DIALYSIS SYSTEM AND METHODS
Dialysis systems and methods are described which can include a number of features. The dialysis systems described can be to provide dialysis therapy to a patient in the comfort of their own home. The dialysis system can be configured to prepare purified water from a tap water source in real-time that is used for creating a dialysate solution. The dialysis systems described also include features that make it easy for a patient to self-administer therapy. For example, the dialysis systems include disposable cartridge and patient tubing sets that are easily installed on the dialysis system and automatically align the tubing set, sensors, venous drip chamber, and other features with the corresponding components on the dialysis system. Methods of use are also provided, including automated priming sequences, blood return sequences, and dynamic balancing methods for controlling a rate of fluid transfer during different types of dialysis, including hemodialysis, ultrafiltration, and hemodiafiltration.
1 . A method of achieving dynamic balancing with a dialysis system, comprising:
operating a blood pump to move a flow of blood from a patient through a patient tubing set and a blood-side of a dialyzer;
operating a first dialysate pump and a second dialysate pump to move a flow of dialysate through a dialysate-side of the dialyzer;
bypassing the flow of dialysate through the dialysate-side of the dialyzer; and
while the flow of dialysate through the dialysate-side of the dialyzer is bypassed, measuring a dialysate pressure between the first dialysate pump and the second dialysate pump, and adjusting a pump speed of the second dialysate pump until the measured dialysate pressure stabilizes.
2 . The method of claim 1 , further comprising resuming the flow of dialysate through the dialysate-side of the dialyzer.
3 . The method of claim 2 wherein no fluid passes from the blood-side of the dialyzer to the dialysate-side of the dialyzer when the flow of dialysate resumes through the dialysate-side of the dialyzer.
4 . The method of claim 1 wherein the bypassing step further comprises actuating valves in the dialysis system to prevent dialysate flow through the dialysate-side of the dialyzer.
5 . The method of claim 1 wherein an electronic controller of the dialysis system performs the operating, bypassing, measuring, and adjusting steps.
6 . A method of achieving dynamic balancing with a dialysis system, comprising:
operating a blood pump to move a flow of blood from a patient through a patient tubing set and a blood-side of a dialyzer;
measuring a venous pressure of the patient;
operating a first dialysate pump and a second dialysate pump to move a flow of dialysate through a dialysate-side of the dialyzer;
preventing a flow of dialysate from passing through the dialysate-side of the dialyzer;
while the flow of dialysate through the dialysate-side of the dialyzer is prevented, measuring a dialysate pressure between the first dialysate pump and the second dialysate pump, and adjusting a pump speed of the second dialysate pump until the measured dialysate pressure stabilizes;
allowing the flow of dialysate to pass through the dialysate-side of the dialyzer; and
adjusting a pump speed of the second dialysate pump to create a flow imbalance between the first and second dialysate pumps that results in a flow of fluid between the blood-side of the dialyzer and the dialysate-side of the dialyzer to equalize the flow imbalance.
7 . The method of claim 6 , wherein the flow of fluid travels from the blood-side of the dialyzer to the dialysate-side of the dialyzer.
8 . The method of claim 6 , wherein the flow of fluid travels from the dialysate-side of the dialyzer to the blood-side of the dialyzer.
9 . The method of claim 6 , comprising further adjusting the pump speed of the second dialysate pump to calibrate for a pressure loss between the blood-side of the dialyzer and the dialysate-side of the dialyzer.
10 . The method of claim 6 , further comprising repeating the preventing, measuring, and adjusting steps if the measured venous pressure changes by a predetermined threshold.
11 . The method of claim 10 , wherein the predetermined threshold comprises more than 30 mmHg.
12 . The method of claim 6 wherein the bypassing step further comprises actuating valves in the dialysis system to prevent dialysate flow through the dialysate-side of the dialyzer.
13 . The method of claim 6 wherein an electronic controller of the dialysis system performs the operating, bypassing, measuring, and adjusting steps.
14 . The method of claim 6 , wherein the pump speed of the second dialysate pump is adjusted based on a lookup table that determines an optimal pump speed based on the measured venous pressure.
15 . A dialysis system, comprising:
a blood pump configured to move a flow of blood from a patient through a patient tubing set and a blood-side of a dialyzer;
a venous pressure sensor configured to measure a venous pressure of the patient;
a first pump and a second pump configured to control the flow of dialysate through a dialysate-side of the dialyzer;
one or more valves configured to bypass the dialysate-side of the dialyzer to prevent the flow of dialysate from passing through the dialysate-side of the dialyzer;
a dialysate pressure sensor disposed between the first and second pumps and configured to measure a dialysate pressure when the dialysate-side of the dialyzer is bypassed; and
an electronic controller operatively coupled to the blood pump, the venous pressure sensor, the first and second pumps, the one or more valves, and the dialysate pressure sensor, the electronic controller configured to adjust a pump speed of the first and second pumps to create a flow imbalance between the first and second pumps that results in a flow of fluid between the blood-side of the dialyzer and the dialysate-side of the dialyzer to equalize the flow imbalance.
16 . A dialysis system, comprising:
a dialyzer comprising a blood-side and a dialysate-side;
a blood circuit coupled to the blood-side of the dialyzer and further comprising a venous line adapted to be connected to an venous connection site of a patient and an arterial line adapted to be connected to an arterial connection site of the patient;
a blood pump coupled to the blood circuit and configured to move blood from the patient, through the arterial line, through the blood-side of the dialyzer, and through the venous line back into the patient;
a venous pressure sensor coupled to the blood circuit and configured to measure a venous pressure of the patient;
a dialysate circuit coupled to the dialysate-side of the dialyzer and further comprising a dialysate line coupled to a dialysate source;
an actuator coupled to the dialysate circuit, the actuator comprising a first configuration in which dialysate moves through the dialysate-side of the dialyzer and a second configuration in which dialysate is prevented from moving through the dialysate-side of the dialyzer;
a first dialysate pump and a second dialysate pump coupled to the dialysate circuit and configured to move dialysate from the dialysate source, through the dialysate line, and through the dialysate-side of the dialyzer when the actuator is in the first configuration;
a dialysate pressure sensor coupled to the dialysate circuit and configured to measure a pressure of the dialysate between the first dialysate pump and the second dialysate pump;
an electronic controller operatively coupled to the blood pump, the venous pressure sensor, the dialysate pressure sensor, the actuator, the first dialysate pump, and the second dialysate pump, the electronic controller being configured to achieve dynamic balancing of fluid flow across the dialyzer during dialysis therapy by performing the steps of:
adjusting a pump speed of the first dialysate pump to move a flow of dialysate through the dialysate-side of the dialyzer;
controlling the actuator to prevent the flow of dialysate from moving through the dialysate-side of the dialyzer;
receiving the measured dialysate pressure from the dialysate pressure sensor; and
adjusting a pump speed of the second dialysate pump until the measured dialysate pressure stabilizes;
controlling the actuator to allow the flow of dialysate to move through the dialysate-side of the dialyzer; and
adjusting a pump speed of the second dialysate pump to create a flow imbalance between the first and second dialysate pumps that results in a flow of fluid between the blood-side of the dialyzer and the dialysate-side of the dialyzer to equalize the flow imbalance.
17 . The system of claim 16 , wherein the electronic controller is configured to receive the measured venous pressure from the venous pressure sensor, and is configured to repeat the controlling, receiving, and adjusting steps if the measured venous pressure changes by a predetermined threshold.