Peritoneal dialysis using pressurized cylinder

1. A peritoneal dialysis system comprising:

a pump housing;

a cylinder in pneumatic communication with the pump housing;

a piston including a piston head slidably sealed within the cylinder;

a linear actuator in mechanical communication with the piston;

a pressure sensor positioned and arranged to sense a pressure within the pump housing caused by movement of the piston within the cylinder;

a fluid inlet valve;

a fluid outlet valve;

a fluid pump chamber including a flexible membrane moved by the pressure within the pump housing when the fluid pump chamber is sealed to the pump housing;

a fluid inlet line and a fluid outlet line in fluid communication with the fluid pump chamber; and

a control unit configured to cause (i) the fluid inlet valve and the fluid outlet valve to occlude the fluid inlet line and the fluid outlet line, respectively, while the linear actuator moves the piston to create a positive pressure within the pump housing, the positive pressure measured by the pressure sensor, and (ii) the fluid inlet valve to occlude the fluid inlet line and the fluid outlet valve to open the fluid outlet line, while the linear actuator moves the piston so as to maintain the positive pressure within the pump housing while fluid is pumped out of the fluid pump chamber via the opened fluid outlet line.

2. The peritoneal dialysis system of claim 1 , wherein the control unit is further configured to cause, prior to (i), the fluid inlet valve to open the fluid inlet line and the fluid outlet valve to occlude the fluid outlet line, while the linear actuator moves the piston so as to create a negative pressure within the cylinder to pull fluid into the fluid pump chamber via the opened fluid inlet line.

3. The peritoneal dialysis system of claim 2 , wherein the negative pressure is measured by the pressure sensor, the control unit operable with the pressure sensor and configured to stop the linear actuator when the negative pressure reaches a commanded pressure.

4. The peritoneal dialysis system of claim 1 , wherein the control unit is further configured to use a measured distance that the piston is moved during (ii) to perform a calculation of a volume of the fluid pumped out of the fluid pump chamber via the opened fluid outlet line.

5. The peritoneal dialysis system of claim 4 , wherein the calculation assumes the same positive pressure exists at the end of both (i) and (ii).

6. The peritoneal dialysis system of claim 4 , wherein the calculation of the volume includes at least one dimension of the cylinder.

7. The peritoneal dialysis system of claim 4 , wherein the linear actuator includes a position detection mechanism to provide the measured distance to the control unit.

8. The peritoneal dialysis system of claim 4 , wherein the control unit is further configured to add a plurality of the volumes of the fluid pumped out of the fluid pump chamber to determine a total volume of fluid pumped from the fluid pump chamber to a destination.

9. The peritoneal dialysis system of claim 8 , wherein the destination includes a patient catheter, a heating container or a drain location.

10. The peritoneal dialysis system of claim 8 , wherein the control unit is further configured to perform a pressure adjustment within the fluid pump chamber after (ii).

11. The peritoneal dialysis system of claim 8 , wherein the source includes a patient catheter, a heating container or a fluid supply.

12. The peritoneal dialysis system of claim 1 , wherein maintaining the positive pressure within the pump housing while fluid is pumped out of the fluid pump chamber includes (a) reestablishing the positive pressure after the positive pressure is initially lowered in (ii) or (b) holding the positive pressure at least substantially constant.

13. The peritoneal dialysis system of claim 1 , wherein the control unit is further configured to cause, during at least one of (i) or (ii), a second fluid inlet valve to open a second fluid inlet line and a second fluid outlet valve to occlude a second fluid outlet line, while a second linear actuator moves a second piston so as to create a negative pressure within a second cylinder to pull fluid into a second fluid pump chamber via the opened second fluid inlet line.

14. The peritoneal dialysis system of claim 1 , wherein at least one of (i) the inlet valve is a fluid supply line valve, a heater line valve or a patient line valve, or (ii) the outlet valve is the patient line valve, the heater line valve or a drain line valve.

15. A peritoneal dialysis system comprising:

a cycler including

a pump housing,

a linear actuator,

a pressure sensor positioned and arranged to sense a pressure within the pump housing caused by movement of the linear actuator,

a fluid inlet valve, and

a fluid outlet valve:

a disposable set including

a fluid pump chamber including a flexible membrane moved by the pressure within the pump housing when the fluid pump chamber is sealed to the pump housing, and

a fluid inlet line and a fluid outlet line in fluid communication with the fluid pump chamber; and

a control unit configured to cause (i) the fluid inlet valve and the fluid outlet valve to occlude the fluid inlet line and the fluid outlet line, respectively, while the linear actuator creates a positive pressure within the pump housing, the positive pressure measured by the pressure sensor, and (ii) the fluid inlet valve to occlude the fluid inlet line and the fluid outlet valve to open the fluid outlet line, while the linear actuator maintains the positive pressure within the pump housing and fluid is pumped out of the fluid pump chamber via the opened fluid outlet line.

16. The peritoneal dialysis system of claim 15 , wherein maintaining the positive pressure within the pump housing while fluid is pumped out of the fluid pump chamber includes (a) reestablishing the positive pressure after the positive pressure is initially lowered in (ii) or (b) holding the positive pressure at least substantially constant.

17. The peritoneal dialysis system of claim 15 , wherein the cycler further includes a cylinder in pneumatic communication with the pump housing, a piston including a piston head slidably sealed within the cylinder, the linear actuator in mechanical communication with the piston, and wherein the linear actuator moves the piston in (i) and (ii) to create and maintain the positive pressure.

18. The peritoneal dialysis system of claim 15 , wherein the linear actuator includes a motor in mechanical communication with a rotational to translational conversion apparatus.

19. The peritoneal dialysis system of claim 15 , wherein the fluid inlet valve and fluid outlet valve are pinch valves positioned and arranged to pinch or open the fluid inlet line and fluid outlet line, respectively.

20. The peritoneal dialysis system of claim 15 , wherein the disposable set further includes at least one of a patient line, supply line, heater line or drain line in fluid communication with at least one of the fluid inlet line or fluid outlet line.

21. The peritoneal dialysis system of claim 20 , wherein the cycler further includes at least one of a patient line valve for allowing or occluding flow through the patient line, a supply line valve for allowing or occluding flow through the supply line, a heater line valve for allowing or occluding flow through the heater line, or a drain line valve for allowing or occluding flow through the drain line.

22. The peritoneal dialysis system of claim 20 , wherein at least one of (i) the fluid inlet line is a fluid supply line, a heater line or a patient line, or (ii) the fluid outlet line is the patient line, the heater line or a drain line.