A fluid controlled system for a cardiac assist device and its method of operation. The cardiac assist device has a cup assembly with a receptacle area. The cup assembly has at least one inflatable membrane that expands into the receptacle area. A single pressure tube connects the cup assembly to a fluid pump. A valve assembly is incorporated into the cardiac assist device. The valve assembly includes at least one valve that controls fluid flow between the inflatable membranes and the pressure tube and/or fluid flow between the receptacle area and the pressure tube. The valve assembly controls fluid flow to advance the cup assembly onto the heart, to maintain the cup assembly in an operable position, to operate the cup assembly, and to remove the cup assembly.

Dialysis systems are disclosed comprising new fluid flow circuits. Systems may include blood and dialysate flow paths, where the dialysate flow path includes balancing, mixing, and/or directing circuits. Dialysate preparation may be decoupled from patient dialysis. Circuits may be defined within one or more cassettes. The fluid circuit fluid flow paths may be isolated from electrical components. A gas supply in fluid communication with the dialysate flow path and/or the dialyzer able to urge dialysate through the dialyzer and urge blood back to the patient may be included for certain emergency situations. Fluid handling devices, such as pumps, valves, and mixers that can be actuated using a control fluid may be included. Control fluid may be delivered by an external pump or other device, which may be detachable and/or generally rigid, optionally with a diaphragm dividing the device into first and second compartments.

A fluid controlled system for a cardiac assist device and its method of operation. The cardiac assist device has a cup assembly with a receptacle area. The cup assembly has at least one inflatable membrane that expands into the receptacle area. A single pressure tube connects the cup assembly to a fluid pump. A valve assembly is incorporated into the cardiac assist device. The valve assembly includes at least one valve that controls fluid flow between the inflatable membranes and the pressure tube and/or fluid flow between the receptacle area and the pressure tube. The valve assembly controls fluid flow to advance the cup assembly onto the heart, to maintain the cup assembly in an operable position, to operate the cup assembly, and to remove the cup assembly.