A soft cassette includes a body including a flexible material and first and second component. The body defines first and second lumens and first and second chambers. The first lumen extends between first and second ends. The first chamber is in the first lumen such that fluid passing through the first lumen passes through the first chamber. The second lumen is fluidly connected to the first lumen at a first junction between the first end and the first chamber and a second junction between the second end and the first chamber such that fluid passing through the second lumen bypasses the first chamber. The second chamber is in the second lumen. The first component is on a first side of the second chamber and includes a first ferromagnetic metal or magnet. The second component is on a second side of the second chamber and includes a second ferromagnetic metal magnet.

Described are fluid pumping and fluid handling systems, which may be suitable for use in medical devices, such as artificial or extracorporeal blood pumping systems. The systems can include a dual housing configuration for pneumatic actuation comprising a main housing containing a pump cassette comprising a pneumatically actuated pump and pneumatically actuated valves. The pump can include a pump actuation chamber and pump pneumatic port, and the valves can each include a valve actuation chamber and valve pneumatic port. Connecting tubes can be used to fluidly connect the pump actuation ports and valve actuation ports to a tube-support housing having a first side receiving one end of each connecting tube and a second side providing a pneumatic interface arranged to connect to an array of pneumatic receptacles on a base unit of the system to facilitate easy, compact and accurate pneumatic interconnection between the pump cassette and the base unit.

Described are embodiments that include methods and devices for separating components from multi-component fluids. Embodiments may involve use of separation vessels and movement of components into and out of separation vessels through ports. Embodiments may involve the separation of plasma from whole blood. Also described are embodiments that include methods and devices for positioning portions, e.g., loops, of disposables in medical devices. Embodiments may involve use of surfaces for automatically guiding loops to position them into a predetermined position.

A dialysis system may include a blood circuit, a cassette, a subsystem having a processor, a sensor, and a blood pumping mechanism, a housing in which the subsystem is arranged, a movable support arranged in the housing and configured to hold the sensor and/or the blood pumping mechanism of the subsystem, a cassette holder configured to removably receive the cassette, and a loading system. The loading system may be configured to move the movable support, e.g. by an axial movement, to a first position and to a second position relatively to the housing while the cassette holder is fixedly arranged in the housing. The loading system may have an electric motor controlled by the processor, a drive assembly coupled to the electric motor, and a guiding assembly configured to cooperate with the drive assembly.

A prismatic reflector is provided for incorporation into a centrifugal separation chamber. The prismatic reflector is formed of a light-transmissive material and includes inner and outer walls and first and second end walls. The inner wall is configured to receive light traveling along an initial path and transmit the light to the first end wall, with the first end wall receiving the light transmitted through the inner wall and directing the light toward the second end wall in a direction that is angled with respect to the initial path. The second end wall receives the light from the first end wall and transmits the light out of the prismatic reflector. The initial path of the light may be in a direction toward a rotational axis of the centrifugal separation chamber, with the prismatic reflector redirecting the light into a direction substantially parallel to the rotational axis.

A modular cassette is provided for separating a composite fluid into at least two component parts thereof during centrifugation. The modular cassette includes: a housing defining a fluid inlet, a fluid outlet, and a chamber for fluid separation; a fluidic channel configured to provide fluid communication between at least two components of the modular cassette; a heat expanding valve including: a flow pathway including undulations configured to facilitate closing of the fluidic channel, wherein the heat expanding valve occludes one or more of the undulations of the flow pathway to close the fluidic channel; and a heating element configured to actuate the heat expanding valve.

A fluid separation device includes a centrifuge in which a fluid is separated into at least two components, with an interface therebetween. At least a portion of one of the separated fluid components is removed from the centrifuge and flows through a vessel. Light is reflected off of the separated fluid component in the vessel and received and analyzed to determine its main wavelength. If the main wavelength is higher than a maximum value, a target location of the interface is changed. If the main wavelength is less than the maximum value, then the location of the interface is compared to the target location. When the interface is sufficiently close to the target location, the optical density of the separated fluid component in the vessel is compared to a minimum value. If the optical density is less than the minimum value, the target location of the interface is changed.

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.

Dialysis systems comprising actuators that cooperate to perform dialysis functions and sensors that cooperate to monitor dialysis functions are disclosed. According to one aspect, such a hemodialysis system comprises a user interface model layer, a therapy layer, below the user interface model layer, and a machine layer below the therapy layer. The user interface model layer is configured to manage the state of a graphical user interface and receive inputs from a graphical user interface. The therapy layer is configured to run state machines that generate therapy commands based at least in part on the inputs from the graphical user interface. The machine layer is configured to provide commands for the actuators based on the therapy commands.

Described are embodiments that include methods and devices for separating components from multi-component fluids. Embodiments may involve use of separation vessels and movement of components into and out of separation vessels through ports. Embodiments may involve the separation of plasma from whole blood. Also described are embodiments that include methods and devices for positioning portions, e.g., loops, of disposables in medical devices. Embodiments may involve use of surfaces for automatically guiding loops to position them into a predetermined position.