The present invention generally relates to hemodialysis and similar dialysis systems, including a variety of systems and methods that would make hemodialysis more efficient, easier, and/or more affordable. One aspect of the invention is generally directed to new fluid circuits for fluid flow. In one set of embodiments, a hemodialysis system may include a blood flow path and a dialysate flow path, where the dialysate flow path includes one or more of a balancing circuit, a mixing circuit, and/or a directing circuit. Preparation of dialysate by the preparation circuit, in some instances, may be decoupled from patient dialysis. In some cases, the circuits are defined, at least partially, within one or more cassettes, optionally interconnected with conduits, pumps, or the like. In one embodiment, the fluid circuit and/or the various fluid flow paths may be at least partially isolated, spatially and/or thermally, from electrical components of the hemodialysis system. In some cases, a gas supply may be provided in fluid communication with the dialysate flow path and/or the dialyzer that, when activated, is able to urge dialysate to pass through the dialyzer and urge blood in the blood flow path back to the patient. Such a system may be useful, for example, in certain emergency situations (e.g., a power failure) where it is desirable to return as much blood to the patient as possible. The hemodialysis system may also include, in another aspect of the invention, one or more fluid handling devices, such as pumps, valves, mixers, or the like, which can be actuated using a control fluid, such as air. In some cases, the control fluid may be delivered to the fluid handling devices using an external pump or other device, which may be detachable in certain instances. In one embodiment, one or more of the fluid handling devices may be generally rigid (e.g., having a spheroid shape), optionally with a diaphragm contained within the device, dividing it into first and second compartments.

A photopheresis system (200) is disclosed, and that may be configured to execute one or more protocols. These protocols include: 1) protocols (400; 430; 460) for purging air out of a centrifuge bowl (210) used by the photopheresis system (200); 2) protocols (500; 510 550) for assessing the installation/operation of one or more pressure domes (330) used by the photopheresis system (200); and 3) protocols (580; 600; 660; 700; 740) for collecting buffy coat from blood processed by the photopheresis system (200).

To provide a blood treatment filter device capable of efficiently utilizing a blood treatment filter. A blood treatment filter device 20 has a filter sheet 26 through which a specific component among components forming blood is harder to pass than other components and a spacer sheet 27 through which the specific component is easier to pass than through the filter sheet 26. The filter sheet 26 has filter through-holes 39 disposed at intervals. The filter sheet 26 and the spacer sheet 27 are spirally wound in an overlapped state. The filter device 20 has seals 31 sealing both end portions in the longitudinal direction of a wound body 25 formed by the filter sheet 26 and the spacer sheet 27 which are spirally wound in a fluid-tight manner. The outer peripheral surface of the wound body 25 is formed by the filter sheet 26.

A method for operating a dialysis cassette including a flexible membrane that covers a pump chamber includes allowing a source of fluid to fluidly communicate with the pump chamber of the dialysis cassette, filling the pump chamber with the fluid from the source, mechanically extending the flexible membrane into the pump chamber with a piston head to expel the fluid from the pump chamber through a flow path, and directly sensing a pressure of the fluid flowing through the flow path at a location of the dialysis cassette adjacent to the pump chamber and using the sensed pressure to perform a test prior to delivering fluid to a patient.

A filter CF1 for filtering dialysis fluid comprises the following: a housing 52 inside of which a filter material 51 is accommodated and which is vertically long; an introduction port 53 that is disposed in the lower part of the housing and that introduces dialysis fluid from an upstream-side flow path 23a; a filtered fluid lead-out port 54 through which filtered dialysis fluid, which has passed through the filter material, is lead out from the upper part of the housing to a downstream-side flow path 23b; and an unfiltered fluid lead-out port 55 through which unfiltered fluid is lead out from the upper part of the housing to a waste fluid flow path 57. When removing the filter from a dialysis fluid circuit 4, fluid is suctioned from the inside of the housing via the upstream-side flow path by using fluid suction means 64A, and a gas is caused to flow into the housing from at least either one of the waste fluid flow path and the downstream-side flow path by using gas inflow means 65. The fluid may be suctioned from the downstream-side flow path and the gas may be caused to flow in from the upstream-side flow path, or the fluid may be suctioned from the waste fluid flow path and the gas may be caused to flow in from the downstream-side flow path. Residual fluid in the filter can be reduced.

A method for operating a dialysis cassette including a flexible membrane that covers a pump chamber includes allowing a source of fluid to fluidly communicate with the pump chamber of the dialysis cassette, filling the pump chamber with the fluid from the source, mechanically extending the flexible membrane into the pump chamber with a piston head to expel the fluid from the pump chamber through a flow path, and directly sensing a pressure of the fluid flowing through the flow path at a location of the dialysis cassette adjacent to the pump chamber and using the sensed pressure to perform a test prior to delivering fluid to a patient.

A method for priming a renal therapy machine is disclosed. The method includes communicating a source of a physiologically compatible solution with a blood circuit and moving the physiologically compatible solution from the source to the blood circuit. The method also includes moving the physiologically compatible solution through the blood circuit to prime the blood circuit. The method further includes moving the physiologically compatible solution from the blood circuit though porous fibers of a blood filter, causing air to be purged from the blood circuit and into a dialysis fluid circuit portion of the blood filter.

The invention relates to a method for venting a dialyzer which has a dialyzate chamber, a blood chamber and a semi-permeable dialyzer membrane separating these two chambers, wherein an overpressure is generated in the dialyzate chamber with respect to the blood chamber for removing air inclusions lying at the surface of the membrane at the dialyzate chamber side after a filling of the dialyzate chamber and before a filling of the blood chamber.

A method controls a device for extracorporeal blood gas exchange. The device has a membrane as a gas-liquid barrier between a bloodstream and a gas stream. The membrane further makes possible a passing over of the carbon dioxide content from the bloodstream into the gas stream. The device has at least one actuator. A change in a value of an operating parameter of the actuator brings about a change in a value of the carbon dioxide content that passes over from the bloodstream into the gas stream. The method further includes providing breathing gas information that indicates a carbon dioxide concentration in breathing gas and providing a control signal, which indicates a request for setting a value of the operating parameter and changing of the value of the operating parameter as a function of the carbon dioxide concentration in the breathing gas.

A dialysis bloodline set includes an arterial chamber with upper, lower and central portions, in which the central portion forms a vertical riser tube having a maximum section area less than that of the lower portion. The lower portion has a shoulder which is positioned to deflect blood entering the lower portion to flow across the aperture at the lower end of the riser tube. The bloodline is prepared by filling the arterial chamber with a priming liquid which extends to a level part way up the riser tube and which is partially displaced by the blood to leave a plug of priming liquid within the base of the riser tube above the blood. The plug of priming liquid separates the blood from a gas in the upper part of the arterial chamber while the blood flowing across the aperture forms a dynamic interface.