A capillary dialyzer comprises: a) a housing; a bundle of semi-permeable hollow fiber membranes; c) end walls supporting the first and second ends of the hollow fiber membranes; d) a first end cap covering a first end of the housing and a second end cap covering a second end of the housing; e) an inlet and an outlet; f) support rings; and g) sealing rings interposed between the end wall and the first end cap and between the end wall and the second end cap, respectively. A circular groove of the end cap which receives the wall of the housing comprises indentations for creating a fluid connection between the inside of the capillary dialyzer and its exterior when the end caps are mounted on the housing but have not yet been welded to the housing.

Systems and methods are disclosed for performing hemodialysis that include fluid handling systems that provide accurate control over the type and level of hemodialysis being performed. The system includes a first pump for pumping dialysate into a dialyzer and a second pump for pumping dialysate out of the dialyzer. The system also includes a third pump that provides improved control of a level of ultrafiltration, hemodiafiltration, or both.

A dialysis apparatus including a dialyzer with an interior sectioned by a blood purification membrane into blood and dialysis flow paths, a blood circuit including vein and artery passages connected to the blood flow path, and a dialysis fluid circuit including a dialysis fluid supply and fluid retrieval passages connected to the dialysis fluid flow path. The apparatus includes a bypass passage allowing communication between the dialysis fluid supply and retrieval passages, a dialysis fluid supply open/close valve provided between a connection position at which the dialysis fluid supply passage is connected to the bypass passage and the dialyzer, a dialysis fluid discharge open/close valve provided between a connection position at which the dialysis fluid retrieval passage is connected to the bypass passage and the dialyzer, a pressurizing device for pressurizing the dialysis fluid circuit, and a depressurizing device for depressurizing the dialysis fluid circuit and a controlling device.

The invention relates to devices, systems, and methods for calculating a bicarbonate concentration in a fluid used in dialysis. The devices, systems, and methods can be used to calculate the bicarbonate concentration in either dialysate or blood. The invention measures the amount of carbon dioxide in both an acidified and non-acidified solution and calculates the bicarbonate concentration based on the difference in carbon dioxide concentrations.

Systems and methods for managing the pH of a dialysate fluid during hemodialysis therapy. The systems and methods adjust dialysate pH and buffer concentration to generate a predetermined total bicarbonate buffer concentration in a dialysate entering a dialyzer. The systems and methods generate a pH-modifying fluid and selectively add the pH modifying fluid to the dialysate in order to accurately control the total bicarbonate buffer concentration in the dialysate entering the dialyzer.

A fluid replenishment circuit is positioned between a dialysis fluid supply passage and a blood circuit and is provided with an online port to and from which a fluid replenishment passage is attached and detached. The online port has is provided with a first bypass passage and an open/close valve that allow a space formed between an inner port and an outer port to communicate with the dialysis fluid supply passage. In a fluid draining procedure, the open/close valve on the bypass passage is opened, and fluid in a dialysis fluid retrieval passage is discharged by a water removal pump. As a result, air flows into the first bypass passage through the outer port, and is further caused to flow via the dialysis fluid supply passage through a replenishment fluid supply passage into the blood circuit so that fluid is removed from the fluid replenishment passage.

Systems and methods for managing the pH of a dialysate fluid during hemodialysis therapy. The systems and methods adjust dialysate pH and buffer concentration to generate a predetermined total bicarbonate buffer concentration in a dialysate entering a dialyzer.

The invention relates to an extracorporeal blood treatment apparatus comprising a blood treatment unit 1 that is divided by a semipermeable membrane 2 into a first compartment 3, which is part of a fluid system II, and a second compartment 4, which is part of an extracorporeal blood circuit I. The invention also relates to a method for operating a blood treatment apparatus of this kind. The blood treatment apparatus according to the invention has a pressure-based checking device 32 which interacts with the control unit 31 for a valve device 21 and is designed such that a fluid connection between an upstream portion 20A and a downstream portion 20B of a flow path 20 for a special operating mode can only be established if the pressure-based checking device 32 detects an operating state in which it is ensured that fluid in the flow path 20 for a special operating mode flows towards a flow path 10 leading to a drain 11. This ensures that the fluid in question can only flow into the flow path 10 that leads to the drain 11, and cannot get into another flow path 8 in which fresh treatment fluid is located.

The invention relates to devices, systems, and methods for calculating a bicarbonate concentration in a fluid used in dialysis. The devices, systems, and methods can be used to calculate the bicarbonate concentration in either dialysate or blood. The invention measures the amount of carbon dioxide in both an acidified and non-acidified solution and calculates the bicarbonate concentration based on the difference in carbon dioxide concentrations.

A blood circuit and a dialysate circuit bidirectionally circulate a fluid through a blood purification membrane of a blood purifier, and include a first flow route that causes a dialysate to flow from the dialysate circuit into the blood circuit through a connection flow route connecting the dialysate circuit to the blood circuit while bypassing the blood purifier, and a second flow route that causes the dialysate to flow from the dialysate circuit into the blood circuit through the blood purification membrane. The controller performs control such that blood in the blood circuit is returned to the body by feeding the dialysate to one of these flow routes, determine if a flow amount of the dialysate reaches a predetermined flow amount, and control such that the blood in the blood circuit is returned to the body by feeding the dialysate to the other one of these flow routes.