Hemodialysis systems are described. A hemodialysis system may include a dialysate flow path through which dialysate is passed from a dialysate reservoir, which includes a valved vent to atmosphere, to an ultrafilter. The dialysate flow path includes a pneumatically actuated diaphragm-based dialysate pump for pumping fluid from the dialysate reservoir to the ultrafilter. The hemodialysis system may include a controller for controlling pneumatic actuation pressure delivered to the dialysate pump and at least one valve connecting the dialysate reservoir vent to the atmosphere. The hemodialysis system may be configured to actuate the dialysate pump and the at least one valve to introduce air into the dialysate flow path and expel liquid from the dialysate flow path to a drain.

A hemodialysis apparatus comprising diaphragm pumps for the movement of both dialysate and blood, and under the control of a controller, is capable of detecting blood flow conditions that give rise to an alarm and implement procedures to adjust, pause, or halt the pumping of dialysate and/or blood. The controller can direct the application of a time-varying pressure to fluid in the control chamber of a blood pump, and monitor the resulting pressure waveform during a fill stroke of the blood pump. A deviation of the measured pressure variation from an expected value can give rise to an alert to a user and to the initiation of an adjustment, pause, or cessation of the dialysate pump's activity.

A dialysis fluid system includes a dialysis fluid inlet; a dialysis fluid outlet; a pump positioned and arranged to pump dialysis fluid through the dialysis fluid inlet and the dialysis fluid outlet; and an inductive heater located between the dialysis fluid inlet and the dialysis fluid outlet, the inductive heater including a fluid flowpath positioned and arranged to receive non-heated dialysis fluid from the dialysis fluid inlet and to output heated dialysis fluid to the a dialysis fluid outlet, a conductive heater element located within the fluid flowpath so as to be or act as a secondary coil of a transformer, and a primary coil of the transformer located outside of the fluid flowpath and positioned so as to magnetically induce a current into the conductive heater element, causing the conductive heater element and surrounding fluid to heat.

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.

A pumping cassette including a housing having at least two inlet fluid lines and at least two outlet fluid lines. At least one balancing pod within the housing and in fluid connection with the fluid paths. The balancing pod balances the flow of a first fluid and the flow of a second fluid such that the volume of the first fluid equals the volume of the second fluid. The balancing pod also includes a membrane that forms two balancing chambers. Also included in the cassette is at least two reciprocating pressure displacement membrane pumps. The pumps are within the housing and they pump the fluid from a fluid inlet to a fluid outlet line and pump the second fluid from a fluid inlet to a fluid outlet.

The invention provides a blood treatment device comprising: a dialyser; an inlet pump assembly; an outlet pump assembly; and a control system. The inlet pump assembly configured to deliver a first volume of dialysate from a dialysate source to the dialyser in an inlet pump cycle having a dialysate delivery stroke. The outlet pump assembly configured to remove a second volume of dialysate from the dialyser and deliver the dialysate away from the dialyser in an outlet pump cycle having a dialysate removal stroke. The control system is configured to operate the inlet pump assembly in the inlet pump cycle, and configured to operate the outlet pump assembly in the outlet pump cycle. For each inlet pump cycle there is a corresponding outlet pump cycle, and each inlet pump assembly dialysate delivery stroke has a commencement time t.sub.1 and a termination time h, and each outlet pump assembly dialysate removal stroke has a commencement time t.sub.3 and a termination time t.sub.4. The blood treatment device is operable such that either: each dialysate removal stroke commencement time t.sub.3 is after the respective corresponding dialysate delivery stroke commencement time ti and before the respective corresponding dialysate delivery stroke termination time t.sub.2; or each dialysate delivery stroke commencement time t.sub.1 is after the respective corresponding dialysate removal stroke commencement time t.sub.3 and before the respective corresponding dialysate removal stroke termination time t.sub.4.

An improved valve leak detection system. The improved valve leak detection system comprises a membrane pump defining a flow path arranged to be opened and closed by at least one valve, a measuring device; a comparator; and a signal generator. The measuring device is configured to determine a conductivity value between two points on the flow path of the membrane pump, one point arranged upstream of the at least one valve and the other point arranged downstream of the at least one valve. The measuring device measures the conductivity value when the at least one valve is closed. The comparator is configured to continuously monitor the conductivity value. The signal generator is arranged to provide an output signal when the conductivity value is indicative of a valve leak condition for a set number of measurements within a set period of time.

A processor of a medical device configured to communicate with a remote server can be programmed to protect the medical device from exposure to unauthorized or malicious software. A system or method to implement this form of protection can include, for example, at least one processor on the medical device, a control software module that controls the operation of the medical device and is executable on the processor, a data management module that manages data flow to and from the control software module from sources external to the medical device, and an agent module that has access to a limited number of designated memory locations in the medical device. In addition, a hemodialysis apparatus can be configured to operate in conjunction with an apparatus for providing purified water from a source such as a municipal water supply or a well. A system for controlling delivery of purified water to the hemodialysis apparatus can comprise a therapy controller of the hemodialysis apparatus configured to communicate with a controller of a water purification device, and a user interface controller of the hemodialysis apparatus configured to communicate with the therapy controller, and to send data to and receive data from a user interface.

Disclosed are hemodialysis and similar dialysis systems including fluid flow circuits. Hemodialysis systems may include a blood flow path, and a dialysate flow path including balancing, mixing, and/or a directing circuits. Preparation of dialysate may be decoupled from patient dialysis. Circuits may be defined within one or more cassettes. The fluid circuit and/or the various fluid flow paths may be isolated from electrical components. A gas supply may be provided that, when activated, is able to urge dialysate through the dialyzer and blood back to the patient. Such a system may be useful during a power failure. The hemodialysis system may also include fluid handling devices, such as pumps, valves, mixers, etc., actuated using a control fluid. The control fluid may be delivered to the fluid handling devices using a detachable external pump. The fluid handling devices may have a spheroid shape with a diaphragm dividing it into two compartments.

A hybrid hemodialysis (HD)/peritoneal dialysis (PD) system includes: a reservoir; a weigh scale operably coupled with the reservoir; and at least one controller programmed to run (i) an HD treatment in which blood is pumped to a blood compartment of a dialyzer, fresh HD dialysis fluid is pumped to a dialysis fluid compartment of the dialyzer, and used HD dialysis fluid is pumped from the dialysis fluid compartment of the dialyzer to the reservoir, and at a different time (ii) a PD treatment in which fresh PD dialysis fluid is pumped to a patient and used PD dialysis fluid is pumped from the patient to the reservoir.