conduit36 to flow out of the conduit. Thesemi-permeable membrane72 that is within the bowel has a porosity which precludes the dialysate that filters through theholes54 of thesecond conduit36 from escaping into thebowel18, but still permits the unconcentrated urine to permeate into thebowel18, wherein the bowel functions to reabsorb water, electrolytes and small molecules resulting in concentrated urine.
• Still referring to FIG. 5, it should be noted that in lieu of the relatively[0082]large holes54 located in thesecond conduit36 and thesemi-permeable membrane72 located within thebowel18, theconduit36 within thebowel18 can be constructed like thecentral region66 of theconduit36 shown in FIG. 2. That is, in FIG. 5, theconduit36 within thebowel18 can be formed of the semi-permeable membrane.
• As noted earlier, when the unconcentrated urine is turned into concentrated urine within the section of the patient's[0083]bowel18, most of the concentrated urine will exit to the distalright ureter24 which can be attached to the cecum orappendix22 when appropriate. The concentrated urine will then flow into theurinary bladder20 to be expelled intermediately, just as in a normally functioning human person. The dialysate and returning urine is returned through thedistal end46 of theconduit36 into the abdominal region. Preferably, thedistal end46 of thesecond conduit36 should either be of a very small diameter, or employ a moderate pressure one-way valve48 therein to control the flow of fluid into the peritoneal space in a manner that allows adequate time for the bowel to absorb water from the unconcentrated urine passing therethrough, but not such as to prevent flow of unconcentrated or partially concentrated urine back into the peritoneal space for lymphatic reabsorption and recycling through the entire system.
• It should be noted that the[0084]thoracic pouch16 preferably communicates with asubcutaneous access reservoir50, which includes an access section closely adjacent the patient's skin. Thesubcutaneous access reservoir50 permits the monitoring and testing of the urine in order to determine the effectiveness of the prosthesis. Thereservoir50 also provides adjustments of urine flow and urine constituent by adding or subtracting dialysate to fit each patient's needs. The dialysate can be added or withdrawn from thesubcutaneous access reservoir50 using a syringe or tube inserted through the patient's skin into the reservoir.
• Referring to FIG. 6, there is shown at[0085]110 an exemplary internal peritoneal dialysis prosthesis inserted within a patient's body in accordance with yet still another preferred embodiment of this invention. As shown in FIG. 6, theprosthesis110 includes anabdominal sac112 in the abdominal region of the patient below the diaphragm. Theabdominal sac112 includes an extension that expands into a section of the patient'sbowel18.
• The[0086]abdominal sac112 may be similar to the abdominal sacs discussed above. For example, the abdominal sac is arranged for having a dialysate therein. Thissac112 is generally formed of a semi-permeable membrane having a porosity which precludes the dialysate within theabdominal sac112 from escaping into the peritoneal region but still permits unconcentrated urine within the peritoneal region to enter theabdominal sac112 through osmotic pressure. Because theabdominal sac112 is required to function in an aqueous environment, it preferably is formed of a synthetic plastic material with some elastic qualities (e.g., Gortex-like cloth). However, theabdominal sac112 should not be so elastic as to expand to an extent that permits the dialysate molecules or microstructures to exit from expanded pores of its walls.
• As with the abdominal sacs discussed above, portions of the wall of the[0087]abdominal sacs112 may alternatively be formed of an impermeable or substantially impermeable membrane that is more elastic than the semi-permeable membrane and does not permit the dialysate to exit, even when the impermeable or substantially impermeable membrane is expanded beyond its elastic limit. Therefore, before the semi-permeable membrane expands under pressure to an extent that could permit dialysate to exit, the impermeable or substantially impermeable membrane stretches to contain the dialysate while inhibiting the dialysate from exiting therefrom.
• Still referring to FIG. 6, a section of the patient's[0088]bowel18 is sutured to theabdominal sac112, thereby enclosing the extension114 of the sac in the bowel. This extension includes the semi-permeable membrane wall so as to allow the unconcentrated urine drawn into theabdominal sac112 by osmotic pressure to move into thebowel18, wherein the bowel functions to reabsorb water, electrolytes and small molecules, resulting in concentrated urine. However, the semi-permeable membrane wall prevents the dialysate from moving into the bowel, thus keeping the dialysate within theabdominal sac112.
• The[0089]abdominal sac112 preferably communicates with asubcutaneous access reservoir51, which includes an access section closely adjacent the patient's skin. The subcutaneous access reservoir (SAR)51 permits the monitoring and testing of the dialysate and urine in order to determine the effectiveness of the prosthesis. TheSAR51 provides adjustment of urine flow and urine constituents by adding or subtracting dialysate to fit each patient's needs. The dialysate can be added or withdrawn from theSAR51 using a syringe or tube inserted through the patient's skin into the reservoir.
• Unlike the other embodiments of the invention discussed above, the[0090]prosthesis110 does not include conduits for continuous mixing and circulation of unconcentrated urine and dialysate. In this regard, it should be noted that theprosthesis110 is likely not as efficient as the other preferred embodiments because thisprosthesis110 does not take advantage of a respiratory pump. Accordingly, this prosthesis is better suited for patients having a less severe renal failure. Another possible disadvantage of this embodiment is that theabdominal sac112 may be subject to layering and stagnation of dialysate and receive unconcentrated urine making the patient more susceptible to infection. In other words, the mixing and circulation provided by the prosthesis of the embodiments discussed above improves the efficiency of the dialysis and precludes layering and stagnation of fluids within the prosthesis. The possible layering and stagnation of the fluids may be minimized in this embodiment if the patient frequently moves or changes the angular orientation (e.g., vertical, horizontal) of their torso, to allow the fluids in theabdominal sac112 to flow influenced by gravitational pull. However, one advantage of this prosthesis over the embodiments described above, is that thisprosthesis110 uses fewer elements and is more simple in its operation. Thisprosthesis110 also creates less strain on the patient during surgery to implant the prosthesis than the prosthesis of other preferred embodiments since fewer elements are inserted into the body.
• Referring to FIG. 7, there is shown at[0091]120, an exemplary continuous internal peritoneal dialysis prosthesis inserted within a patient's body in accordance with yet another preferred embodiment of this invention. Theprosthesis120 is similar to the prosthesis discussed above in FIGS.1-6, and particularly in FIGS.1-4. As shown in FIG. 7, theprosthesis120 includes anabdominal sac64 in the abdominal region of the patient belowdiaphragm14, athoracic pouch16 in the thoracic region of the patient's body above thediaphragm14, first andsecond conduits26,36 arranged for communicating fluid between theabdominal sac64 and thethoracic pouch16, and a section of the patient'sbowel18 located within the abdominal section of the patient. The patient'surinary bladder20 is connected to a downstream end of thebowel18 preferably via the patient's distalright ureter24 and the patient's cecum orappendix22.
• The[0092]abdominal sac64 is connected to thethoracic pouch16 through theconduit26, which preferably includes a one-way valve28 therein. The one-way valve28 permits fluid to flow only in the direction ofarrow30 from theabdominal sac64 into thethoracic pouch16.
• The[0093]second conduit36 is connected to thethoracic pouch16 through aproximate end122 and passes through thediaphragm14 into and through the section of the patient'sbowel18, which has been separated from the digestive system (or GI tract) of the patient. While not being limited to a particular theory, thesecond conduit36 includes a one-way valve38 near itsproximal end122 to permit fluid (e.g. dialysate and urine) to flow from thethorascic pouch16 through the section of the patient'sbowel18 only in the direction ofarrow40.
• As can best be seen in FIG. 7, the[0094]second conduit36 has a Y-shaped tubing that bifurcates into twoconduit sections124 and126.First conduit section124 includes adistal opening130, and extends from thesecond conduit36 into afirst segment128 of thebowel18 until it ends at thedistal opening130. Thesecond conduit section126 extends through asecond segment132 of thebowel18 and has adistal end134 connected to theabdominal sac64 to recycle the flow of dialysate (and possibly some urine) back into theabdominal sac64, as will be described in greater detail below. While not being limited to a particular theory, thesecond conduit section126 is provided with a one-way valve48 at itsdistal end134 to permit the fluid (e.g., dialysate and urine) to flow only in the direction ofarrow49 from the patient'sbowel18 to theabdominal sac64.
• The[0095]first bowel segment128 is sutured to thefirst conduit section124 at theentrance42 to the first bowel segment. Thesecond bowel segment132 is sutured to thesecond conduit section126 at anentrance136 to the second bowel segment and at anexit44 from thebowel18.
• The[0096]conduit sections124,126 haveapertures54 that are arranged to communicate within thebowel segments128,132 so as to allow the unconcentrated urine and dialysate within thesecond conduit36 to move into thebowel18. Thebowel18 functions to reabsorb water, electrolytes and small molecules, resulting in the formation of concentrated urine. As noted above, the section ofbowel18 is isolated from the rest of the bowel, and therefore from the Gastrointestinal (GI) tract. While not being limited to a particular theory, the section ofbowel18 that is selected preferably includes the right colon as thefirst bowel segment128 and the ileum as thesecond bowel segment132. As noted above, the section ofbowel18 is capable of about 90% water reabsorption which translates to 10 to 20 liters of water per day.
• Still referring to FIG. 7, a[0097]filter138 is positioned at alower end140 of the section ofbowel18. Thefilter138 is a semi-permeable membrane that allows urine to pass through but blocks the dialysate from filtering through the membrane. While not being limited to a particular theory, thefilter138 is preferably disk-shaped and supported at its periphery by a plastic frame. Thefilter138 is preferably held in place in the section ofbowel18 with an elastic member (e.g., rubber band) wrapped around thelower section140 of thebowel18 and the plastic frame. If desired, the plastic frame may include a groove or notch around its frame to assist in holding thefilter138 and elastic member in position within thebowel18.
• The[0098]filter138 functions similarly to thesemi-permeable membrane72 discussed above and shown in FIG. 3. As such, thesemi-permeable membrane filter138 is preferably a synthetic plastic material with some elastic quality having a porosity which precludes dialysate from filtering through the semi-permeable membrane, but permits urine to filter through the material. Thefilter138 provides an alternate approach to the structure shown in FIG. 3 for filtering urine, but not dialysate, to theappendix22, which has a one-way peristalysis to thebladder20. As in the other embodiments, thebladder20 appropriately excretes the concentrated urine based on the bladder's normal function.
• Referring to FIG. 7, the urine remaining in the section of[0099]bowel18 that is not filtered through thesemi-permeable filter138 is returned through thedistal end134 of thesecond conduit section126 to theabdominal sac64 for recirculation. While not being limited to a particular theory, thedistal end134 of thesecond conduit section126 is preferably impermeable to preclude the escape of any urine therefrom.
• The second conduit, its extension (the first conduit section[0100]124), and thefilter138 form afluid guide member142 that is adapted to transfer unconcentrated urine from thethoracic pouch16 via the second conduit into the separate section ofbowel18, and to transfer dialysate from the thoracic pouch to theabdominal sac64.
• As noted above, the[0101]prosthesis120 shown in FIG. 7 is constructed similarly to the various prostheses discussed above. In this embodiment, the dialysate is not contained within a dialysis sac. While not being limited to a particular theory, theabdominal sac64 preferably does not include or share a window with a dialysis sac, as shown, for example, in FIGS. 1 and 4. In FIG. 7, theabdominal sac64,thoracic pouch16,conduits26,36 and the section ofbowel18 provide a closed system for the dialysate, allowing the dialysate to cycle within theprosthesis120, but preventing the dialysate from leaving theprosthesis120.
• As discussed above, the[0102]abdominal sac64 is generally formed of a semi-permeable membrane having a porosity which precludes the dialysate within theabdominal sac64 from escaping into the peritoneal region, but still permits unconcentrated urine within the peritoneal region to enter theabdominal sac64 through osmotic pressure. Because theabdominal sac64 is required to function in an aqueous environment, it preferably is formed of a synthetic plastic material with some elastic qualities (e.g., gortex-like cloth). However, theabdominal sac64 should not be so elastic as to expand to an extent that permits the dialysate molecules or microstructures to exit from expanded pores of its walls.
• As with the abdominal sacs discussed above, portions of the wall of the[0103]abdominal sac64 may be formed of an impermeable or a substantially impermeable membrane that is more elastic than the semi-permeable membrane and does not permit the dialysate to exit, even when the impermeable or substantially impermeable membrane is expanded beyond its elastic limit. Therefore, before the semi-permeable membrane expands under pressure to an extent that could permit dialysate to exit, the impermeable or substantially impermeable membrane stretches to contain the dialysate while inhibiting the dialysate from exiting therefrom.
• The unconcentrated urine and dialysate entering the[0104]abdominal sac64 is directed through thefirst conduit26 and the one-way valve28 through thediaphragm14 and into thethoracic pouch16 by the internal body pumping mechanism described above. The unconcentrated urine and dialysate within thethoracic pouch16 then pass through the Y-shapedsecond conduit36 and the one-way valve38 therein. The unconcentrated urine and dialysate are then directed through the twoconduit sections124,126 to a respective one of thebowel segments128,132. Movement of the urine and dialysate from thethoracic pouch16 through the second conduit takes place by the internal body mechanism described above, which may be assisted or supplemented with a pump.
• The[0105]conduit sections124,126 of thesecond conduit36, which direct the urine and dialysate into the section of the patient'sbowel18, include a series ofapertures54 so as to allow the urine and dialysate within theconduit sections128,132 to flow out of theconduit36. Thesemi-permeable filter138 that is within thebowel18 has a porosity which precludes the dialysate that filtered through theholes54 of thesecond conduit36 from escaping from thebowel18 into theappendix22, distalright ureter24, orbladder20, but still permits the urine, now concentrated, to permeate through thebowel18.
• As noted above, when the unconcentrated urine is turned into concentrated urine within the separated section of the patient's[0106]bowel18, most of the concentrated urine will filter through thesemi-permeable filter138 and exit thebowel18. The concentrated urine will then flow into theurinary bladder20 to be expelled intermediately, just as in a normally functioning human patient. The dialysate and returning urine is returned through thedistal end134 of the second conduit'ssecond section126 to theabdominal sac64 for recirculation.
• Referring to FIG. 8 there is shown at[0107]150, an exemplary continuous internal peritoneal dialysis prosthesis inserted within a patient's body in accordance with yet still another preferred embodiment of the invention, which is similar to theprostheses10,62,70,80 and120 discussed above. As shown in FIG. 8, theprosthesis150 includes anabdominal sac64 in the abdominal region of the patient belowdiaphragm14, athoracic pouch16 in the thoracic region of the patient's body above thediaphragm14, a section of the patient'sbowel18 located within the abdominal section of the patient, and the patient'surinary bladder20 connected to a downstream end of thebowel18 through the patient's cecum orappendix22 and a distalright ureter24. As described above in the other embodiments, theabdominal sac64 is connected to thethoracic pouch16 through aconduit26, including a one-way valve28 therein. The one-way valve28 permits fluid to flow only in the direction ofarrow30 from theabdominal sac64 into thethoracic pouch16.
• The[0108]prosthesis150 includes asecond conduit36 having aproximal end152 connected to thethoracic pouch16, and adistal end154 connected to theabdominal sac64. While not being limited to a particular theory, thesecond conduit36 passes through thediaphragm14 and preferably includes a one-way valve38 near itsproximal end152 to permit fluid (e.g., dialysate and unconcentrated urine) to flow from thethoracic pouch16 into the peritoneal region only in the direction ofarrow40.
• The[0109]second conduit36 of FIG. 8 includes aurine transfer sac156 arranged to transfer unconcentrated urine to an extension of the second conduit, hereinafter referred to as athird conduit158. Thethird conduit158 includes aurine receiving sac160 arranged to receive unconcentrated urine from theurine transfer sac156 and to transfer the urine to the separated section ofbowel18. To transfer unconcentrated urine from thesecond conduit36 to thebowel18, thethird conduit158 extends through and terminates in the section ofbowel18. Thesecond conduit36, its extension (the third conduit158) and thesemi-permeable membrane window166 form afluid guide member182 that is adapted to transfer unconcentrated urine from thethoracic pouch16 via the second and third conduits into the separated section of the patient'sbowel18, and to transfer dialysate from thethoracic pouch16 via the second conduit to theabdominal sac64.
• The[0110]urine transfer sac156 includes an impermeableouter wall162, and theurine receiving sac160 includes an impermeableouter wall164 coupled to the impermeableouter wall162. Theurine transfer sac156 andurine receiving sac160 are separated by asemi-permeable membrane window166 having pores or apertures that provide the window with a porosity which precludes dialysate within theurine transfer sac156 from escaping into theurine receiving sac160, but permits urine within theurine transfer sac156 to enter theurine receiving sac160. Therefore, in this example of the preferred embodiment, the dialysate is precluded from entry into the section ofbowel18. Instead, the dialysate continues within alower section168 of thesecond conduit36 toward thedistal end154. Thedistal end154 is provided with a one-way valve48 to permit the fluid (e.g., dialysate and possibly some urine) to flow only in the direction ofarrow49 from thesecond conduit36 into theabdominal sac64.
• As can be seen in FIG. 8, the[0111]third conduit158 includes a one-way valve170 arranged to permit fluid, such as unconcentrated urine, to flow only in the direction ofarrow172 from theurine receiving sac160 towardapertures54 located downstream from the one-way valve170. As noted above, thethird conduit158 directs unconcentrated urine from thesecond conduit36, and in particular, theurine transfer sac156, to the section ofbowel18, where the unconcentrated urine is turned into concentrated urine and eventually exits via theurinary bladder20 intermittently, just as in a normally functioning human patient.
• While not being limited to a particular theory, the[0112]third conduit158 has a Y-shaped tubing that bifurcates into afirst leg174 and asecond leg176 downstream from the one-way valve170. Thefirst leg174 extends into and terminates within thefirst bowel segment128. Thesecond leg176 extends into and terminates within in thesecond bowel segment132. As can be seen in FIG. 8, thefirst bowel segment128 is sutured to thefirst leg174 of thethird conduit158 at theentrance178 to the first bowel segment. Thesecond bowel segment132 is sutured to thesecond leg176 at theentrance180 to the second bowel segment. The first andsecond legs174,176, which direct the unconcentrated urine into the section of the patient'sbowel18, both include a series ofapertures54 large enough to allow the unconcentrated urine within thethird conduit158 to move out of the conduit and into thebowel18 wherein the section of bowel functions to reabsorb water, electrolytes, and small molecules, resulting in the formation of concentrated urine.
• As noted above, the section of the[0113]bowel18 that preferably is selected includes the right colon and ileum, and is capable of 90 percent water reabsorption in the bowel, which translates to 10 to 20 liters of water per day. Also as noted above, the jejunum is anastomosed to the traverse colon to restore the integrity of the GI tract, and therefor, although the section of patient'sbowel18 is isolated from the GI tract, its blood supply remains intact so as to permit it to function in this invention.
• As discussed above, the[0114]abdominal sac64 is generally formed of a semi-permeable membrane having a porosity which precludes the dialysate within theabdominal sac64 from escaping into the peritoneal region, but still permits unconcentrated urine within the peritoneal region to enter theabdominal sac64 through osmotic pressure. Theabdominal sac64 is preferably formed of a synthetic plastic material with some elastic qualities. However, the abdominal sac should not be so elastic as to expand to an extent that permits the dialysate molecules or microstructures to exit from expanded pores of its walls.
• As with the[0115]abdominal sac64 discussed in other embodiments of this invention, portions of the wall of theabdominal sac64 may alternatively be formed of an impermeable or a substantially impermeable membrane that is more elastic than the semi-permeable membrane and does not permit the dialysate to exit, even when the impermeable or substantially impermeable membrane is expanded beyond its elastic limit. Therefore, before the semi-permeable membrane expands under pressure to an extent that could permit dialysate to exit, the impermeable or substantially impermeable membrane stretches to contain the dialysate while inhibiting the dialysate from exiting therefrom.
• Still referring to FIG. 8, the unconcentrated urine entering the[0116]abdominal sac64 through the semi-permeable membrane, and the dialysate are directed through thefirst conduit26 and the one-way valve28, through thediaphragm14 and into thethoracic pouch16 by the internal body pumping mechanism described above. The unconcentrated urine and dialysate within thethoracic pouch16 then pass through thesecond conduit36 and the one-way valve38 therein to theurine transfer sac156. As noted above, thesemi-permeable membrane window166 precludes dialysate from filtering through the window, but allows the urine to pass through and into theurine receiving sac160. The dialysate is returned, possibly with some urine, through thelower section168 of thesecond conduit36 to theabdominal sac64 for circulating and recycling. Preferably, thelower section168 of thesecond conduit36 is impermeable to preclude the escape of any urine and dialysate therefrom.
• The unconcentrated urine that filters through the[0117]semi-permeable membrane window166 passes through the one-way valve170 into thebowel18, wherein thebowel18 functions to reabsorb water, electrolytes and small molecules resulting in concentrated urine. The concentrated urine exits to theurinary bladder20, preferably via the distalright ureter24 which can be attached to the cecum orappendix22 when appropriate. The concentrated urine is expelled intermittently from the bladder, just as in a normally functioning human patient.
• It should be noted that while the[0118]apertures54 have been described in FIG. 1 as being relatively large (e.g., 0.5 cm), the size of the apertures should not be limited to relatively large holes for this embodiment, as the size of the holes only need to be large enough to allow unconcentrated urine to pass from the third conduit into thebowel18. Theapertures54 are shown in FIG. 8 by way of example, and should not limit the scope of the invention to apertures of any particular size, as long as the apertures allow urine to flow through.
• While not being limited to a particular theory, it should be noted that the diameter of the[0119]lower section168 of thesecond conduit36 may be smaller than the diameter of the third conduit to augment the filtering of the unconcentrated urine through thesemi-permeable membrane window166 by creating an environment of higher pressure in theurine transfer sac156 than in theurine receiving sac160. It is readily understood that such a pressure differentiation between the interiors of the sacs may increase the transfer rate of the unconcentrated urine through thesemi-permeable membrane window166.
• Furthermore, as noted above, the pumping action provided by the breathing cycle of the patient can be augmented, or even supplanted, by another device (e.g., a mechanical or electrical watertight pump) implanted in the person's body in fluid communication with the loop of circulating fluid. Such a pump could be positioned anywhere along the first or second conduits in any of the embodiments, as readily understood by a skilled artisan. If supplanting or augmenting the pumping action provided via the thoracic pouch, the mechanical or electrical pump would preferably be attached to the first or second conduit between the abdominal sac and the section of[0120]bowel18. The mechanical or electrical pump could be connected by wire to a subcutaneous power source (e.g., a battery) in a location where it could be periodically replaced if necessary or desired.
• Referring to FIG. 9, there is shown at[0121]184, an exemplaryfluid guide member184 that is similar to thefluid guide member182 shown in FIG. 8. Like thefluid guide member182, thefluid guide member184 shown in FIG. 9 is adapted to transfer unconcentrated urine from a thoracic pouch via thesecond conduit36 andthird conduit158 into the separated section of the patient'sbowel18, and to transfer dialysate from the thoracic pouch via thesecond conduit36 to an abdominal sac.
• As best seen in FIG. 9, the[0122]fluid guide member184 includes asafety outlet186. Theoutlet186 is a pressure relief member arranged to communicate fluid from thesecond conduit36 to the section ofbowel18 if the pressure in the prosthesis becomes greater than desired. While not being limited to a particular theory, thesafety outlet186 preferably includes aconduit188 with a pressure sensitive one-way valve190 therein. Theconduit188 preferably is attached to theurine transfer sac156 and is sutured to the section ofbowel18 at anopening194.
• It is understood that the[0123]conduit188 could alternatively attach from another member of theprosthesis150, such as theabdominal sac64,first conduit26,thoracic pouch16 orsecond conduit36 to the section ofbowel18 for removing excess dialysate from the prosthesis to thebowel18 and eventually out of the patient's body. It is noteworthy that such a pressure relief member communicates dialysate from a part of the prosthesis arranged to contain dialysate to a part of the prosthesis below or after a semi-permeable membrane member, such as thewindow166, that filters urine through while precluding dialysate from filtering through. As shown in FIG. 9, this communication is preferably between theurine transfer sac156 and the section ofbowel18.
• Typically, the pressure in the prosthesis may become greater than desired if too much dialysate is present in the prosthesis. As discussed above, dialysate pulls unconcentrated urine into the prosthesis. If more dialysate is present in the prosthesis than desired, the dialysate may pull so much unconcentrated urine into the prosthesis that the[0124]abdominal sac64 andthoracic pouch16 become too full to operate efficiently as an internal body pump. Moreover, too much dialysate and unconcentrated urine in the prosthesis could possibly cause thesac156 to expand beyond its elastic limit, or cause damage to thesemi-permeable membrane window166. Accordingly, thefluid guide member184 includes thesafety outlet186 to direct dialysate and unconcentrated urine from theurine transfer sac156 to the section ofbowel18 when the pressure in thesac156 becomes greater than desired.
• The pressure sensitive one-[0125]way valve190 permits fluid to flow only in the direction ofarrow192 from theurine transfer sac156 to the section ofbowel18 when the pressure at thevalve190 becomes greater than a desired threshold. The desired threshold is preferably set above normal and allowable heightened pressure levels in theurine transfer sac156, and below a pressure level where damage to thesac156 orsemi-permeable membrane window166 may occur. For example, a desired threshold may be two to three times the normal operating pressure in the prosthesis.
• The[0126]safety outlet186 relieves pressure on theurine transfer sac156 andwindow166 by directing dialysate and unconcentrated urine from thesac156 directly to the section ofbowel18. This transfer of fluids occurs when the pressure is high enough to open the pressuresensitive valve190. Under normal circumstances, when the amount of pressure on theurine transfer sac156 andsemi-permeable membrane window166 is in a desired operating range, there is no need for thevalve192 to open. The pressuresensitive valve192 only opens when the pressure is above a desired range, such as, when too much dialysate is in the prosthesis, to allow thesafety outlet186 to direct dialysate and unconcentrated urine to the section ofbowel18, and thus, remove dialysate from the prosthesis. The removed dialysis escapes from thebowel18 into theappendix22 and eventually exits the patient via theurinary bladder20 as discussed above.
• Referring to FIG. 10 there is shown at[0127]200, an exemplary continuous internal peritoneal dialysis prosthesis inserted within a patient's body in accordance with another preferred embodiment of the invention, which is similar to theprostheses10,62,70,80,120 and150 discussed above. As shown in FIG. 10, theprosthesis200 includes anabdominal sac202 in the abdominal region of the patient belowdiaphragm14, athoracic pouch204 in the thoracic region of the patient's body above thediaphragm14, a section of the patient'sbowel18 located within the abdominal section of the patient, the patient'surinary bladder20 connected to a downstream end of thebowel18 through the patient's cecum orappendix22 and a distalright ureter24.
• The[0128]prosthesis200 includes or is substantially similar to many features shown in theprosthesis70 shown in FIG. 3, and in theprosthesis150 shown in FIG. 8. For example, in addition to the features listed above, theprosthesis200 includes afourth conduit206, asemi-permeable membrane72,apertures54 and oneway valves212,220 substantially similar to thesecond conduit36,semi-permeable membrane72,apertures54 and oneway valves38,48 shown in FIG. 3. Further, theprosthesis200 includes asecond conduit36, athird conduit158, aurine transfer sac156, aurine receiving sac160, asemi-permeable membrane window166, one-way valves38,48,170,apertures54, afirst segment128 of thebowel18 and asecond segment132 of the bowel substantially similar to the like numbered element shown in FIG. 8.
• The[0129]abdominal sac202 is substantially the same as previously describedabdominal sac64. As can best be seen in FIG. 10, theabdominal sac202 is connected to thethoracic pouch204 through aconduit26, including a one-way valve28 therein. The one-way valve28 permits fluid to flow only in the direction ofarrow30 from theabdominal sac202 into thethoracic pouch16. Theabdominal sac202 is also connected to thesecond conduit36 and thefourth conduit206 for receiving dialysate and some urine, as will be described below in greater detail.
• The[0130]abdominal sac202 is generally formed of a semi-permeable membrane having a porosity which precludes the dialysate within theabdominal sac202 from escaping into the peritoneal region, but still permits unconcentrated urine (e.g., ultrafiltrate of blood) within the peritoneal region to enter theabdominal sac202 through osmotic pressure. Theabdominal sac202 is preferably formed of a synthetic plastic material with some elastic qualities. However, the abdominal sac should not be so elastic as to expand to an extent that permits the dialysate molecules or microstructures to exit from expanded pores of its walls.
• As with the abdominal sacs discussed in other embodiments of this invention, portions of the wall of the[0131]abdominal sac202 may alternatively be formed of an impermeable or a substantially impermeable membrane that is more elastic than the semi-permeable membrane and does not permit the dialysate to exit, even when the impermeable or substantially impermeable membrane is expanded beyond its elastic limit. Therefore, before the semi-permeable membrane expands under pressure to an extent that could permit dialysate to exit, the impermeable or substantially impermeable membrane stretches to contain the dialysate while inhibiting the dialysate from exiting therefrom.
• The[0132]prosthesis200 includes asecond conduit36 having aproximal end152 connected to thethoracic pouch204, and adistal end154 connected to theabdominal sac202. While not being limited to a particular theory, thesecond conduit36 passes through thediaphragm14 and preferably includes a one-way valve38 near itsproximal end152 to permit fluid (e.g., dialysate and unconcentrated urine) to flow from thethoracic pouch204 into the peritoneal region only in the direction ofarrow40.
• The[0133]second conduit36 of FIG. 10 includes aurine transfer sac156 arranged to transfer unconcentrated urine to an extension of the second conduit, hereinafter referred to as athird conduit158. Thethird conduit158 includes aurine receiving sac160 arranged to receive unconcentrated urine from theurine transfer sac156 and to transfer the urine to the separated section ofbowel18. To transfer unconcentrated urine from thesecond conduit36 to thebowel18, thethird conduit158 includes adistal opening130, and extends from thesecond conduit36 into thefirst segment128 of thebowel18 until it ends at the distal opening. Thefirst bowel segment128 is sutured to thethird conduit158 at theentrance178 to the first bowel segment.
• As described above in reference to FIG. 8, the[0134]urine transfer sac156 shown in FIG. 10 includes an impermeableouter wall162, and theurine receiving sac160 includes an impermeableouter wall164 coupled to the impermeableouter wall162. Theurine transfer sac156 andurine receiving sac160 are separated by asemi-permeable membrane window166 having pores or apertures that provide the window with a porosity which precludes dialysate within theurine transfer sac156 from escaping into theurine receiving sac160, but permits urine within theurine transfer sac156 to enter theurine receiving sac160. While not being limited to a particular theory, the dialysate is precluded from entry into the section ofbowel18. Instead, the dialysate continues within alower section168 of thesecond conduit36 toward thedistal end154. Thedistal end154 is provided with a one-way valve48 to permit the fluid (e.g., dialysate and possibly some urine) to flow only in the direction ofarrow49 from thesecond conduit36 into theabdominal sac202. Preferably, thelower section168 of thesecond conduit36 is impermeable to preclude the escape of any urine and dialysate therefrom.
• As can be seen in FIG. 10, the[0135]third conduit158 includes a one-way valve170 arranged to permit fluid, such as unconcentrated urine, to flow only in the direction ofarrow172 from theurine receiving sac160 towardapertures54 located downstream from the one-way valve170. As noted above, thethird conduit158 directs unconcentrated urine from thesecond conduit36, and in particular, theurine transfer sac156, to the section ofbowel18, where the unconcentrated urine is turned into concentrated urine and eventually exits via theurinary bladder20 intermittently, just as in a normally functioning human patient.
• The[0136]fourth conduit206 has aproximal end208 connected to thethoracic pouch204, and adistal end210 connected to theabdominal sac202. Like the above discussedconduits26,36, and158, thefourth conduit206 is preferably made from silicon plastic, which is inert and does not cause peritoneal irritation. While not being limited to a particular theory, thefourth conduit206 passes through thediaphragm14 and preferably includes a one-way valve212 near itsproximal end152 to permit fluid (e.g., dialysate and unconcentrated urine) to flow from thethoracic pouch204 into the peritoneal region andbowel18 only in the direction ofarrow214. Thethoracic pouch204 is substantially similar to thethoracic pouch16 described in the preferred embodiments above. Further to thethoracic pouch16 described above, thethoracic pouch204 includes an additional port connected to thefourth conduit206 for permitting fluid to flow from thethoracic pouch204 into the fourth conduit.
• Still referring to FIG. 10, the patient's[0137]bowel18 includes end sections sutured to thefourth conduit206 at both anentrance216 to thesecond segment132 ofbowel18 and anexit218 from thebowel18. Thedistal end210 of thefourth conduit206 extends through a lower end of thebowel18 and is connected to theabdominal sac202 to recycle the flow of dialysate and urine back into the abdominal sac. Thedistal end210 is provided with a one-way valve220 to permit the urine to flow only in the direction ofarrow222 from the patient'sbowel18 to theabdominal sac202.
• The[0138]fourth conduit206 is substantially similar to thesecond conduit36 shown in FIG. 3. For example, thefourth conduit206 includes a series of relativelylarge holes54 that allow urine and dialysate to permeate from the conduit into thesemi-permeable membrane72. Thesemi-permeable membrane72 extends about thefourth conduit206 within thebowel18 and is attached to the fourth conduit at both anentrance74 to themembrane72 and theexit76 from themembrane72. Thesemi-permeable membrane72 is preferably a synthetic plastic material with some elastic qualities having a porosity which precludes dialysate from filtering through the semi-permeable membrane, but permits unconcentrated urine to filter through the material into thebowel18, wherein thebowel18 functions to reabsorb water, electrolytes and small molecules resulting in concentrated urine.
• A[0139]fluid guide member228 includes the conduits and filters that are adapted to transfer unconcentrated urine form thethoracic pouch204 into the separated section ofbowel18, and to transfer dialysate from the thoracic pouch to theabdominal sac202. Referring to FIG. 10, thefluid guide member228 includes the second, third, andfourth conduits36,158,206, thesemi-permeable membrane window166, thesemi-permeable membrane72, and the one-way valves located in the conduits.
• As noted above, the section of the[0140]bowel18 that preferably is selected includes the right colon or cecum and the ileum. The section ofbowel18 is capable of 90 percent water reabsorption, which translates to 10 to 20 liters of water per day. Referring to FIGS. 7, 8 and10, thefirst bowel segment128 is preferably the right (ascending) colon and thesecond bowel segment132 is preferably the ileum. Also as noted above, the jejunum is anastomosed to the traverse colon to restore the integrity of the GI tract, and therefor, although the section of patient'sbowel18 is isolated from the GI tract, its blood supply (e.g., arterial and venous) remains intact so as to permit it to function in this invention.
• As also noted above, the pumping action provided by the breathing cycle of the patient can be augmented, or even supplanted, by another device (e.g., a mechanical or electrical watertight rate adjustable pump) implanted in the person's body in fluid communication with the loop of circulating fluid. Such an adjustable pump for circulating fluid within the[0141]prosthesis200 is shown at224 along thefirst conduit26. The mechanical orelectrical pump224 shown in FIG. 10 preferably includes a battery that provides power to the pump for moving fluid in thefirst conduit26 from theabdominal sac202 to thethoracic pouch204 in the direction of thearrow226. As an alternative, thepump224 could be connected by a wire to a subcutaneous power source (e.g., a battery) in a location where it could be periodically replaced if necessary or desired as understood by a skilled artisan.
• In operation, the unconcentrated urine entering the[0142]abdominal sac202 through the semi-permeable membrane and the dialysate are directed through thefirst conduit26 and the one-way valve28, through thediaphragm14 and into thethoracic pouch204 by the internal body pumping mechanism, and if desired, by thepump224 described above. Unconcentrated urine and dialysate within thethoracic pouch204 pass through thesecond conduit36 and the one-way valve38 therein to theurine transfer sac156. As noted above, thesemi-permeable window166 precludes dialysate from filtering through the window, but allows the urine to pass through and into theurine receiving sac160. The dialysate is returned, possibly with some urine, through thelower section168 of thesecond conduit36 to theabdominal sac202 for recirculating and recycling.
• Unconcentrated urine and dialysate within the[0143]thoracic pouch204 also pass through thefourth conduit206 and the one-way valve212 therein to thesecond segment132 of the patient'sbowel18. Movement of the unconcentrated urine and dialysate from thethoracic pouch204 through thefourth conduit206 takes place by the internal pumping mechanism described above, which may be assisted or supplemented with thepump224. Thefourth conduit206 includes a series of relativelylarge holes54 so as to allow the unconcentrated urine and dialysate within the fourth conduit to flow out of the conduit within thesemi-permeable membrane72. Thesemi-permeable membrane72, which is within thebowel18 has a porosity which precludes the dialysate that filtered through theholes54 of thesecond conduit36 from escaping into thebowel18, but still permits the unconcentrated urine to permeate. The dialysate is returned, possibly with some urine, through thefourth conduit206 to theabdominal sac202 for recirculating and recycling.
• The unconcentrated urine that filters through the[0144]semi-permeable membrane window166 passes through the one-way valve170 andapertures54 into thebowel18. The unconcentrated urine that permeates through thesemi-permeable membrane72 passes into thebowel18. Thebowel18 functions to reabsorb water, electrolytes and small molecules resulting in concentrated urine. The concentrated urine exits to theurinary bladder20, preferably via the distalright ureter24 which can be attached to the cecum orappendix22 when appropriate. The concentrated urine is expelled intermittently from the bladder, just as in a normally functioning human patient.
• It should be noted that the[0145]apertures54 have been described in FIG. 1 as being relatively large (e.g., 0.5 cm). The size of theapertures54 should not be limited to relatively large holes for this embodiment, as the size of the apertures only need to be large enough to allow unconcentrated urine to pass from the third and fourth conduits into thebowel18. Theapertures54 are shown in FIG. 10 by way of example, and should not limit the scope of the invention to apertures of any particular size, as long as the apertures allow urine to flow through.
• While not being limited to a particular theory, it should be noted that the diameter of the[0146]lower section168 of thesecond conduit36 may be smaller than the diameter of thethird conduit158 to augment the filtering of the unconcentrated urine through thesemi-permeable window166 by creating an environment of higher pressure in theurine transfer sac156 than in theurine receiving sac160. It is readily understood that such a pressure differentiation between the interiors of the sacs may increase the transfer rate of the unconcentrated urine through thesemi-permeable window166.
• As an alternative embodiment to the embodiment shown by example in FIG. 10, it is understood that the[0147]second conduit36 andfourth conduit206 could be merged at either or both of their proximal or distal ends, before the merged conduit attaches to one of thethoracic pouch204 or theabdominal sac202. For example, instead of attaching both the second and fourth conduits to thethoracic pouch204, thefourth conduit206 could be attached to thesecond conduit36, preferably below the one-way valve38. An advantage of this alternative embodiment is that the one-way valve38 permits fluid to flow from thethoracic pouch204 to both the second and fourth conduits, rendering the one-way valve212 previously in thefourth conduit206 unnecessary. This arrangement also provides the benefit that thethoracic pouch204 does not attach directly to thefourth conduit206 and thus does not require an attachment port for the fourth conduit. Further, thefourth conduit206 does not pass through thediaphragm14. This arrangement ofthoracic pouch204 andconduits36,206 closely resembles thethoracic pouch16 andsecond conduit36 shown in FIG. 7, with the second conduit bifurcating intoconduit sections124 and126.
• As another example of an alternative embodiment to the embodiment shown by example in FIG. 10, instead of attaching both the[0148]distal end154 of thesecond conduit36 and thedistal end210 of thefourth conduit206 to theabdominal sac202, the distal end of the fourth conduit could be attached to the distal end of the second conduit, preferably before the one-way valve48. An advantage of this alternative embodiment is that the one-way valve48 permits fluid to flow from both the second and fourth conduits to theabdominal sac202, rendering the one-way valve220 previously in the fourth conduit unnecessary. This arrangement also provides the benefit that theabdominal sac202 does not attach directly to thefourth conduit206 and thus does not require an attachment port for the fourth conduit. In this arrangement, theabdominal sac202 is substantially identical to theabdominal sac64 described above.
• The examples of the alternative embodiments to the embodiment shown in FIG. 10 attach the[0149]fourth conduit206 to thesecond conduit36, instead of attaching the fourth conduit to either or both of thethoracic pouch204 andabdominal sac202. While not being limited to a particular theory, it is understood that the alternative embodiments could likewise attach thesecond conduit36 to thefourth conduit206, instead of attaching the second conduit to either or both of thethoracic pouch204 andabdominal sac202.
• It is understood that the size of the sacs, pouches, filters and conduits are preferably determined in accordance with several factors, such as the flow rate desired, the rate of clearance of wastes, and the size, metabolism, fluid intake, nutritional status, cardiac output, thickness of blood and concentration of blood of the patient. For example, an abdominal sac would be largerfor an adult (e.g., 500 cc-1000 cc) than for a child (e.g., 200 cc-500 cc). The amount of dialysate preferred in the prosthesis would likewise be affected by the size of the prosthesis and the desired output.[0150]
• Yet another advantage of the prostheses described above is that they are generally made of an inert plastic regularly used inside the body for other purposes, as discussed above and readily understood by a skilled artisan. An entire prosthesis weighs less than about a pound, and preferably weighs less than about three ounces. Moreover, once implanted into a patient, the prosthesis is not visible and anatomical structures operate in their natural positions in the body.[0151]
• It should be apparent from the aforementioned description and attached drawings that the concept of the present application may be readily applied to a variety of preferred embodiments, including those disclosed herein. For example, in FIG. 3. the[0152]distal end46 of thesecond conduit36 may include relatively large holes so as to allow unconcentrated urine and dialysis in the peritoneum to flow into theconduit36 and theabdominal sac64. Likewise, In FIG. 2, thecentral section66 of thesecond conduit36 has a semi-permeable wall, and can also include relativelylarge holes54, as shown in thebowel18 of FIG. 3. Similarly, in lieu of the relativelylarge holes54 located in thesecond conduit36 and thesemi-permeable membrane72 within thebowel18 of FIG. 3, theconduit36 within thebowel18 can be constructed like thecentral region66 of theconduit36 shown in FIG. 2. That is, in FIG. 3, theconduit36 within thebowel18 can be formed of a semi-permeable membrane. Moreover, in FIG. 4, instead of coupling the distal end of the second conduit to thedialysis sac84, the distal end may extend to and end in the peritoneal space to return a percentage of the fluid to the peritoneum. In this example thedistal end46 of theconduit36 should either be of a very small diameter, or employ a moderate pressure one-way valve46 therein to control the flow of fluid into the peritoneal space in a manner that allows adequate residence time for the bowel to absorb water from the unconcentrated urine passing therethrough, but not such as to prevent flow of partially concentrated urine into the peritoneal space for lymphatic reabsorption and recycling through the entire system. Furthermore, in FIGS. 7 and 8, instead of having two sections or legs of a conduit communicate within the bowel, it is understood that the conduit could be constructed so that any number of sections or legs, including one, would extend into and communicate within the bowel. In addition, theureter24 could be connected directly to thebowel18, thus bypassing theappendix22. In this preferred embodiment, theappendix22 would not be used.
• It is within the scope of the invention that features of the exemplary embodiments discussed above can also be used in other of the exemplary embodiments. For example, as an alternative to the[0153]disk filter138 shown in FIG. 7, thesemi-permeable membrane72 shown in FIG. 3 could be used to extend about the conduits in the section ofbowel18. Moreover, portions of thefirst leg174 andsecond leg176 of thethird conduit158 that extend into thebowel18 could alternatively be formed of a semi-permeable membrane, as shown for thesecond conduit36 in FIG. 2. In addition, while not preferred, thefirst conduit26 of any of the embodiments could includeapertures54, as shown in FIG. 3. Also, the conduits shown in FIG. 10 could be augmented or replaced by other conduits as shown by example in FIGS.1-9. For example, thefourth conduit206 could be supplanted by a conduit having the structure exemplified by thesecond conduit36 of FIG. 2.
• Without further elaboration the foregoing will so fully illustrate my invention that others may, by applying current or future knowledge, readily adapt the same for use under various conditions of service.[0154]

Claims (22)

What is claimed is:

1. A prosthesis for dialysis, comprising:

an abdominal sac adapted to include a dialysate therein, said abdominal sac including a semi-permeable membrane outer wall, said abdominal sac adapted to be retained in the abdominal region of a patient's body with said semi-permeable membrane outer wall in communication with unconcentrated urine in the abdominal region for receiving unconcentrated urine through said semi-permeable membrane outer wall without permitting dialysate to exit through said outer wall of said abdominal sac;

a fluid guide conduit adapted to receive the unconcentrated urine and dialysate from the abdominal sac and to communicate the dialysate back into the abdominal sac for recirculation; and

a conduit extension extending from said fluid guide conduit and adapted to receive the unconcentrated urine from said fluid guide conduit, said conduit extension adapted to extend into and terminate in a section of the patient's bowel separated from the patient's GI tract to communicate the unconcentrated urine in said conduit extension with the section of bowel for concentrating the urine within the section of bowel.

2. The prosthesis ofclaim 1, wherein said conduit extension includes a first conduit section and a second conduit section, said first and second conduit sections adapted to extend into and terminate in the section of the patient's bowel.

3. The prosthesis ofclaim 1 wherein said region of said conduit extension within the section of the patient's bowel includes apertures for communicating the unconcentrated urine in said conduit within walls of the section of bowel.

4. The prosthesis ofclaim 3, wherein said fluid guide conduit is adapted to extend through the section of the patient's bowel, a region of said fluid guide conduit arranged to communicate the unconcentrated urine in said fluid guide conduit with the section of bowel for concentrating the urine within the section of bowel.

5. The prosthesis ofclaim 1, further comprising an exit port arranged in the section of bowel, the exit port adapted to direct concentrated urine from the section of bowel to the urinary bladder of a patient.

6. The prosthesis ofclaim 5, further comprising a filter between said fluid guide conduit and the exit port, said filter having a semipermeable membrane for filtering urine to the exit port without permitting dialysate to exit through said membrane.

7. The prosthesis ofclaim 1 wherein said fluid guide conduit includes a urine transfer sac and said conduit extension includes a urine receiving sac, said urine transfer sac and said urine receiving sac being separated by a filter adapted to permit unconcentrated urine to pass from said urine transfer sac into said urine receiving sac, and adapted to preclude the dialysate from exiting through said filter.

8. The prosthesis ofclaim 1, wherein the fluid guide conduit includes:

a first conduit section communicating said abdominal sac with a pouch adapted to be placed in the thoracic region of the patient's body, and

a second conduit section communicating with the pouch and adapted to communicate the dialysate back into the abdominal sac.

9. The prosthesis ofclaim 8, wherein said conduit extension includes a third conduit adapted to extend from said second conduit into the section of bowel.

10. The prosthesis ofclaim 9, wherein said second and third conduits are separated by a filter that permits urine to pass from said second conduit to said third conduit, but precludes dialysate from passing through said filter.

11. The prosthesis ofclaim 9, wherein said third conduit includes a first conduit section and a second conduit section, said first and second conduit sections adapted to extend into and terminate in the section of the patient's bowel.

12. The prosthesis ofclaim 1 further comprising a connector adapted to direct the concentrated urine from the section of bowel to the urinary bladder of the patient.

13. The prosthesis ofclaim 12, wherein the connector includes the right ureter connecting the bowel to the urinary bladder.

14. The prosthesis ofclaim 13, wherein the connector includes the appendix or cecum.

15. The prosthesis ofclaim 1, wherein said fluid guide conduit includes a one way valve for permitting the unconcentrated urine to flow only in a direction from the abdominal region towards said conduit extension.

16. The prosthesis ofclaim 1, wherein said conduit extension includes a one way valve between said fluid guide conduit and the section of the patient's bowel for permitting the unconcentrated urine to flow only in a direction from said fluid guide conduit towards the section of bowel.

17. The prosthesis ofclaim 1, further comprising a second fluid guide conduit adapted to receive the unconcentrated urine and dialysate from the abdominal sac and to communicate the dialysate back into the abdominal sac for recirculation, said second fluid guide conduit further adapted to extend into the section of the patient's bowel separated from the patient's GI tract to communicate the unconcentrated urine in said second fluid guide conduit with the section of bowel for concentrating the urine within the section of bowel.

18. The prosthesis ofclaim 1, further comprising a pump adapted to move the unconcentrated urine and dialysate within the prosthesis.

19. The prosthesis ofclaim 18, wherein said pump includes an implantable mechanical or electrical pump.

20. The prosthesis ofclaim 18, wherein said pump includes a thoracic pouch in fluid communication with said abdominal sac and adapted for implantation into the thoracic region of the patient

21. A continuous internal peritoneal dialysis method comprising containing unconcentrated urine in the abdominal region of a patient, and directing the contained unconcentrated urine into a section of bowel in which the urine is concentrated for removal from the patient.

22. The method ofclaim 21, further comprising separating the section of bowel from the GI track of the patient, and connecting the section of bowel with the urinary system of the patient.

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