Dialysis machine
A dialysis machine which monitors the pressure of blood entering and leaving a patient's body using several sensors ( 37, 39 ) and adapts the pressure of a dialysate solution feed to compensate for compliances in the dialysate fluid flow path. As a consequence, better flow balance is maintained throughout dialysis treatment leading to a more uniform removal of waste materials from the blood.
1. A dialysis device comprising:
an arterial blood line for delivering patient blood to a dialyser;
a venous blood line for returning dialysed blood from the dialyser to the patient;
a dialysate distribution pump for pumping fresh dialysate into the dialyser and spent dialysate out of the dialyser, the dialysate distribution pump having an inlet line for delivering fresh dialysate to the dialysate distribution pump;
a pressure sensor in the arterial and/or venous blood line that converts a sensed pressure to a signal representative of pressure in the arterial and/or venous blood line;
a controller that monitors the signal from the sensor in the arterial and/or venous blood line and that is configured to generate at least one control signal in response to the signal from the sensor; and
means for controlling pressure in the inlet line in response to the at least one control signal.
2. The device according to claim 1 , wherein the controlling means comprises at least one clamp that, in response to the at least one control signal, is arranged to apply compression force to tubing at a specific position along a flow path of the fresh dialysate.
3. The device according to claim 1 , wherein the dialysate distribution pump is a flow balance pump for matching volume of dialysate pumped into and out of the dialyser.
4. The device according to claim 3 , wherein the flow balance pump has a first pump chamber for pumping dialysate into the dialyser and a second pump chamber for pumping dialysate out of the dialyser.
5. The device according to claim 4 , wherein the inlet line of the dialysate distribution pump is fluidically connected to the first pump chamber.
6. The device according to claim 4 , wherein the first pump chamber of the flow balance pump has a pump cavity covered by a flexible membrane, and is operable to pump dialysate into the dialyser by actuation of the membrane.
7. The device according to claim 4 , wherein the second pump chamber of the flow balance pump has a pump cavity covered by a flexible membrane, and is operable to pump dialysate out of the dialyser by actuation of the membrane.
8. The device according to claim 4 , wherein the first pump chamber of the flow balance pump has an inlet stroke in which dialysate is drawn from a dialysate supply pump, and an outlet stroke in which dialysate is pumped into the dialyser.
9. The device according to claim 4 , wherein the second pump chamber of the flow balance pump has an inlet stroke in which dialysate is drawn from the dialyser and an outlet stroke in which dialysate is pumped to drain.
10. The device according to claim 1 , wherein the controlling means comprises a dialysate supply pump having an outlet fluidically connected to the inlet line of the dialysate distribution pump, the dialysate supply pump being capable of pumping dialysate into the inlet line of the dialysate distribution pump at a predetermined pumping pressure in response to the at least one control signal.
11. The device according to claim 10 , further comprising a valve in the inlet line of the dialysate distribution pump, the valve being situated fluidically between the dialysate supply pump and the dialysate distribution pump.
12. The device according to claim 11 , wherein the controller controls the predetermined pumping pressure in order to achieve a predetermined valve closure pressure in the inlet line upon closure of the valve.
13. The device according to claim 11 , wherein the controller controls a residual pressure in the inlet line of the dialysate distribution pump after completion of an outlet stroke of the dialysate distribution pump in order to achieve a predetermined valve closure pressure in the inlet line upon closure of the valve.
14. The device according to claim 10 , wherein the dialysate supply pump is a membrane pump having a pump cavity covered by a flexible membrane, wherein the dialysate supply pump is operable by actuation of the membrane.
15. The device according to claim 14 , wherein the dialysate supply pump is pneumatically actuable.
16. The device according to claim 15 , wherein the predetermined pumping pressure is controlled by altering a pneumatic pressure applied to the flexible membrane to actuate the dialysate supply pump.
17. The device according to claim 14 , wherein a predetermined residual pressure in the inlet line is controlled by altering a pneumatic pressure applied to the flexible membrane after completion of an outlet stroke of the dialysate supply pump.
18. The device according to claim 10 , wherein the dialysate supply pump has an inlet stroke in which dialysate is drawn into the dialysate supply pump from a dialysate supply, and an outlet stroke in which dialysate is pumped into the inlet line of the dialysate distribution pump.
19. The device according to claim 10 , wherein the controlling means further comprises at least one valve that is arranged to open and close in a dialysate flow path in response to the at least one control signal.
20. The device according to claim 19 , wherein the at least one valve comprises at least one of a dialyser inlet valve, a dialyser outlet valve, a dialysate distribution pump inlet valve, and a dialysate distribution pump outlet valve.
21. The device according to claim 1 , wherein the pressure sensor is situated in the arterial blood line downstream of a blood pump for pumping blood from the patient to the dialyser.
22. The device according to claim 1 , wherein the pressure sensor is situated in the venous blood line.
23. The device according to claim 1 , wherein the controlling means comprises a dialysate distribution pump inlet valve that controls pressure in the inlet line by opening and closing in response to the at least one control signal.
24. A method of operating a dialysis machine which has an arterial blood line for delivering patient blood to a dialyser, a venous blood line for returning dialysed blood from the dialyser to the patient, and a dialysate distribution pump for pumping fresh dialysate into the dialyser and spent dialysate out of the dialyser, the dialysate distribution pump having an inlet line for delivering fresh dialysate to the dialysate distribution pump, the method comprising:
converting a sensed pressure to a signal representative of pressure of blood in the arterial blood line and/or pressure of blood in the venous line;
generating at least one control signal in response to the signal representative of the pressure of blood in the arterial blood line and/or the pressure of blood in the venous blood line; and
step for controlling pressure in the inlet line in response to the at least one control signal.
25. The method according to claim 24 , wherein the dialysate distribution pump is a flow balance pump for matching volume of dialysate pumped into and out of the dialyser.
26. The method according to claim 25 , wherein the flow balance pump has a first pump chamber for pumping dialysate into the dialyser and a second pump chamber for pumping dialysate out of the dialyser.
27. The method according to claim 26 , wherein the inlet line of the dialysate distribution pump is fluidically connected to the first pump chamber.
28. The method according to claim 26 , wherein the first pump chamber of the flow balance pump has a pump cavity covered by a flexible membrane, and is operable by actuation of the membrane.
29. The method according to claim 26 , wherein the second pump chamber of the flow balance pump has a pump cavity covered by a flexible membrane, wherein the pump is operable by actuation of the membrane.
30. The method according to claim 26 , wherein the first pump chamber of the flow balance pump has an inlet stroke in which dialysate is drawn from a dialysate supply pump, and an outlet stroke in which dialysate is pumped into the dialyser.
31. The method according to claim 26 , wherein the second pump chamber of the flow balance pump has an inlet stroke in which dialysate is drawn from the dialyser and an outlet stroke in which dialysate is pumped to drain.
32. The method according to claim 24 , wherein
the dialysis machine further comprises a dialysate supply pump having an outlet fluidically connected to the inlet line of the dialysate distribution pump; and
the controlling step comprises the dialysate supply pump pumping dialysate into the inlet line of the dialysate distribution pump at a predetermined pumping pressure in response to the at least one control signal.
33. The method according to claim 32 , wherein the dialysis machine further comprises a valve in the inlet line of the dialysate distribution pump, the valve being situated fluidically between the dialysate supply pump and the dialysate distribution pump.
34. The method according to claim 33 , wherein the controlling step further comprises controlling the predetermined pumping pressure in order to achieve a predetermined valve closure pressure in the inlet line upon closure of the valve.
35. The method according to claim 33 , wherein the controlling step further comprises controlling a residual pressure in the inlet line of the dialysate distribution pump after completion of an outlet stroke of the dialysate distribution pump in order to achieve a predetermined valve closure pressure in the inlet line upon, before, or at a same time as closure of the valve.
36. The method according to claim 32 , wherein the dialysate supply pump has an inlet stroke in which dialysate is drawn into the dialysate supply pump from a dialysate supply, and an outlet stroke in which dialysate is pumped into the inlet line of the dialysate distribution pump.
37. The method according to claim 32 , wherein the controlling step further comprises controlling the predetermined pumping pressure by setting a pneumatic pressure applied to a flexible membrane to actuate the dialysate supply pump.
38. The method according to claim 32 , wherein the controlling step further comprises controlling a predetermined residual pressure in the inlet line by setting a pneumatic pressure applied to a flexible membrane after completion of an outlet stroke of the dialysate supply pump.
39. The method according to claim 32 , wherein the controlling step further comprises operating at least one valve in a dialysate flow path in response to the at least one control signal.
40. The method according to claim 39 , wherein the at least one valve comprises at least one of a dialyser inlet valve, a dialyser outlet valve, a dialysate distribution pump inlet valve, and a dialysate distribution pump outlet valve.
41. The method according to claim 24 , wherein the controlling step comprises operating a dialysate distribution pump valve in response to the at least one control signal.
42. The method according to claim 24 , wherein the controlling step comprises at least one clamp applying compression force to tubing at a specific position along a flow path of the fresh dialysate in response to the at least one control signal.
43. A computer program product embodied on a tangible computer readable storage medium which, when executed by a controller in communication with components of a dialysis machine, causes the controller to generate at least one control signal in response to a signal representative of pressure sensed in an arterial blood line and/or a venous blood line of the dialysis machine;
wherein the arterial blood line is for delivering patient blood to a dialyser of the dialysis machine, and the venous blood line is for returning dialysed blood from the dialyser to the patient;
wherein the dialysis machine comprises a dialysate distribution pump for pumping fresh dialysate into the dialyser and spent dialysate out of the dialyser, the dialysate distribution pump having an inlet line for delivering fresh dialysate to the dialysate distribution pump;
wherein the dialysis machine performs a step for controlling pressure in the inlet line in response to the at least one control signal; and
wherein the components of the dialysis machine in communication with the controller comprise one or more components that perform the step for controlling pressure in the inlet line and to which the controller sends the at least one control signal, and comprise one or more components from which the controller receives the signal representative of pressure sensed in the arterial blood line and/or the venous blood line.