NxStage Medical, Inc.

A blood treatment system with pressure sensors may be configured to control blood flow to and from the patient and use readings of the pressure sensors to determine a change in a pressure drop across a flow restriction in the blood circuit to estimate a condition of the machine or the patient, or outputting data responsive to the estimation. Further embodiments employ measurement of pressure drop to detect abnormal viscosity or viscosity variations in order to detect possible infection.

A method of reducing leakage current from a patient to a ground potential through an applied part of a medical device includes defining a maximum permissible leakage current A max from the patient to the ground potential when the patient is energized to an electric potential V and supplying the medical device with water having a resistivity value p through a fluid line having a length L and an inner diameter ID. The value of L and ID is selected to cause the fluid conduit filled with water of resistivity ρ to have a resistance of R high enough to maintain the leakage current from the patient to the ground potential below A max .

A flow restrictor includes a flexible tube held in a housing and a linear actuator connected through an intermediate link to a distal link via a first revolute joint proximate the linear actuator and a second revolute joint connecting the intermediate and distal links. The distal link has a distal end adjacent the flexible tube and the intermediate and distal links are constrained to move such that when the linear actuator moves the first revolute joint toward the linear actuator, the distal end of the distal link is driven into the side of the tube thereby progressively occluding the flexible tube.

A proportioning system includes a solute container filled with dry solutes, a source of water, a container of electrolyte concentrate, a fluid circuit connecting the solute container to the source of water and the container of electrolyte concentrate, the fluid circuit having an empty mixing container, a controller configured to transfer water from the source of water to the solute container through the fluid circuit so as to prepare a solute concentrate solution in the solute container. The controller is configured to transfer fluid from the container of electrolyte concentrate to a mixing container as well as a solute concentrate from the solute container to the mixing container and further adding water to said mixing container to form a medicament therein.

A pressure measurement system includes a pressure pod with two chambers separated by a diaphragm such that a deformation/movement of the diaphragm is indicative of a difference between the pressures of the two chambers. Such deformation/movement is detected by a device that has no physical contact with the diaphragm, for example, by an optical detector that detects a change in the shape of the diaphragm or a movement of a protrusion on the diaphragm.

A proportioning device includes a proportioning machine with a temperature-compensating conductivity sensor, a controller, and pump actuator. A fluid circuit is engageable with the pump actuator, has connections for a source of water and one or more medicament concentrates, and includes a mixing container. The controller is configured to mix contents of the mixing container at a first time and to sample fluid from the mixing container, to pass the samples from the mixing container through the temperature-compensating conductivity sensor at different points in time as the fluid flows from the mixing container. The controller is further configured to mix contents of the mixing container a second time if the conductivities differ by a predefined magnitude.

A method of reducing leakage current from a patient to a ground potential through an applied part of a medical device includes defining a maximum permissible leakage current A max from the patient to the ground potential when the patient is energized to an electric potential V and supplying the medical device with water having a resistivity value ρ through a fluid line having a length L and an inner diameter ID. The value of L and ID is selected to cause the fluid conduit filled with water of resistivity ρ to have a resistance of R high enough to maintain the leakage current from the patient to the ground potential below A max .

A proportioning system includes a solute container filled with dry solutes, a source of water, a container of electrolyte concentrate, a fluid circuit connecting the solute container to the source of water and the container of electrolyte concentrate, the fluid circuit having an empty mixing container, a controller configured to transfer water from the source of water to the solute container through the fluid circuit so as to prepare a solute concentrate solution in the solute container. The controller is configured to transfer fluid from the container of electrolyte concentrate to a mixing container as well as a solute concentrate from the solute container to the mixing container and further adding water to said mixing container to form a medicament therein.

Methods, device, and systems for preparing peritoneal dialysis fluid and/or administering a peritoneal dialysis treatment are disclosed. In embodiments, peritoneal dialysis fluid is prepared at a point of use automatically using a daily sterile disposable fluid circuit and one or more long-term concentrate containers that are changed only after multiple days (e.g. weekly). The daily disposable may have concentrate containers that are initially empty and are filled from the long-term concentrate containers once per day at the beginning of a treatment.

A system for preparing a medicament for use by a medicament user includes a proportioning machine with a controller and pumping and clamping actuators to engage a fluid circuit having pumping and clamping portions that engage with respective actuators of the proportioning machine. The fluid circuit includes a mixing container that is initially empty and later filled with a concentrated medicament from a concentrate container. The proportioning machine is configured to receive purified water and to mix it with the concentrated medicament to produce a medicament and to output the medicament to a medicament consumer in such a way that to the medicament consumer the medicament appears to be provided from a bag of medicament.