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 being modeled using a combination of adiabatic, isothermal and polytropic processes. Real time or instantaneous fluid flow measurements in a pump chamber of the 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 element. Improvements are also disclosed in an application of negative pressure during a drain phase in peritoneal dialysis therapy, and to control an amount of intraperitoneal fluid accumulation during the therapy. Improvements in efficiency are also disclosed in movement of fluid into and out of a two-pump cassette and a heater bag of the peritoneal dialysis cycler, and in synchronization of operation of two or more pumps in the peritoneal dialysis cycler or other fluid handling devices using a multi-pump arrangement.

A dialysis machine (e.g., a peritoneal dialysis (PD) machine) can include a pressure sensor mounted at a proximal end of a patient line made of a distensible material that provides PD solution to a patient through a catheter. During treatment, an occlusion can occur at different locations in the patient line and/or the catheter. When an incremental volume of additional solution is provided to the patient line while the occlusion is present, a change in pressure results. The change in pressure depends on the dimensions and the distensibility of the non-occluded portion of the patient line. If the change in pressure, the incremental volume, the properties related to the distensibility of the patient line, and some of the dimensions of the patient line are known, the location of the occlusion can be inferred. The occlusion type can be inferred based on the determined location.

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 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 medical treatment system, such as peritoneal dialysis system, may include control and other features to enhance patient comfort and ease of use. For example, a peritoneal dialysis system may include a control system that can adjust the volume of fluid infused into the peritoneal cavity to prevent the intraperitoneal fluid volume from exceeding a pre-determined amount. The control system can adjust by adding one or more therapy cycles, allowing for fill volumes during each cycle to be reduced. The control system may continue to allow the fluid to drain from the peritoneal cavity as completely as possible before starting the next therapy cycle. The control system may also adjust the dwell time of fluid within the peritoneal cavity during therapy cycles in order to complete a therapy within a scheduled time period. The cycler may also be configured to have a heater control system that monitors both the temperature of a heating tray and the temperature of a bag of dialysis fluid in order to bring the temperature of the dialysis fluid rapidly to a specified temperature, with minimal temperature overshoot.

A dialysis machine (e.g., a peritoneal dialysis (PD) machine) can include a pressure sensor mounted at a proximal end of a patient line made of a distensible material that provides PD solution to a patient through a catheter. During treatment, an occlusion can occur at different locations in the patient line and/or the catheter. When an incremental volume of additional solution is provided to the patient line while the occlusion is present, a change in pressure results. The change in pressure depends on dimensions and a distensibility of a non-occluded portion of the patient line. If the change in pressure, the incremental volume, properties related to the distensibility of the patient line, and some of the dimensions of the patient line are known, a location of the occlusion can be inferred. An occlusion type can be inferred based on the inferred location.

A medical fluid delivery system includes: a medical fluid delivery machine including a component having at least one of associated output data or associated test data; at least one of a (i) component output replacement limit and a component output soft limit for the component or (ii) a component testing replacement limit or a component testing soft limit for the component; and a computer programmed to store at least one of (i) or (ii), and for (i) analyze the output data to provide a first indication of how well the component is performing relative to the component output replacement limit and the component output soft limit, and for (ii) analyze the test data to provide a second indication of how well the at least one component is testing relative to the component testing replacement limit and the component testing soft limit.

A dialysis machine (e.g., a peritoneal dialysis (PD) machine) can include a pressure sensor mounted at a proximal end of a patient line that provides PD solution to a patient through a catheter. During treatment, an occlusion can occur at different locations in the patient line and/or the catheter. Elastic waves may be generated at a pump that introduces (e.g., for fill cycles) or withdraws (e.g., for drain cycles) the solution into/out of the patient line. For example, when the solution is introduced or withdrawn suddenly, elastic waves travel distally down the patient line until they encounter the occlusion, and are then reflected back (e.g., toward the pressure sensor).

Disclosed are example embodiments of a dialysis machine having a frame, a cartridge cassette, one or more alignment-locking features, and an actuation mechanism. The frame is fixedly coupled to the dialysis machine, and the cassette is slidably coupled to the frame. The cassette can have one or more track structures, with each of the one or more track structures having a rotor and one or more rollers. The one or more alignment-locking features extend from the frame and are configured to be inserted into one or more alignment features of a disposable cartridge that functions to secure or release the disposable cartridge. The actuation mechanism is made to slide the cassette with respect to the one or more track structures.

A dialysis machine (e.g., a peritoneal dialysis (PD) machine) can include a safety feature that enables the dialysis machine to automatically identify the connections made by a user in preparation for treatment. A smart connector is disclosed that uses a split RFID device that is operational when a first portion of the connector is mated to a second portion of the connector, and is not operational when the first portion is disconnected from the second portion. In an embodiment, the split RFID device incorporates an RFID chip in the first portion of the connector and an antenna in the second portion of the connector. In an embodiment, the RFID chip can store a tag that encodes information that indicates a formulation or a volume of a dialysis bag connected to the ports of a disposable cassette such that the dialysis machine can automatically discover the configuration of the dialysis setup.