Abstract: A pump cassette is disclosed. The pump cassette includes a housing having at least one fluid inlet line and at least one fluid outlet line. The cassette also includes at least one reciprocating pressure displacement membrane pump within the housing. The pressure pump pumps a fluid from the fluid inlet line to the fluid outlet line. A hollow spike is also included on the housing as well as at least one metering pump. The metering pump is fluidly connected to the hollow spike on the housing and to a metering pump fluid line. The metering pump fluid line is fluidly connected to the fluid outlet line.

Abstract: Automated control mechanisms and methods for controlling fluid flow in a hemodialysis apparatus are described. The methods can involve a controller receiving information from a pressure sensor in a control chamber of a reciprocating diaphragm-based blood pump and causing the application of a time-varying pressure waveform on a diaphragm of the blood pump during a fill-stroke of the blood pump. The controller can be configured and programmed to monitor a pressure variation in the control chamber measured by the pressure sensor and to compare the measured pressure variation to a pre-determined value. Based on such comparison, the controller can initiate a procedure to pause or stop a dialysate pump of the hemodialysis apparatus if the magnitude of the measured pressure variation deviates from the pre-determined value.

Abstract: Systems for monitoring fluid flow in an extracorporeal blood circuit are described. The blood circuit of such systems can include plod pump having a pumping chamber of the blood pump separated from a control chamber of the blood pump by a flexible diaphragm. The control chamber can be configured to transmit positive or negative pressure to operate the diaphragm. The system can include a pressure sensor configured to measure pressure in the control chamber of the blood pump, and a controller configured to receive information from the pressure sensor and to control the delivery of pressure to the control chamber of the blood pump. The controller can also be configured to cause the application of a time-varying pressure waveform on the blood pump diaphragm during a fill-stroke of the blood pump, and to monitor a pressure variation in the control chamber measured by the pressure sensor.

Abstract: 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.

Abstract: 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.

Abstract: A blood circuit assembly for a dialysis unit may include an organizing tray, a pair of pneumatic pumps mounted to the organizing tray for circulating blood received from a patient through a circuit including a dialyzer unit and returned to the patient, an air trap mounted to the organizing tray arranged to remove air from blood circulating in the circuit, a pair of dialyzer connections arranged to connect to the inlet and outlet of a dialyzer unit, and a pair of blood line connectors, one inlet blood line connector for receiving blood from the patient and providing blood to the pneumatic pumps and the other outlet blood line connector for returning blood to the patient.

Abstract: A fluid handling cassette, such as that useable with an automated peritoneal dialysis (APD) cycler device or other infusion apparatus, may include a generally planar body having at least one pump chamber formed as a depression in a first side of the body and a plurality of flowpaths for a fluid that includes a channel. A patient line port may be arranged for connection to a patient line and be in fluid communication with the at least one pump chamber via at least a first one of said flowpaths, and an optional membrane may be attached to the first side of the body over the at least one pump chamber. In one embodiment, the membrane may have a pump chamber portion with an unstressed shape that generally conforms to the depression of the at least one pump chamber in the body and is arranged to be movable for movement of the fluid in a useable space of the at least one pump chamber.

Abstract: Embodiments of the present invention relate generally to certain types of reciprocating positive-displacement pumps (which may be referred to hereinafter as “pods,” “pump pods,” or “pod pumps”) used to pump fluids, such as a biological fluid (e.g., blood or peritoneal fluid), a therapeutic fluid (e.g., a medication solution), or a surfactant fluid. The pumps may be configured specifically to impart low shear forces and low turbulence on the fluid as the fluid is pumped from an inlet to an outlet. Such pumps may be particularly useful in pumping fluids that may be damaged by such shear forces (e.g., blood, and particularly heated blood, which is prone to hemolysis) or turbulence (e.g., surfectants or other fluids that may foam or otherwise be damaged or become unstable in the presence of turbulence).

Abstract: 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.

Abstract: A fluid handling cassette, such as that useable with an automated peritoneal dialysis (APD) cycler device or other infusion apparatus, may include a generally planar body having at least one pump chamber formed as a depression in a first side of the body and a plurality of flowpaths for a fluid that includes a channel. A patient line port may be arranged for connection to a patient line and be in fluid communication with the at least one pump chamber via at least a first one of said flowpaths, and an optional membrane may be attached to the first side of the body over the at least one pump chamber. In one embodiment, the membrane may have a pump chamber portion with an unstressed shape that generally conforms to the depression of the at least one pump chamber in the body and is arranged to be movable for movement of the fluid in a useable space of the at least one pump chamber.

Abstract: Hemodialysis and similar dialysis systems including a variety of systems and methods that make hemodialysis more efficient, easier, and/or more affordable, and include new fluid circuits for fluid flow in hemodialysis systems and a blood pump. The blood pump is configured to pump blood to a dialyzer of a hemodialysis apparatus and comprises a pneumatically actuated or controlled reciprocating diaphragm pump. The diaphragm of the pump comprises a flexible membrane formed or molded to conform to a curved inner wall of a pumping chamber or control chamber of the pump, and the diaphragm is pre-formed or molded to have a control side taking a convex shape, so that any elastic tension on the diaphragm is minimized when fully extended into a control chamber of the pump.

Abstract: A pump cassette is disclosed. The pump cassette includes a housing having at least, one fluid inlet line and at least one fluid outlet line. The cassette also includes at least one reciprocating pressure displacement membrane pump within the housing. The pressure pump pumps a fluid from the fluid inlet line to the fluid outlet line. A hollow spike is also included on the housing as well as at least one metering pump The metering pump is fluidly connected to the hollow spike on the housing and to a metering pump fluid line. The metering pump fluid line is fluidly connected to the fluid outlet line.

Abstract: A rotatable door latch for a door hingedly attached the housing of a device, which in some embodiments may be a medical device for handling fluids, such as a peritoneal dialysis cycler with pump cassette. In an embodiment, the door is configured to close over an installed cassette against a front panel of the housing, the door latch configured to capture the head of a post mounted to the housing. After capturing the head of the post and rotating the door latch, a slot in the latch flanked by a ramp or cam feature slides against the post head, the ramp increasing in thickness to progressively increase the closing force between the door and the post head. Upon full closure of the door latch, a detent at the end of the slot provides a maintenance closing force between the door and the post head.

Abstract: 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.

Abstract: A reciprocating positive displacement pump comprises a flexible diaphragm fluidically separating a pumping chamber from an actuation chamber. The membrane may include bumps or other features on the side of the membrane facing the pumping chamber that space at least a portion of the membrane away from the rigid chamber wall when the membrane is in a minimum-pumping-chamber volume position. Such structures may prevent pockets of fluid from being caught away from the inlet and outlet by keeping portions of the membrane spaced away from the rigid pumping chamber wall even when the pumping chamber volume is at a minimum.

Abstract: A fluid handling cassette, such as that useable with an automated peritoneal dialysis (APD) cycler device or other infusion apparatus, may include a generally planar body having at least one pump chamber formed as a depression in a first side of the body and a plurality of flowpaths for a fluid that includes a channel. A patient line port may be arranged for connection to a patient line and be in fluid communication with the at least one pump chamber via at least a first one of said flowpaths, and an optional membrane may be attached to the first side of the body over the at least one pump chamber. In one embodiment, the membrane may have a pump chamber portion with an unstressed shape that generally conforms to the depression of the at least one pump chamber in the body and is arranged to be movable for movement of the fluid in a useable space of the at least one pump chamber.

Abstract: Components for a medical infusion fluid handling system, such as an APD system, in which one or more lines (such as solution lines), spikes or other connection ports may be automatically capped and/or de-capped. This feature may provide advantages, such as a reduced likelihood of contamination since no human interaction is required to de-cap and connect the lines, spikes or other connections. For example, a fluid handling cassette may include one or more caps that cover a corresponding spike and include a raised and/or recessed feature to assist in removal of the cap from the cassette. A solution line cap may include a hole and recess, groove or other feature to engage with a spike cap and enable removal of the cap.

Abstract: Improvements in fluid volume measurement systems are disclosed for a pneumatically actuated diaphragm pump in general, and a peritoneal dialysis cycler using a pump cassette in particular. Pump fluid volume measurements are based on pressure measurements in a pump control chamber and a reference chamber in a two-chamber model, with different sections of the apparatus being modeled using a combination of adiabatic, isothermal and polytropic processes. Real time or instantaneous fluid flow measurements in a pump chamber of a diaphragm pump are also disclosed, in this case using a one-chamber ideal gas model and using a high speed processor to obtain and process pump control chamber pressures during fluid flow into or out of the pump chamber. Improved heater control circuitry is also disclosed, to provide added or redundant safety measures, or to reduce current leakage from a heater element during pulse width modulation control of the heater.

Abstract: Improvements in fluid volume measurement systems are disclosed for a pneumatically actuated diaphragm pump in general, and a peritoneal dialysis cycler using a pump cassette in particular. Pump fluid volume measurements are based on pressure measurements in a pump control chamber and a reference chamber in a two-chamber model, with different sections of the apparatus being modeled using a combination of adiabatic, isothermal and polytropic processes. Real time or instantaneous fluid flow measurements in a pump chamber of a diaphragm pump are also disclosed, in this case using a one-chamber ideal gas model and using a high speed processor to obtain and process pump control chamber pressures during fluid flow into or out of the pump chamber. Improved heater control circuitry is also disclosed, to provide added or redundant safety measures, or to reduce current leakage from a heater element during pulse width modulation control of the heater.

Abstract: Components for a medical infusion fluid handling system, such as an APD system, in which one or more lines (such as solution lines), spikes or other connection ports may be automatically capped and/or de-capped. This feature may provide advantages, such as a reduced likelihood of contamination since no human interaction is required to de-cap and connect the one or more lines, the spikes or the other connection ports. For example, a fluid handling cassette may include one or more caps that cover a corresponding spike and include a raised and/or recessed feature to assist in removal of the one or more caps from the cassette. A solution line cap may include a hole and a recess, a groove or other feature to engage with a spike cap and enable removal of the spike cap.