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.

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 system and method for balancing flows of renal replacement fluid is disclosed. The method uses pressure controls and pressure sensing devices to more precisely meter and balance the flow of fresh dialysate and spent dialysate. The balancing system may use one or two balancing devices, such as a balance tube, a tortuous path, or a balance chamber.

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.

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.

Systems and methods are provided for therapeutic red blood cell exchange and/or therapeutic plasma exchange. A blood separation device includes a centrifugal separator, a spinning membrane separator drive unit, a pump system, and a controller. Blood is conveyed through a fluid flow circuit into either the centrifugal separator or the spinning membrane separator, which separates out the target blood component (red blood cells, in the case of therapeutic red blood cell exchange, or plasma, in the case of therapeutic plasma exchange). The target blood component is retained in the circuit as a waste product, while a replacement fluid is added to the remaining blood component(s), which is then conveyed to a recipient. In addition to allowing for execution of an exchange procedure using either a centrifugal separator or a spinning membrane separator drive unit, the blood separation device also allows for the use of differently sized spinning membrane separators.

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 medical functional device with a valve seat for a check valve wherein the check valve is embodied such that it takes, in addition to a first position which is suitable for gas sterilization, a second, functional position, by means of applying force onto a section of the check valve or by means of moving or shifting the section, in which the check valve adopts a check or non-return function, wherein the check valve is embodied such that it remains in the second position after release or shortfall of the force or the moving effect following an accomplished transfer into the second position.

Mid-procedure termination of a mononuclear cell collection procedure may prevent collection of an amount of red blood cells that is required to harvest a complete mononuclear cell product. Blood separation systems and methods are provided for minimizing the impact of or recovering from mid-procedure termination of such a mononuclear cell collection procedure. According to one approach, blood or separated red blood cells are conveyed into a red blood cell collection container relatively early in the procedure to minimize the impact of a later termination of the procedure. According to another approach, blood and/or separated red blood cells within a fluid processing assembly are redirected through the fluid processing assembly following mid-procedure termination to allow for at least partial mononuclear cell collection. According to yet another approach, a double-needle fluid processing assembly may be converted into a single-needle configuration to allow for continued processing following mid-procedure termination.

A drain cassette for a dialysis unit has a fluid channel between venous and arterial connection ports, and a valve may controllably open and close fluid communication between a drain outlet port and the venous connection port or the arterial connection port. A blood circuit assembly and drain cassette may be removable from the dialysis unit, e.g., by hand and without the use of tools. A blood circuit assembly may include a single, unitary member that defines portions of a pair of blood pumps, control valves, channels to accurately position flexible tubing for an occluder, an air trap support, and/or other portions of the assembly. A blood circuit assembly engagement device may assist with retaining a blood circuit assembly on the dialysis unit, and/or with removal of the assembly. An actuator may operate a retainer element and an ejector element that interact with the assembly.