Peritoneal dialysis (PD) is a form of renal replacement therapy that is used in the management of end stage renal failure (ESRF). PD enables the removal of nitrogenous waste products and water from the body, using peritoneal dialysis fluid (PDF) infused via a catheter into the peritoneal cavity. PD is usually performed by the patient at home and is a continuous therapy, which means that it is designed to work all day, every day.
To perform peritoneal dialysis, a catheter is surgically placed through a patient's abdominal wall. Sterile dialysis solution flows into the peritoneum through the catheter, and solute and fluids are exchanged between the peritoneal capillary blood and the dialysis solution in the peritoneal cavity across the peritoneal membrane, the semi-permeable lining of the abdomen, which acts as a filter. The physiological basis of dialysis across the peritoneum involves diffusion, convective transport, and osmosis. Solutes diffuse between the blood and dialysate by diffusive and convective transport, according to their concentration gradient. The rate of solute transport can be variable in different patients, depending on the membrane permeability and the functional surface area of the peritoneal membrane that is in contact with the dialysate. Used dialysis solution remains in the peritoneal cavity for a desired period of time as waste products diffuse from the blood across the peritoneum and into the dialysate. When the dialysate reaches chemical equilibrium, excess fluid is removed by the process of osmosis, using a hypertonic glucose solution, and the fluid is drained from the peritoneal cavity and replaced with new solution. The time when the solution is in the peritoneal cavity and dialysis is occurring is called the dwell time. Most adults use 2 to 3 liters of solution for each dwell. However, the amount of solution and the duration of the dwells are adjusted to each patient's individual needs and can change over time. After the dwell is completed, the solution is drained from the body and replaced with fresh solution in an exchange procedure, and wastes and excess fluid move from the blood vessels in the peritoneal membrane into the solution by diffusion.
Advantages of peritoneal dialysis include the use of relatively simple equipment, treatments that can be maintained by an ambulatory patient, and an overall improvement in patient health due to the frequency of treatments. Disadvantages of peritoneal dialysis include logistical challenges associated with transporting an external catheter or other machines and large volumes of dialysate fluid. PD typically needs to be performed every day, thereby disrupting a patient's daily schedule. PD can also increase the risk of a patient's peritoneum becoming infected with bacteria (peritonitis). Peritonitis, or an inflammation of the peritoneum, can damage the peritoneal membrane, resulting in permeability changes and temporary or permanent catheter withdrawal. The dialysis fluid that is typically used in peritoneal dialysis can cause a reduction in protein levels, low rates of removal of molecular-weight nitrogenous waste products, ultrafiltration, or inadequate fluid removal and extravascular volume expansion, loss of protein, amino acids, and other nutrients into the dialysate, which can all lead to a lack of energy, and in some cases, malnutrition. Some people using peritoneal dialysis also experience a rise in their blood cholesterol levels, which can put them at a greater risk of developing a cardiovascular disease, such as heart attack, or stroke. Other disadvantages can include weight gain, constipation, exit site infections, tunnel infections, stretching of the abdomen, backaches or shoulder pains, fluid leaking, hernias, hemorrhoids, constipation, loss of appetite from glucose absorption, protein and amino acid losses, and fatigue from continuous use, and the like, especially in elderly patients.
The surface area of the peritoneum and diffusion gradients in the large volume of dialysate used during dialysis (approximately 2 to 3 liters of solution) can adversely impact dialysis adequacy. The peritoneal surface area is composed of three exchange entities: the anatomic area, the contact area, and the vascular area. The amount of perfused capillaries within the peritoneal membrane determines the effective peritoneal surface area (EPSA), i.e., the functional area of exchange between the blood and the dialysate. It has been shown that only a fraction of the peritoneum is exposed to dialysate fluid during dialysis. The EPSA that is exposed to dialysate fluid during dialysis prevents some patients from having an effective peritoneal membrane surface area that is suitable for peritoneal dialysis.
There exists a need in the art for an improved dialysis catheter and method of dialysis using a dialysis catheter that will allow for increased filtration during dialysis using a different bodily organ that has a higher effective surface area, such as the lungs, compared to the peritoneum, thereby providing an alternative to peritoneal dialysis. A vascular access catheter and method has not yet been proposed that would solve this problem, thereby avoiding many of the negative side effects of peritoneal dialysis described above.
A dialysis catheter is described herein that provides a long term solution for patients undergoing peritoneal dialysis.
A dialysis catheter is provided that can be inserted into a highly vascularized organ with a large surface area, such as, for example, the lung, as an alternative to using the peritoneum during peritoneal dialysis.
It is a purpose of the invention described herein to provide a dialysis catheter that can be inserted into the bronchi of the lungs as an alternative to the peritoneum.
It is a purpose of the invention described herein to provide a dialysis catheter that can provide an alternative form of infusion and drainage of fluid during dialysis.
It is a purpose of the invention described herein to provide a catheter that can be equipped with at least one sealing means to isolate a target lung region, thereby allowing the isolated area to be filled with dialysate fluid in a manner similar to peritoneal dialysis.
It is a further purpose of this invention to provide a method of using the catheter described herein to perform dialysis treatment within a portion of a patient's lung.
Various other objectives and advantages of the present invention will become apparent to those skilled in the art as more detailed description is set forth below. Without limiting the scope of the invention, a brief summary of some of the claimed embodiments of the invention is set forth below. Additional details of the summarized embodiments of the invention and/or additional embodiments of the invention can be found in the Detailed Description of the Invention.