Avoy, Richard (Palm Harbor, FL, US)
Booras, John (Wildwood, IL, US)
Joseph Jr., Bowman H. (Lake Villa, IL, US)
Grippo, Paul (Palm Harbor, FL, US)
Hopping, Andrew D. (Largo, FL, US)
Howard, David (Gulfport, FL, US)
Jerrell, Jeffrey W. (Clearwater, FL, US)
Kellam, Benjamin (Clearwater, FL, US)
Lauman, Brian (Clearwater, FL, US)
Shang, Sherwin (Vernon Hills, IL, US)
Vescovi, David (Pinellas Park, FL, US)
Yang, Tahua (Woodbridge, IL, US)
Yu, Alex (Safety Harbor, FL, US)
Plaque It!
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The invention is claimed as follows:
1. An assembly for operating a dialysis cassette comprising: a housing; a pump actuator in communication with the housing; a flow path defined by the housing; at least one valve coupled to the housing and in communication with the flow path; and an inlet in communication with the flow path.
2. The housing of claim 1, which includes a plurality of inlets in communication with the flow path.
3. The assembly of claim 2, wherein the inlets are placed at opposing ends of the flow path.
4. The assembly of claim 1, wherein the valve is located on a raised portion of the housing, the raised portion covering at least a portion of the flow path.
5. The assembly of claim 1, wherein the housing is constructed at least partially of a material selected from the group consisting of: metal and plastic.
6. The assembly of claim 1, which includes at least one sensor attached to the housing, the sensor selected from the group consisting of: a pressure sensor, a temperature sensor, a fluid volume sensor, a liquid level sensor, an air detection sensor, a bubble sensor, a turbidity sensor, a conductivity sensor, a pH sensor, a chemical sensor, a color detection sensor, and a particle detection sensor.
7. The assembly of claim 1, wherein the housing, beneath each valve, defines an aperture, and wherein valve plungers are positioned on an opposite side of the housing from the valves, the plungers disposed about the apertures.
8. The assembly of claim 1, wherein the valve opens and closes a fluid path from a pneumatic source.
9. The assembly of claim 1, wherein the valve opens and closes a fluid path from atmospheric air.
10. The assembly of claim 1, wherein the valve is activated electrically.
11. The assembly of claim 1, wherein the valve is a three-way valve.
12. The assembly of claim 1, wherein the pump actuator is selected from the group consisting of: a linear motor, rotating motor and a spring.
13. The assembly of claim 1, wherein the flow path is a first flow path, the body defines a second fluid flow path and at least one valve is in communication with the second path.
14. The assembly of claim 13, wherein the first flow path is a vacuum path and the second flow path is an atmospheric path.
15. The assembly of claim 1, which is placed in a machine that performs a dialysis therapy, the therapy selected from the group consisting of: continuous flow peritoneal dialysis, automated peritoneal dialysis, tidal flow peritoneal dialysis, hemofiltration and hemodialysis.
16. The assembly of claim 1, which cooperates with the cassette to automatically align the cassette for operation.
17. A system for operating a dialysis cassette comprising: an assembly including a housing defining a fluid flow path, a pump actuator and a plurality of valves coupled to the housing, the valves in communication with the fluid flow path; a pneumatic source in communication with the fluid flow path; a plurality of valve plungers operable with the valves; and a pump piston operable with the pump actuator.
18. The system of claim 17, wherein the pump actuator is in communication with the pneumatic source.
19. The system of claim 17, which includes a spring operable with each of the valves, and wherein the pneumatic source is a negative pressure source that compresses the springs.
20. The system of claim 17, which includes a spring positioned between each of the valve plungers and the housing.
21. The system of claim 20, wherein the valves in an unenergized state disallow flow from the pneumatic source so that the springs push the valve plungers to close at least one flow path in the dialysis cassette.
22. The system of claim 17, which includes a second fluid path that, through at least one of the valves, communicates with ambient air.
23. The system of claim 17, wherein the valves in an unenergized state are open to ambient air and closed to the pneumatic pressure source.
24. The system of claim 17, wherein the assembly includes at least one plate that couples to the housing, the plate housing at least a portion of the valve plungers.
25. A system for performing dialysis comprising: a patient line; a disposable cassette in communication with the patient line; and an assembly connected operably to the disposable cassette, the assembly including a housing defining a fluid flow path and a plurality of valves in communication with the fluid path.
26. The system of claim 25, which includes a pump actuator in communication with a pumping portion of the cassette.
27. The system of claim 25, wherein the valves are in communication with valve portions of the cassette.
28. The system of claim 25, wherein the cassette includes a fluid heating pathway, and which includes a gas separation chamber downstream of the heating pathway.
29. A system for performing dialysis comprising: a housing; a negative pressure source in communication with housing; and a plurality of values coupled to the housing and communicating with the negative pressure source.
30. The system of claim 29, which includes a pump actuator coupled to the housing.
31. The system of claim 29, wherein at least one of: the valves and the pump actuator operates with a spring.
32. The system of claim 29, wherein the valves move valve plungers to contact a membrane made of a material that includes a polyolefin.
33. A medical fluid pump comprising: a pump piston having a piston head; a flexible membrane that moves to pump medical fluid; a spring biased to push the piston head toward the flexible membrane; and a diaphragm that moves with the piston and enables negative pressure to be applied that compresses the spring.
34. The medical fluid pump of claim 33, wherein the diaphragm is sealingly coupled to the piston.
35. The medical fluid pump of claim 33, wherein the spring is coupled to the piston and moves the piston when compressed.
36. The medical fluid pump of claim 35, which uses negative pressure to draw the membrane toward the piston head when compressing the spring and moving the piston.
37. The medical fluid pump of claim 33, wherein the spring is disposed in a cavity, the cavity is defined at least partially by the diaphragm and the negative pressure is applied to the cavity.
38. The medical fluid pump of claim 33, wherein the negative pressure is applied at a first level to compress the spring and at a second level when the spring biases the piston head towards the membrane to hold the diaphragm in a desired position.
39. The medical fluid pump of claim 38, wherein the second vacuum level is less than the first vacuum level.
40. The medical fluid pump of claim 33, wherein the membrane is attached to a rigid portion of a disposable cassette and the fluid is pumped between the membrane and the rigid portion.
41. The medical fluid pump of claim 40, wherein the spring biases the membrane towards the rigid portion.
42. The medical fluid pump of claim 33, wherein the diaphragm is a first diaphragm and which includes a second diaphragm that moves with the piston and enables negative pressure to be applied between the piston head and the membrane.
43. The medical fluid pump of claim 42, wherein the second diaphragm is coupled sealingly to the piston.
44. The medical fluid pump of claim 42, wherein the negative pressure applied between the piston head and the membrane holds the second diaphragm in a desired orientation as the piston moves.
45. The medical fluid pump of claim 42, which includes a space between the first and second diaphragms, the space maintained at atmospheric or positive pressure.
46. The medical fluid pump of claim 42, wherein the negative pressure is applied to the first diaphragm at a first level to compress the spring and at a second level when the spring biases the piston head towards the membrane to hold the first diaphragm in a desired position.
47. The medical fluid pump of claim 33, wherein the negative pressure is applied cooperatively to compress the spring and pull the membrane to the piston head.
48. The medical fluid pump of claim 47, which includes a plurality of negative pressure sources that apply the cooperative negative pressures.
49. A medical fluid pump comprising: a flexible membrane that is moveable to pump medical fluid; a cylinder; a spring-loaded piston disposed inside the cylinder, the piston having a base at one end and piston head at the other end, the spring biased to push the head toward the membrane; and a pressure source that applies pressure within the cylinder to compress the spring.
50. The medical fluid pump of claim 49, wherein the pressure is a negative pressure applied at the base to compress the spring.
51. The medical fluid pump of claim 50, wherein negative pressure is applied additionally to draw the membrane toward the piston head when compressing the spring and moving the piston.
52. The medical fluid pump of claim 49, wherein the pressure is a positive pressure applied near the piston head end of the piston to compress the spring.
53. The medical fluid pump of claim 52, which includes a negative pressure source that applies a negative pressure to draw the membrane toward the piston head when compressing the spring and moving the piston.
54. A medical fluid valve comprising: a valve plunger; a flexible membrane that moves to allow and restrict fluid flow; a spring biased to push the plunger toward the flexible membrane; and a diaphragm that moves with the plunger and enables a negative pressure to be applied that compresses the spring.
55. The medical fluid valve of claim 54, wherein the plunger includes a compliant member to aid in sealing the plunger to the membrane.
56. The medical fluid valve of claim 54, wherein the diaphragm is coupled sealingly to the plunger.
57. The medical fluid valve of claim 54, wherein the spring is disposed in a chamber, the chamber defined at least partially by the diaphragm, the negative pressure applied to the chamber.
58. The medical fluid valve of claim 54, wherein the spring is coupled to the plunger and moves the plunger when compressed.
59. The medical fluid valve of claim 54, wherein negative pressure is applied additionally to draw the membrane toward the plunger when compressing the spring and moving the plunger.
60. The medical fluid valve of claim 59, wherein the negative pressure is applied at a different magnitude to compress the spring than to draw the membrane.
61. The medical fluid valve of claim 54, wherein the membrane is attached to a rigid portion of a disposable, the membrane, when pulled away from the rigid portion, creating a fluid pathway between apertures defined by the portion.
62. The medical fluid valve of claim 54, wherein the membrane is made of a material including a polyolefin.
63. A system for performing dialysis comprising: a patient line; a disposable cassette in communication with the patient line; a pump spring biasing a pump head to contact a pumping portion of the cassette; a valve spring biasing a valve plunger to contact a value portion of the cassette; and a source that applies negative pressure to compress the pump spring and valve spring, allowing fluid to be pumped through the pumping portion and to flow through the valve portion of the cassette.
64. The system of claim 63, wherein negative pressure is applied additionally to draw a membrane of the cassette toward the pump head and valve plunger when compressing the springs.
65. The system of claim 63, which includes at least one diaphragm that creates at least in part a sealed vacuum chamber for the pump and valve springs.
66. The system of claim 63, which includes a plurality of spring-loaded pump heads contacting the cassette.
67. The system of claim 63, which includes a plurality of the valve plungers contacting the cassette.
68. The system of claim 63, which includes a plurality of membranes attached to opposing sides of the cassette and at least one valve plunger communicating with each membrane.
69. The system of claim 63, wherein the disposable cassette is in fluid communication with at least one of: a fluid supply and a fluid regeneration line.
70. The system of claim 63, which performs a dialysis therapy selected from the group consisting of: continuous flow peritoneal dialysis, automated peritoneal dialysis, tidal flow peritoneal dialysis, hemofiltration and hemodialysis.
71. The system of claim 63, wherein the pumping portion of the cassette communicates with at least two fluid sources.
72. The system of claim 63, wherein the pumping portion of the cassette communicates with at least two fluid destinations.
73. The system of claim 63, wherein the pump head automatically aligns the cassette before pumping begins.
74. The system of claim 63, wherein the cassette includes an integrally formed port vent.
75. The system of claim 63, which controls the valve plunger so that only one fluid flows through the pumping portion at one time.
76. The system of claim 63, which controls the pump spring so that it extends fully on each pump stroke.
77. A method for performing dialysis comprising the steps of: (a) releasing a first spring biased to cause a pump chamber to decrease in volume and expel fluid; (b) releasing a second spring biased to cause an inlet valve to close; and (c) applying negative pressure to compress a third spring to cause an outlet valve to open so that the fluid expelled from the pump chamber can flow to a patient.
78. The method of claim 77, which includes applying negative pressure additionally to cause a flexible membrane to move and the outlet valve to open.
79. The method of claim 77, which includes applying a negative pressure to a vacuum chamber housing the first spring to hold a diaphragm in a desired configuration.
80. The method of claim 77, which includes disposing a least one of the outlet valves on a same housing with a pump actuator operable with the pump chamber.
81. The method of claim 77, which includes the further steps of: (d) releasing the third spring, which is biased to cause the outlet valve to close; and (e) applying negative pressure to compress the first and second springs to cause the pump chamber volume to increase and fill with fluid and the inlet valve to open so fluid can be supplied to the chamber.
82. The method of claim 81, which includes applying negative pressure additionally to cause a flexible membrane to move, the pump chamber volume to increase and the inlet valve to open.
83. The method of claim 81, wherein the pump chamber, inlet valves and outlet valves are a first pump chamber, first inlet valve and first outlet valve, which includes a second pump chamber and second inlet and outlet valves connected fluidly, and which includes performing steps (a) to (c) for the second pump chamber and second valves while performing steps (d) and (e) for the first pump chamber and first valves.
84. The method of claim 83, which includes performing steps (d) and (e) for the second pump chamber and second valves while performing steps (a) to (c) for the first pump chamber and first valves.
85. The method of claim 83, wherein the first and second pump chambers operate according to a pumping schedule based on at least one pumping rule stored in software.
86. A method for aligning a disposable cassette within a dialysis machine comprising the steps of: actuating a pump head toward the disposable cassette and shifting a pumping portion of the disposable cassette to be aligned with the head; and locking the disposable in place.
87. The method of claim 86, wherein actuating the pump head includes moving a pump piston.
88. The method of claim 86, which includes actuating a plurality of pump heads toward the disposable cassette.
89. The method of claim 86, wherein actuating the pump head includes using a positive or negative pressure source.
90. The method of claim 86, which includes the step of locking a door and enclosing the disposable cassette before actuating the pump head.
91. The method of claim 86, wherein the pumping portion of the disposable cassette includes at least one flexible membrane.
92. The method of claim 86, wherein locking the disposable cassette in place includes moving a member mechanically.
93. The method of claim 86, wherein locking the disposable cassette in place includes inflating a bladder.
94. The method of claim 86, which includes the step of sensing a resistance to movement of the pump head caused by the disposable cassette and causing a response based on the resistance.
95. The method of claim 94, wherein the response is selected from the group consisting of: an output to proceed with the therapy, a disposable cassette misalignment output and a disposable cassette integrity problem output.
96. A method for detecting an integrity problem with a disposable cassette misalignment in a dialysis machine comprising the steps of: actuating a pump head toward the disposable cassette; and sensing a resistance to movement of the pump head caused by the disposable cassette.
97. The method of claim 96, which includes the step of sending a disposable cassette misalignment error message to a patient.
98. The method of claim 96, which includes the step of comparing the resistance sensed to a resistance expected and sending the disposable cassette misalignment output based on the resistance sensed and the comparison.
99. A method for diagnosing an integrity problem with a disposable cassette used in a dialysis machine comprising the steps of: actuating a pump head toward the disposable cassette; sensing a resistance to movement of the pump head caused by the disposable cassette; and sending a disposable cassette integrity problem output based on the resistance sensed.
100. The method of claim 99, which includes sending a disposable cassette integrity problem error message to a patient.
101. The method of claim 99, which includes the step of comparing the resistance sensed to a resistance expected and sending the disposable cassette integrity problem output based on the resistance sensed and the comparison.
102. A system for performing a dialysis treatment comprising: a patient line; a pump that pumps fluid to the patient line, the pump including a flexible portion of a disposable cassette; and a controller connected operably to the pump, the controller before locking the disposable cassette so that fluid can be pumped causing a pump head to contact and move the flexible portion into alignment with respect to the pump head.
103. The system of claim 102, wherein the patient line is a fill line and which includes a return patient line that returns fluid from a patient to a regeneration device.
104. The system of claim 102, which includes a plurality of flexible pump disposable cassette portions and pump heads, the program commanding the pump heads before locking the disposable to contact and move, if needed, respective flexible pumping portions.
105. The system of claim 102, which includes a display device connected operably to the controller and a message displayed by the display device, the message based on a resistance by the flexible portion to movement of the pump head.
106. The system of claim 102, wherein the treatment is selected from the group consisting of: continuous flow peritoneal dialysis, tidal flow peritoneal dialysis, automated peritoneal dialysis, hemodialysis and hemofiltration.
107. The system of claim 102, wherein the pump includes a pump spring that is moved via positive or negative pressure.
108. The system of claim 107, which includes at least one additional fluid line connected fluidly to the pump selected from the group consisting of: a regeneration line, a dialysate supply line, a concentrate additive line, an ultrafiltrate line and a drain line.
109. The system of claim 107, wherein the controller applies at least one pumping rule to control the pumping of the pump.
110. A fluid pumping mechanism comprising; a fluid reservoir; and a monolayer film extending over a portion of the fluid reservoir, wherein fluid is moved through the reservoir by movement of the film from a first position to a second position, the film including a first polyolefin.
111. The mechanism of claim 110, wherein the first polyolefin is selected from the group consisting of homopolymers and copolymers obtained by polymerizing a first alpha-olefin containing from 2 to 20 carbon atoms.
112. The mechanism of claim 110, wherein the first polyolefin is selected from ethylene homopolymers and ethylene copolymers.
113. The mechanism of claim 112, wherein the ethylene copolymer is an ethylene and second alpha-olefin copolymer.
114. The mechanism of claim 113, wherein the second alpha-olefin has from 4 to 8 carbons.
115. The mechanism of claim 114, wherein the ethylene and second alpha-olefin copolymer has a density less than 0.915 g/cc.
116. The mechanism of claim 114, wherein the ethylene and second alpha-olefin copolymer has a density less than 0.910 g/cc.
117. The mechanism of claim 114, wherein the ethylene and second alpha-olefin copolymer has a density less than 0.905 g/cc.
118. The mechanism of claim 112, wherein the ethylene copolymer is a copolymer of ethylene with a comonomer selected from the group of lower alkyl acrylates, lower alkyl substituted alkyl acrylates and vinyl acetate.
119. The mechanism of claim 111, wherein the first polyolefin is selected from the group consisting of propylene homopolymers and propylene copolymers.
120. The mechanism of claim 111, wherein the fluid reservoir is defined by a pumping cassette.
121. The mechanism of claim 110, wherein the film is capable of being sterilized by gamma irradiation or ethylene oxide sterilization.
122. The mechanism of claim 110, wherein the film is thermoformed.
123. The mechanism of claim 110, wherein the film has an elongation of from about 5% to about 40%.
124. The mechanism of claim 110, wherein the film has a portion domed.
125. The mechanism of claim 110, wherein the film has a modulus of elasticity of less than 20,000 psi.
126. The mechanism of claim 110, wherein the film is capable of being deformed by a piston to move fluid through the reservoir at a rate that will not vary from the first stroke to the 10,000
127. The mechanism of claim 110, wherein the film has a heat transfer coefficient of greater than 0.20 Watts/minute-Kelvin for a film having a thickness of 5 mils.
128. The mechanism of claim 110, wherein the film has a textured finish.
129. The mechanism of claim 110, wherein the film has a substantially constant modulus of elasticity over a temperature range of from 5-40° C.
130. The mechanism of claim 110, wherein the film is moved from a first position to a second position with a plunger and wherein the plunger does not stick to the film.
131. The mechanism of claim 120, wherein the pumping cassette is fabricated from a first polymer selected from the group consisting of homopolymer and copolymers of cyclic olefin containing polymers and homopolymers and copolymers of bridged polycylic hydrocarbon containing polymers.
132. The mechanism of claim 131, wherein the cassette is selected from homopolymers and copolymers of norbornene.
133. The mechanism of claim 132, wherein the pumping cassette is a copolymer of norbornene and a third alpha-olefin.
134. The mechanism of claim 133, wherein the third alpha-olefin is ethylene.
135. The mechanism of claim 134, wherein the cassette is fabricated from a polymer blend of a first component of a norbornene and ethylene copolymer and a second component of an ethylene and fourth alpha-olefin copolymer.
136. The mechanism of claim 135, wherein the fourth alpha-olefin has from 4 to 8 carbons.
137. The mechanism of claim 136, wherein the fourth alpha-olefin has 6 carbons.
138. The mechanism of claim 135, wherein the first component is present in an amount by weight of from 30% to about 99% by weight of the blend and the second component is present in an amount from 1% to about 70% by weight of the blend.
139. The mechanism of claim 110, further comprising a tubing in fluid communication with the fluid reservoir.
140. The mechanism of claim 139, wherein the tubing is fabricated from a second polyolefin.
141. The mechanism of claim 140, wherein the second polyolefin is selected from the group consisting of homopolymers and copolymers obtained by polymerizing a fifth alpha-olefin containing from 2 to 20 carbon atoms.
142. The mechanism of claim 141, wherein the second polyolefin is selected from ethylene homopolymers and ethylene copolymers.
143. The mechanism of claim 142, wherein the ethylene copolymer is an ethylene and sixth alpha-olefin copolymer.
144. The mechanism of claim 143, wherein the sixth alpha-olefin has from 4 to 8 carbons.
145. The mechanism of claim 143, wherein the ethylene and sixth alpha-olefin copolymer is obtained using a metallocene catalyst.
146. The mechanism of claim 142, wherein the second polyolefin is a blend of polyolefin polymers.
147. The mechanism of claim 146, wherein the second polyolefin is a blend of two m-ULDPE resins.
148. The mechanism of claim 146, wherein the second polyolefin is a blend of three m-ULDPE resins.
149. The mechanism of claim 139, wherein the tubing is fabricated from a material having a density less than 0.915 g/cc.
150. The mechanism of claim 139, wherein the tubing is formed by an extrusion process.
151. The mechanism of claim 139, wherein the tubing is capable of being sterilized by gamma irradiation or ethylene oxide sterilization.
152. The mechanism of claim 110, which is used in a therapy selected from the group consisting of: continuous flow peritoneal dialysis, automated peritoneal dialysis, tidal flow peritoneal dialysis, hemofiltration and hemodialysis.
153. A fluid pumping mechanism comprising; a fluid reservoir; and a multiple layer film extending over a portion of the fluid reservoir, wherein fluid is moved through the reservoir by movement of the film from a first position to a second position, the film including an inner layer and an outer layer, the inner layer including an ethylene containing polymer.
154. The mechanism of claim 153, wherein the inner layer is an ethylene homopolymer or an ethylene copolymer.
155. The mechanism of claim 154, wherein the inner layer is an ethylene alpha-olefin copolymer having a density less than 0.915 g/cc.
156. The mechanism of claim 155, wherein the outer layer is a polymer, metal foil or paper.
157. The mechanism of claim 153, wherein the fluid reservoir is defined by a frame and the film is attached to the frame.
158. The mechanism of claim 157, wherein the film is attached to the frame by heat sealing.
159. The mechanism of claim 153, further comprising a tubing in fluid communication with the reservoir.
160. The mechanism of claim 159, wherein the reservoir is defined by a frame and the tubing is connected to the frame by solvent bonding.
161. The mechanism of claim 153, which is used in a therapy selected from the group consisting of: continuous flow peritoneal dialysis, automated peritoneal dialysis, tidal flow peritoneal dialysis, hemofiltration and hemodialysis.
162. A system for performing a dialysis treatment comprising: a fluid pump; first and second inlet paths in communication with the fluid pump; first and second fluids flowing within the first and second inlet paths respectively; first and second intake valves communicating respectively with the first and second inlet paths; first and second outlet paths in communication with the fluid pump; first and second exhaust valves communicating respectively with the first and second outlet paths; and a controller that sequentially opens the valves to control the proportion of the first and second fluids being pumped.
163. The system of claim 162, wherein the controller controls additionally the proportion of fluid flowing through the first and second outlet paths.
164. The system of claim 162, which includes a disposable cassette having a rigid portion, at least one flexible membrane attached to the rigid portion, the pump operable with the membrane.
165. The system of claim 164, wherein at least one of the valves is operable with the membrane.
166. The system of claim 164, wherein the flexible membrane is made of material including a polyolefin.
167. The system of claim 162, wherein a ratio of the second fluid to the first fluid is controlled to be from 0.2% to 3%.
168. The system of claim 162, wherein a ratio of fluid exiting the first and second outlet paths is controlled to be from 0.1% to 7%.
169. The system of claim 162, wherein at least one of the first and second inlet paths and the first and second outlet paths are connected upstream and downstream, respectively, of the pump.
170. The system of claim 162, wherein at least one of the first and second inlet paths and the first and second exhaust paths feeds directly into the pump.
171. The system of claim 162, which includes a plurality of pumps, each of the pumps communicating with first and second inlet paths, first and second intake valves, first and second outlet paths and first and second exhaust valves.
172. The system of claim 171, wherein at least one first inlet path, second inlet path, first outlet path and second outlet path connects fluidly to each of the plurality of pumps.
173. The system of claim 171, wherein first and second pumps perform in at least one manner selected from the group consisting of: (i) both intake the first fluid; (ii) intake first and second fluids, respectively; (iii) intake second and first fluids, respectively; and (iv) both intake the second fluid.
174. The system of claim 171, wherein first and second pumps are operated alternatingly.
175. The system of claim 174, wherein the first pump pumps in the first fluid through the first inlet path and the first intake valve that communicate with the first pump, while the second pump outputs fluid through the first outlet path and the first exhaust valve that communicate with the second pump.
176. The system of claim 174, wherein the first pump pumps in the first fluid through the first inlet path and the first intake valve that communicate with the first pump, while the second pump outputs fluid through the second outlet path and the second exhaust valve that communicate with the second pump.
177. The system of claim 174, wherein the first pump pumps in the second fluid through the second inlet path and the second intake valve that communicate with the first pump, while the second pump outputs fluid through the first outlet path and the first exhaust valve that communicate with the second pump.
178. The system of claim 174, wherein the first pump pumps in the second fluid through the second inlet path and the second intake valve that communicate with the first pump, while the second pump outputs fluid through the second outlet path and the second exhaust valve that communicate with the second pump.
179. The system of claim 162, wherein the treatment is selected from the group consisting of: continuous flow peritoneal dialysis, automated peritoneal dialysis, tidal flow peritoneal dialysis, hemodialysis and hemofiltration.
180. The system of claim 162, wherein at least one of the first and second inlet paths communicate fluidly with a source selected from the group consisting of: a regeneration device, at least one dialysate supply, at least one additive source and a patient.
181. The system of claim 162, wherein at least one of the first and second outlet paths communicates fluidly with a destination selected from the group consisting of: a patient, a sample container and an ultrafiltrate bag.
182. The system of claim 162, wherein at least one of the first and second paths includes a plurality of fluid lumens that allows flow to travel in two directions.
183. A system for performing dialysis comprising: first and second inlet paths in communication with a pump; first and second intake valves communicating respectively with the first and second inlet paths; first and second outlet paths in communication with the fluid pump; first and second exhaust valves communicating respectively with the first and second outlet paths; and a controller that selectively opens the valves.
184. The system of claim 183, wherein the controller controls a proportion of a fluid flowing through the first and second outlet paths.
185. The system of claim 183, wherein the controller controls a proportion of first and second fluids pumped from the first and second inlet paths.
186. The system of claim 183, which includes a plurality of portions of a disposable cassette forming part of a plurality of corresponding fluid pumps, the fluid pumps communicating with the first and second inlet paths, the first and second intake valves, the first and second outlet paths and first and second exhaust valves.
187. The system of claim 186, wherein the cassette defines a fluid flow portion of at least one of the first and second intake valves and the first and second exhaust valves.
188. The system of claim 186, wherein the cassette defines at least a portion of a port vent.
189. The system of claim 186, which includes at least one flexible membrane connected to the cassette, the membrane made of a material including a polyolefin.
190. The system of claim 186, wherein the controller causes the fluid pumps to move to align the cassette before pumping begins.
191. The system of claim 183, wherein the controller employs at least one pumping rule to operate the pump.
192. The system of claim 183, which includes a plurality of fluid sources and a plurality of fluid destinations, wherein the controller operates the pump according to a pumping schedule to pump from at least one source to at least one destination.
193. The system of claim 183, wherein at least one of the inlet paths is in communication with a dialysate supply.
194. The system of claim 183, wherein at least one of the inlet paths is in communication with a fluid regeneration device.
195. A method for performing dialysis comprising the steps of: (a) pumping dialysis fluid to a pump through a first inlet valve; (b) pumping a dialysis additive fluid to the pump through a second inlet valve; (c) pumping the dialysis fluid from the pump through a first outlet valve to a patient; and (d) pumping the dialysis fluid from the pump through a second outlet valve to another destination.
196. The method of claim 195, wherein steps (a) to (d) are each performed at different times.
197. The method of claim 195, wherein steps (a) and (d) are performed together.
198. The method of Class
199. The method of claim 195, wherein the pump is a first pump and step (a) is performed while pumping dialysis fluid from a second pump to the patient.
200. The method of claim 195, wherein the pump is a first pump and step (a) is performed while pumping dialysis fluid from a second pump to the other destination.
201. The method of claim 195, wherein the pump is a first pump and step (b) is performed while pumping the dialysis additive fluid to a second pump.
202. The method of claim 195, wherein the pump is a first pump and step (d) is performed while pumping from a second pump to the other destination.
203. The method of claim 195, wherein a volume of fluid pumped in at least one of steps (b) and (d) is controlled by a partial pump stroke.
204. The method of claim 195, wherein the other destination is selected from the group consisting of: an ultrafiltration removal container, a sample container, a drain and an accumulator.
205. The method of claim 195, which includes the step of pumping fluid from the patient through the first outlet valve.
206. The method of claim 195, which includes the step of pumping dialysis fluid for a number of pump strokes before pumping the additive.
207. The method of claim 195, which includes the step of pumping fluid to the patient for a number of pump strokes before pumping to the other destination.
208. A method for operating medical fluid pumps comprising the steps of: connecting fluidly a plurality of fluid sources to a pump via a plurality of intake valves; connecting fluidly a plurality of fluid destinations to the pump via a plurality of exhaust valves; and controlling the fluid flow from the sources to the destinations through the pump using a pumping schedule.
209. The method of claim 208, which includes the step of developing the pumping schedule after receiving at least one input parameter.
210. The method of claim 208, which includes connecting fluidly the sources and the destinations to a plurality of pumps and controlling flow through the pumps via the schedule.
211. The method of claim 208, which includes controlling the valves by compressing valve springs associated with the valves.
212. A method for operating a medical fluid pumping system comprising the steps of: inputting at least one patient parameter; calculating at least one value based on the inputted parameter; using the calculated value and at least one flow restricting rule to develop a pumping schedule; and operating at least one medical fluid pump according to the schedule.
213. The method of claim 212, wherein inputting the parameter includes inputting a value selected from a range of values for the parameter.
214. The method of claim 212, which includes prompting a plurality of parameters to be entered.
215. The method of claim 212, wherein inputting the parameter includes ensuring that the inputted parameter is safe operationally.
216. The method of claim 212, wherein the parameter is selected from the group consisting of: (i) a total therapy time; (ii) a cycle therapy time; (iii) a dialysate flowrate; (iv) an add concentration flowrate; (v) an ultrafiltrate removal flowrate; (vi) a patient ultrafiltrate generation flowrate; and (vii) a ratio between the dialysate flowrate and an accumulation flowrate.
217. The method of claim 212, wherein calculating the value includes calculating a number of pump strokes.
218. The method of claim 212, wherein calculating the value includes calculating a first number of a first type of pump stroke and a second number of a second type of pump stroke.
219. The method of claim 212, wherein the value is selected from the group consisting of: a stroke time, a number of patient strokes, a number of accumulation strokes, a number of concentration add strokes and a number of ultrafiltrate removal strokes.
220. The method of claim 212, which includes implementing at least one rule based on a physical limitation of the medical fluid pumping system.
221. The method of claim 212, which includes implementing at least one rule based on a therapy limitation of the medical fluid pumping system.
222. The method of claim 212, which includes, according to the schedule, operating at least one pump to pump from a desired fluid source.
223. The method of claim 212, which includes, according to the schedule, operating at least one pump to pump to a desired fluid destination.
224. The method of claim 212, wherein operating the medical fluid pump includes recirculating medical fluid from a patient, through a regeneration device, back to the patient.
225. The method of claim 212, wherein operating the medical fluid pump includes performing a number of tidal flow partial fluid exchanges.
226. The method of claim 212, wherein operating the medical fluid pump includes performing hemodialysis or hemofiltration using the pump.
227. The method of claim 212, wherein operating the medical fluid pump includes controlling a device selected from the group consisting of: a spring, a spring coupled sealing to a moving diaphragm, a spring-loaded piston cylinder, a linear actuator and a rotary motor coupled to a rotational/linear motion converter.
228. A system for performing a dialysis therapy comprising: at least one fluid pump; at least one fluid solution; at least one fluid destination; and a controller that controls fluid pumping from the solution to the destination using at least one user inputted parameter and at least one software restraint based on a fluid connection between the source, pump and destination.
229. The system of claim 228, wherein the controller further controls the fluid pumping using at least one software restraint based on the therapy.
230. The system of claim 228, wherein the controller further controls the fluid pumping using a pumping state limitation.
231. The system of claim 228, which includes a pump actuator and a disposable cassette operating collectively to form the fluid pump.
232. The system of claim 231, wherein the pump actuator is attached to a housing along with at least one pneumatic valve.
233. The system of claim 228, wherein the fluid solution is selected from the group consisting of: a fluid supply, a regeneration device, a patient, an accumulator, an additive source and any combination thereof.
234. The system of claim 228, wherein the fluid destination is selected from the group consisting of: a patient, a regeneration device, an accumulator, a sample container, an ultrafiltrate container and any combination thereof.
235. The system of claim 228, wherein the fluid connection restraint is based on how many solutions are connected fluidly to the pump.
236. The system of claim 228, wherein the fluid connection restraint is based on how many pumps are connected fluidly to the solution.
237. The system of claim 228, wherein the fluid connection restraint is based on how many destinations are connected fluidly to the pump.
238. The system of claim 228, wherein the fluid connection restraint is based on how many pumps are connected fluidly to the destination.
239. The system of claim 228, which includes a heater and a gas separation chamber placed downstream from the heater.
240. A system for performing a dialysis therapy comprising: at least one fluid pump; at least one fluid solution; at least one fluid destination; and a controller that controls fluid pumping from the solution to the destination using at least one user inputted parameter and at least one therapy-based software restraint.
241. The system of claim 240, wherein the controller further controls the fluid pumping using a pumping state limitation.
242. The system of claim 240, wherein the therapy restraint is selected from the group consisting of: (i) a prohibition from pumping from the same pump simultaneously to more than one destination; (ii) a prohibition from pumping into the same pump simultaneously from more than one solution; (iii) a prohibition from pumping the same solution simultaneously into more than one pump; (iv) a prohibition from pumping into the same destination from more than one pump; (v) a prohibition from pumping from a fluid supply directly to drain; (vi) a prohibition form pumping from an additive source to an ultrafiltrate receptacle; (vii) a prohibition from pumping from one place to the same place and (viii) any combination thereof.
243. The system of claim 240, wherein the pump moves a flexible membrane made of a material including a polyolefin.
244. A flow pumping schedule for a medical fluid system having at least one pump, at least one fluid solution and at least one fluid destination, the schedule prepared by a process comprising the steps of: inputting at least one patient parameter; calculating at least one value based on the inputted parameter; and using the calculated value and at least one flow restricting rule in a computer program, the program generating the schedule.
245. The schedule of claim 244, which includes a number of entries, the entries separated according to a pumping stroke duration.
246. The schedule of claim 244, which includes a plurality of entries, each entry assigning at least one pump to pump from a fluid source or to a fluid destination.
247. A disposable dialysis cassette comprising: a rigid portion; at least one membrane attached to the rigid portion; a vent port aperture formed integrally with the rigid portion; and a filter placed across to the aperture.
248. The disposable cassette of claim 247, which includes a vent port extending integrally from the rigid portion, the port defining the aperture.
249. The disposable cassette of claim 247, which includes a bushing, the filter fixed to the bushing, the bushing fixed to the rigid portion.
250. The disposable cassette of claim 247, wherein the filter is a hydrophobic membrane.
251. The disposable cassette of claim 247, wherein the filter is made from a material selected from the group consisting of: polytetrafluorethylene (“PTFE”), Teflon, nylon, polyethylene, polypropylene, polystyrene, polyvinylchloride (“PVC”), polyvinylidene, a polyamide, and any combination thereof.
252. The disposable cassette of claim 247, wherein a pair of flexible pumping membranes are disposed on opposing sides of the rigid portion.
253. The disposable cassette of claim 252, wherein the filter is disposed on a vent port that extends from an edge of the rigid portion not covered by the membranes.
254. The disposable cassette of claim 252, wherein the membrane is made of material including a polyolefin.
255. The disposable cassette of claim 247, wherein the vent port is in fluid communication with a patient fluid line connected to the rigid portion.
256. The disposable cassette of claim 247, which includes a flared vent port extending integrally from the rigid portion, the port defining the aperture.
257. The disposable cassette of claim 247, wherein the filter is attached by a method selected from the group consisting of: adhering, heat sealing, mechanically attaching and any combination thereof.
258. A system for performing a dialysis therapy comprising: at least one fluid pump; a patient line in communication with the fluid pump; a disposable member placed in contact with the pump, the disposable member defining a port; and a venting filter positioned at the end of the port.
259. The system of claim 258, wherein the port is in communication with at least one of the pump and the patient line.
260. The system of claim 258, which includes a controller connected operably to the pump, the controller and pump performing a priming sequence, the venting filter allowing air to escape during the priming sequence.
261. The system of claim 258, wherein the controller commands the pump to move towards the member to align the member properly before beginning the priming sequence.
262. The system of claim 258, wherein the venting filter allows air to escape when the pump pumps fluid from a fluid source to the patient line.
263. The system of claim 262, wherein the source is a first fluid source and which includes a second fluid source in communication with the pump.
264. The system of claim 258, wherein the patient line is a line carrying fluid from the pump to the patient and which includes a second patient line carrying fluid from the patient.
265. The system of claim 264, which includes a fluid regeneration device in connection with the second patient line.
266. The system of claim 258, wherein the therapy is selected from the group consisting of: continuous flow peritoneal dialysis, automated peritoneal dialysis, tidal flow peritoneal dialysis, hemodialysis and hemofilration.
267. The system of claim 258, wherein the pump is a first pump and which includes a second pump in communication with the port.
268. A method of manufacturing a disposable dialysis cassette comprising the steps of: molding a rigid portion to define a plurality of fluid channels and venting aperture; attaching at least one flexible membrane to the rigid portion; and placing a venting filter over the aperture.
269. The method of claim 268, which includes heat sealing the membrane to the rigid portion.
270. The method of claim 268, which includes connecting the venting filter to a port that defines the aperture and is formed integrally with the rigid portion.
271. The method of claim 270, which includes molding the port to have a conical shape.
272. The method of claim 268, which includes the step of connecting the filter to a bushing and connecting the bushing to a port that defines the aperture.
273. The method of claim 268, which includes using the membrane to at least partially secure the filter to the rigid portion.
274. A gas separation chamber for use in dialysis therapy comprising: a housing having a fluid inlet, a fluid outlet disposed adjacent to a fluid collection portion of the housing, and a vent opening disposed adjacent to a gas collection portion of the housing; and a capacitive sensor that produces an output indicative of the amount of gas in the housing.
275. The gas separation chamber of claim 274, which includes a member positioned within the housing so as to deflect fluid entering the fluid inlet.
276. The gas separation chamber of claim 274, which includes a member position within the housing so as to at least partially block fluid from escaping through the valve opening.
277. The gas separation chamber of claim 274, which includes a valve in communication with the vent opening.
278. The gas separation chamber of claim 274, which includes a plurality of valves in communication with the vent opening.
279. The gas separation chamber of claim 274, which includes a vent membrane in fluid communication with vent opening.
280. The gas separation chamber of claim 279, wherein the membrane is of a material selected from the group consisting of: a hydrophobic membrane and the dialysis disposable of polytetrafluorethylene (“PTFE”), Teflon, nylon, polyethylene, polypropylene, polystyrene, polyvinylchloride (“PVC”), polyvinylidene, a polyimide, and any combination thereof.
281. The gas separation chamber of claim 274, wherein the capacitive sensor includes a plurality of metal plates.
282. The gas separation chamber of claim 274, wherein the fluid collection portion is located at the bottom of the chamber.
283. The gas separation chamber of claim 274, wherein the gas collection portion is located at the top of the housing.
284. The gas separation chamber of claim 274, wherein the therapy is selected from the group consisting of: continuous flow peritoneal dialysis, automated peritoneal dialysis, tidal flow peritoneal dialysis, hemodialysis and hemofiltration.
285. A system for performing dialysis comprising: a patient line; a pump that pumps fluid to the patient line; a heater that heats the fluid placed between the pump and the patient fluid line; a first air separation device associated with the pump; and a second air separation device positioned downstream of the heater.
286. The system of claim 285, wherein the second air separation device is positioned upstream of the patient fluid line.
287. The system of claim 285, wherein the first air separation device is located in a disposable cassette connected fluidly to the patient line.
288. The system of claim 287, wherein the disposable cassette houses at least one of a portion of the pump and a fluid heating pathway for the heater.
289. The system of claim 285, wherein the disposable cassette includes a rigid portion defining a port vent.
290. The system of claim 285, wherein the second air separation device includes at least one capacitive sensor.
291. The system of claim 285, wherein the second air separation device includes a plurality of sequentially operated fluid valves.
292. The system of claim 285, wherein the second air separation device is coupled operably to at least one exhaust valve.
293. The system of claim 292, wherein the exhaust valve is positioned between the second air separation device and a vent membrane.
294. The system of claim 285, which includes a fluid trap positioned between the second air separation device and a vent membrane.
295. The system of claim 285, wherein the pump connects operably to a plurality of inlet paths and plurality of outlet paths.
296. The system of claim 285, wherein the pump is driven by a spring and a vacuum.
297. The system of claim 285, wherein the pump moves a flexible membrane made from a material including a polyolefin.
298. A method of operating a dialysis system comprising the steps of: pumping dialysis fluid; removing gas from the pumped fluid; heating the fluid; and removing gas released from the heated fluid.
299. The method of claim 298, which includes pumping the fluid from a fluid supply.
300. The method of claim 298, which includes pumping the fluid in a recirculating loop.
301. The method of claim 298, wherein removing released gas includes the step of opening a vent upon sensing an amount of gas in a chamber.
302. The method of claim 301, wherein sensing the gas amount includes capacitive sensings.
303. The method of claim 301, which includes the further step of closing the vent upon sensing a second, lesser amount of gas in the chamber.
304. The method of claim 298, wherein removing released gas includes opening sequentially a plurality of valves placed in series.
305. A method of operating a dialysis system comprising the steps of: pumping dialysis fluid; and using capacitive sensing to determine a volume of the fluid pumped; and using capacitive sensing to determine a volume of a gas released from the fluid pumped.
306. The method of claim 305, which includes using capacitive sensing to sense gas released from the fluid via heating.
307. The method of claim 305, which includes capacitive sensing to sense gas released from the fluid during priming.
308. The method of claim 305, which includes the step of venting the volume of fluid released when a setpoint volume of gas is reached.
309. The method of claim 305, which includes the step of venting the volume of fluid released at certain points in time.
310. A method of operating a dialysis system comprising the steps of: pumping dialysis fluid; and venting a volume of gas released from the fluid while pumping the fluids.
311. The method of claim 310, which includes venting the volume by operating sequentially a plurality of values.
312. The method of claim 311, which includes collecting residual dialysis fluid from the volume released between values.
313. A dialysis system comprising: a pumping cassette having a rigid portion that defines integrally a venting aperture; and a spring operated pump piston that contacts the cassette.
314. A dialysis system comprising: a housing, a pump actuator and a plurality of pneumatic valves fixed to the housing; and a plurality of inlet paths communicating with a plurality of medical fluids via respective ones of the valves with a pump chamber operated by the pump actuator.
315. A dialysis system comprising: a cassette including at least one flexible membrane made from a material including a polyolefin; and a controller that uses at least one flow restricting rule to schedule flow of at least one fluid, through at least one pump chamber defined by the cassette, to at least one destination.
[0001] This application claims the benefit under 35 U.S.C. § 119(e) of U.S. Provisional Patent Application Serial No. 60/397,045, filed on Jul. 19, 2002 and U.S. Provisional Patent Application Serial No. 60/397,268, filed on Jul. 19, 2002.
BACKGROUND OF THE INVENTION
[0002] The present invention generally relates to medical fluid systems. More specifically, the present invention relates to systems and methods of performing cassette-based dialysis and devices related thereto.
[0003] Due to various causes, a person's renal system can fail. Renal failure produces several physiological derangements. The balance of water, minerals and the excretion of daily metabolic load is no longer possible and toxic end products of nitrogen metabolism (urea, creatinine, uric acid, and others) can accumulate in blood and tissues.
[0004] Kidney failure and reduced kidney function have been treated with dialysis. Dialysis removes waste, toxins and excess water from the body that would otherwise have been removed by normal functioning kidneys. Dialysis treatment for replacement of kidney functions is critical to many people because the treatment is life saving.
[0005] Hemodialysis and peritoneal dialysis are two types of dialysis therapies used commonly to treat loss of kidney function. Hemodialysis treatment utilizes the patient's blood to remove waste, toxins and excess water from the patient. The patient is connected to a hemodialysis machine and the patient's blood is pumped through the machine. Catheters are inserted into the patient's veins and arteries so that blood can flow to and from the hemodialysis machine. The blood passes through a dialyzer of the machine, which removes waste, toxins and excess water from the blood. The cleaned blood is returned to the patient. A large amount of dialysate, for example about 120 liters, is consumed to dialyze the blood during a single hemodialysis therapy. Hemodialysis treatment lasts several hours and is generally performed in a treatment center about three or four times per week.
[0006] Peritoneal dialysis uses a dialysis solution or “dialysate”, which is infused into a patient's peritoneal cavity via a catheter. The dialysate contacts the peritoneal membrane of the peritoneal cavity. Waste, toxins and excess water pass from the patient's bloodstream, through the peritoneal membrane and into the dialysate due to diffusion and osmosis, i.e., an osmotic gradient occurs across the membrane. The spent dialysate is drained from the patient, removing waste, toxins and excess water from the patient. This cycle is repeated.
[0007] There are various types of peritoneal dialysis therapies, including continuous ambulatory peritoneal dialysis (“CAPD”), automated peritoneal dialysis (“APD”), including tidal flow APD and continuous flow peritoneal dialysis (“CFPD”). CAPD is a manual dialysis treatment. The patient connects manually an implanted catheter to a drain, allowing spent dialysate fluid to drain from the peritoneal cavity. The patient then connects the catheter to a bag of fresh dialysate, infusing fresh dialysate through the catheter and into the patient. The patient disconnects the catheter from the fresh dialysate bag and allows the dialysate to dwell within the peritoneal cavity, wherein the transfer of waste, toxins and excess water takes place. After a dwell period, the patient repeats the manual dialysis procedure, for example, four times per day, each treatment lasting about an hour. Manual peritoneal dialysis requires a significant amount of time and effort from the patient, leaving ample room for improvement.
[0008] Automated peritoneal dialysis (“APD”) is similar to CAPD in that the dialysis treatment includes drain, fill, and dwell cycles. APD machines, however, perform the cycles automatically, typically while the patient sleeps. APD machines free patients from having to manually perform the treatment cycles and from having to transport supplies during the day. APD machines connect fluidly to an implanted catheter, to a source or bag of fresh dialysate and to a fluid drain. APD machines pump fresh dialysate from the dialysate source, through the catheter, into the patient's peritoneal cavity and allow the dialysate to dwell within the cavity and the transfer of waste, toxins and excess water to take place. APD machines pump spent dialysate from the peritoneal cavity, though the catheter, to the drain. As with the manual process, several drain, fill and dwell cycles occur during APD. A “last fill” occurs at the end of CAPD and APD, which remains in the peritoneal cavity of the patient until the next treatment.
[0009] Both CAPD and APD are batch type systems that send spent dialysis fluid to a drain. Tidal flow systems are modified batch systems. With tidal flow, instead of removing all the fluid from the patient over a longer period of time, a portion of the fluid is removed and replaced after smaller increments of time.
[0010] Continuous flow or CFPD systems clean or regenerate spent dialysate instead of discarding it. The systems flow fluid into or out of the patient, through a loop. Dialysate flows into the peritoneal cavity through one catheter lumen and out another catheter lumen. The fluid exiting the patient passes through a reconstitution device that removes waste from the dialysate, e.g., via a urea removal column that employs urease to enzymatically convert urea into ammonia. The ammonia is then removed from the dialysate by adsorption prior to reintroduction of the dialysate into the peritoneal cavity. Additional sensors are employed to monitor the removal of ammonia. CFPD systems are more complicated typically than batch systems.
[0011] Hemodialysis, APD (including tidal flow) and CFPD systems can employ a pumping cassette. The pumping cassette typically includes a flexible membrane that is moved mechanically to push and pull dialysis fluid out of and into, respectively, the cassette. Certain known systems include flexible sheeting on one side of the cassette, while others include sheeting on both sides of the cassette. Positive and/or negative pressure can be used to operate the pumping cassettes.
[0012] One problem with the pumping cassettes is leakage. If the flexible membranes experience a pinhole or tear, fluid and air can move from one side of the membrane to the other. Movement of fluid from inside the cassette to the inner workings of the machine can damage the machine. Movement of air from the machine into the cassette can compromise the sterility of the fluid pathways defined by the cassette. There are detection systems that determine when fluid leaks from the cassette to the machine. It is more difficult, however, to detect fluid leaking into the cassette.
[0013] Another problem with cassette-based pumping occurs when the cassette is loaded improperly into the machine. Proper alignment is important because portions of the flexible membrane must match corresponding machine portions, e.g., pump and valve actuators. Improper loading can lead to undue mechanical stress being placed on the cassette, harming potentially the cassette and/or the actuator. Improper cassette loading will also likely degrade or prohibit performance of the system.
[0014] A further dilemma, especially in CFPD, is the coordination of multiple fluid delivery. Cassette-based peritoneal pumping systems that administer fluids continuously to patients are required to withdraw fluid (ultrafiltrate) from and add fluid (concentrate) to a continuously flowing dialysis fluid loop. The additional fluids have typically necessitated additional dedicated pumps, which make the cassette and dialysis machine larger and noisier. Scheduling the operation of multiple pumps also presents a challenge to system implementers.
[0015] Another problem associated with cassette-based pumping is the entrapment of air or other gas into the fluid pathways. Air can enter the system via leaking connections, improper priming, faulty tubing and faulty cassettes. Patient therapy also produces various gases that enter the system. Cassette-based pumps are designed to pump fluid, not gas. Moreover, the removal and delivery of fluid from and to the patient needs to be monitored and controlled. Air and gases upset volume measurement systems that assume no air or gas exists in the fluid pathways. Air and gases can also be uncomfortable for the patient and impede proper waste removal.
[0016] It is desirable to remove air and gas from the dialysis fluid before the fluid enters the patient. To this end, cassettes-based systems have been provided with air or gas vents. A need continues however to provide for more economical venting systems. Further, prior to infusion, the dialysis fluid solution is heated to body temperature, releasing gas from the solution. Known vents do not vent air or gas due to fluid heating. It is also desirable to have a method for detecting air and fluid, so that the volume of both can measured, detecting air for purging and detecting fluid for ensuring proper therapy.
SUMMARY OF THE INVENTION
[0017] In general, the present invention relates to medical fluid delivery systems that employ a pumping cassette. In particular, the present invention provides systems, methods and apparatuses for cassette-based dialysis therapies including hemodialysis, CAPD, APD (including tidal modalities) and CFPD, as these therapies have been described above.
[0018] In one embodiment, the systems, methods and apparatuses of the present invention are used with CFPD. The CFPD therapy includes, generally, a fluid circuit or loop connected to a patient, allowing dialysate or other suitable therapy fluid to be circulated into, through and out of the patient's peritoneal cavity to remove a therapeutic effective amount of excess water and solutes, such as uremic toxins, urea, creatinine and the like.
[0019] In an embodiment, the dialysate is continuously circulated along the fluid loop multiple times prior to discharge. The volume of dialysate consumed is minimized with respect to batch systems. The circulation can take the form of a single pass or multiple passes. One single pass system operable with the cassette-based systems, methods and apparatuses of the present invention is described in document Serial No. 60/397,045. One multiple pass system operable with the cassette-based systems, methods and apparatuses of the present invention is described in document Serial No. 60/397,268.
[0020] As discussed above, the present invention is not limited to CFPD. One APD system operable with the cassette-based systems, methods and apparatuses of the present invention is described in U.S. patent application Ser. No. 10/155,603, entitled, “Automated Dialysis System” the teachings of which are incorporated herein by reference. With these types of dialysis systems in mind, some of the various embodiments of the present invention are hereafter summarized.
[0021] In one embodiment, the present invention provides an actuator assembly that operates with the disposable cassette. The assembly includes a housing that holds both the pump actuators and the valve actuators. The pump/valve manifold eliminates the need for separate valve manifolds. This in turn reduces significantly the amount of tubing and tubing connections that would otherwise have to be made between one or more valve manifolds and a pump actuator housing. The combination pump/valve manifold also conserves space and materials, allowing for a smaller, lighter and more cost effective dialysis machine.
[0022] In another embodiment of the present invention, a fail safe valve and pump arrangement is provided. The arrangement allows fluid to flow only from the cassette into the machine in the event of a cassette failure. A positive pressure gradient is maintained from the cassette to the machine, generally preventing air from entering the cassette. The arrangement also ensures that all valves close in the event of a system failure or power failure, preventing fluid from mixing across fluid pathways in the cassette.
[0023] The arrangement includes a disposable cassette operable with one or more diaphragm pump chambers, one or more diaphragm valve seats and one or more fluid pathways. The cassette is constructed of a rigid or semi-rigid body portion (referred to collectively herein as “rigid portion”) having flexible sheeting sealed to one or both sides of the portion. The cassette with sheeting is mated with at least one pump and at least one valve driver mechanism, creating an interconnected fluidics system.
[0024] During operation, a vacuum is normally maintained between the cassette sheeting and the pump/valve driver interface wherever a pump, valve, or fluid pathway is created. This creates a positive pressure gradient from the cassette to the components of the dialysis machine. The valve plungers press the sheeting against the rigid portion of the cassette, closing the valves unless a vacuum (or pressure) is provided to mechanisms that retract the valve plungers.
[0025] The pump actuators may be configured to extend, retract or hold position in the event of system failure and include a piston having a piston head. The piston head pushes against a flexible membrane of the disposable cassette to dispel fluid from the cassette. Various actuators are provided to move the piston heads. One actuator, for example, includes a first or deep vacuum that draws the piston head away from the cassette and a second shallow vacuum that pulls the membrane away from the cassette, causing dialysis fluid to enter the cassette. In an embodiment, a spring cavity is located on the end of the piston opposite the piston head. The spring cavity houses a spring, which when the deep vacuum is not present, pushes the piston, piston head and cassette sheet into the rigid portion of the cassette. When the deep vacuum is applied, the deep vacuum overcomes the compression resistance of the spring and compresses the spring.
[0026] To separate the deep and shallow vacuums, a rolling diaphragm is sealed to the pump piston and the walls of the spring housing. The rolling diaphragm includes enough take-up material to allow the piston to move back and forth. To ensure that the take-up material of the diaphragm rolls or moves properly, a shallow vacuum is left in the spring housing (i.e., in place of the deep vacuum) when the deep vacuum is removed. The shallow vacuum is not strong enough to overcome the compression resistance of the spring but is strong enough to keep the rolling diaphragm from inverting due to the shallow vacuum maintained around the piston head that seals the membrane to the piston head. Alternatively, multiple rolling diaphragms are used, with atmospheric air applied between the diaphragms.
[0027] One alternative valve actuator replaces the diaphragm with a piston-cylinder, which is activated via negative or positive pressure. Another alternative valve actuator replaces the diaphragm, spring and deep vacuum altogether with an electrically operated actuator, such as a stepper motor (linear or rotary), servo motor or other type of linear actuator. A shallow vacuum is still applied to seal the cassette membrane to the piston head.
[0028] A fail safe valve is also provided, which makes use of the deep and shallow vacuum in an embodiment. The valve utilizes a spring and negative pressure to operate a valve plunger that contacts the flexible membrane of the disposable cassette. The valve also seals to a moveable diaphragm that separates different vacuums. A deep vacuum is applied to compress the spring, moving the valve plunger away from the cassette. A shallow vacuum is applied to the opposite side of the diaphragm from the spring housing and causes the flexible membrane of the cassette to move with the valve plunger. The shallow vacuum also aids the spring to push the plunger against the flexible membrane, increasing the valve sealing force. The deep vacuum is strong enough therefore to overcome the spring's compression resistance and the shallow vacuum.
[0029] In a further embodiment of the present invention, a method and apparatus for automatically aligning the disposable cassette within the machine is provided. The procedure attempts to correct smaller misalignments, sends an error for larger misalignments, helps to ensure cassette quality and provides cassette integrity testing.
[0030] The method includes loading the cassette into the dialysis machine and, before inflating a sealing bladder, moving one or more pump pistons toward respective pump cavities. This action causes the cassette to shift, if need be, into its proper position. If a resistance to the movement of the piston(s) is detected, the dialysis machine knows that a problem has occurred either with the cassette or the mechanics of the machine and can take action appropriately. The procedure is operable whether the cassette loads horizontally on top of the machine, or vertically on a side of the machine. After the alignment procedure takes place, a bladder inflates and compresses the cassette against an inner surface of the dialysis machine, the pump pistons and valve plungers. The cassette is then ready for use. A sensor is also provided, such as a strain gauge, which monitors the force exerted by the moving pistons on the cassette. If the disposable cassette is out of alignment to the point that alignment cannot be corrected, the sensor detects the undue stress placed on the piston head, sends an error message and de-energizes the pumps.
[0031] In yet another embodiment of the present invention, a material for the flexible membrane is provided. The material is fabricated from a non-PVC containing, thermoplastic polymeric material and can be of a monolayer structure or a multiple layer structure. The film can be fabricated using standard thermoplastic processing techniques such as extrusion, coextrusion, extrusion lamination, lamination, blown extrusion, tubular extrusion, cast extrusion or coextrusion, compression molding and thermoforming.
[0032] In still a further embodiment of the present invention, a valve arrangement is provided that allows different fluids to be combined and removed from a medical fluid system. The valve arrangement is operable with a single pump or multiple fluid pumps. The arrangement is described in connection with CFPD but is operable with other types of dialysis. In the illustrated embodiment, the arrangement allows concentrate to be added and ultrafiltrate to be withdrawn from a dialysis fluid in a continuous or semi-continuous manner, without requiring additional fluid pumps.
[0033] The valve arrangement adds an additional inlet valve and outlet valve for each pump. To this end, each pump operates with a main intake valve that provides on/off control for the inlet flow of dialysate in a continuous loop (CFPD) or from a supply bag (APD). A second intake valve operates in parallel with the main intake valve and provides on/off control for a concentrate or additive (CFPD) or parallel dialysate supply (APD). Each pump operates with a main exhaust valve that provides on/off control for the outlet flow of dialysate, e.g., to the patient. A second exhaust valve operates in parallel with the main outlet valve and provides on/off control for, e.g., the removal of ultrafiltrate from the dialysis fluid.
[0034] When the second intake and exhaust valves are open, the main valves are closed and vice versa in an embodiment. The relevant amount of time that the main versus the second valves are open determines how quickly concentrate is added or ultrafiltrate is removed. For instance one pump volume's worth of concentrate can be pumped once every thirty-three pump strokes or once every five hundred pump strokes.
[0035] In one implementation, a pair of multiplexed pumps is provided, yielding alternating and virtually continuous flow of fluid to the patient. In this implementation, a number of variations arise. For example, the secondary intake valves or the secondary exhaust valves can be open simultaneously, doubling concentrate intake or ultrafiltrate removal. Still further, partial fills can be employed via the second valves by only partially moving the pump piston.
[0036] In still a further embodiment of the present invention, an expert system and method for scheduling the pumping of one or more solutions, via one or more pumps and to one or more destinations is provided. The system and method are illustrated with respect to CFPD but are also applicable to APD and hemodialysis. The expert system uses a set of rules. The rules are derived from physical limitations, e.g., fluid flow connections and pumping state limitations. The rules are also derived from therapy limitations, e.g., it is undesirable to pump concentrate directly to ultrafiltrate collection, and arbitrary limitations, e.g., no partial pump strokes.
[0037] The expert system also accounts for a number of parameters inputted by the patient or doctor. The system applies various algorithms to the inputted values to yield the output requirements for the therapy, e.g., overall flow volume, flowrate, therapy time, total concentrate added, etc. Using the outputs and the rules or restrictions, the expert system develops a pumping schedule having a number of entries. Each entry directs one or more pump to pull or push from one or more solution or to one or more destinations, respectively. The controller of the system commands the pumps to execute the pumping profile set forth in the schedule. The schedule may represent a portion of the overall therapy, wherein the schedule is cycled a number of times until therapy is complete. In the end, the outputs are achieved according to the rules and other limitations, such as fluid pressure level limitations.
[0038] In yet another embodiment of the present invention, a port vent for venting air purged from the dialysis fluid is provided. The port vent is integral to the cassette and vents the priming volume as well as air entrained due to pumping and patient exhaust gases. The cassette-based port vent is molded integrally with the rigid portion of the cassette, taking advantage of the fact that the rigid portion is otherwise a molded structure. A filter, such as a 0.2 micron filter is then fixed, e.g., bonded, heat sealed, adhered or mechanically fixed, to the port vent. The filter is made of a material, such as PTFE, Gortex or other polymer, which can be bonded, heat sealed, adhered or fixed mechanically. In an embodiment, the filter is made of a hydrophobic material. Alternatively, the filter is bonded, heat sealed, adhered or fixed to a bushing that fits onto and is suitably attached to the molded port.
[0039] Moreover, in an embodiment an additional air separation chamber for a medical fluid system is provided. The cassette-based port vent provides a first venting mechanism that separates air entrained in the fluid at the point of pumping. After the dialysis fluid leaves the pumping cassette, however, the fluid passes through a heater. The addition of heat releases gas trapped in the solution. This additional released gas must also be purged before the solution enters the patient.
[0040] The additional gas separation chamber is located downstream from the fluid heater. The heat released gas rises to and is trapped at the top of the chamber, while the heated fluid passes through the bottom of the chamber. The chamber houses one or more capacitive sensors that detect the amount of gas in the chamber. When the amount reaches a predetermined level, one or more exhaust valve opens and allows the gas to vent.
[0041] The gases vent through a membrane. To keep the membrane dry, a series of exhaust values may be employed. To this end, a sump fluid trap may alternatively or additionally be provided.
[0042] In still another embodiment, a gas separation device is provided that includes a series of valves that are operated sequentially. A fluid trap is provided in between the valves. The sequential operation of the valves and trap enables gas but not fluid to escape from the system.
[0043] In consideration of the embodiments described herein, it is therefore an advantage of the present invention to provide a cassette actuator assembly that houses both the pump and valve actuators.
[0044] Another advantage of the present invention is to provide a cassette-based medical fluid system having fail safe valve and pump actuation.
[0045] A further advantage of the present invention is to provide a cassette-based medical fluid system having a positive pressure gradient between the cassette fluid pathways and the outlying components of the dialysis machine.
[0046] Still another advantage of the present invention is to provide a cassette-based medical fluid system having a cassette auto-alignment feature.
[0047] Yet another advantage of the present invention is to provide a cassette-based medical fluid system having a cassette misalignment output and a cassette integrity feature.
[0048] Moreover, an advantage of the present invention is to provide an improved material for the flexible membrane of the cassette.
[0049] Still further, an advantage of the present invention is to provide a cassette-based medical fluid system having a multiplexing valve arrangement.
[0050] Further still, an advantage of the present invention is to provide a cassette-based medical fluid system having an expert fluid pumping management system that uses a knowledge base to derive a pumping schedule after parameters are inputted by a doctor/patient.
[0051] Still a further advantage of the present invention is to provide a cassette-based integrally formed port vent.
[0052] Yet a further advantage of the present invention is to provide an air separation chamber downstream of a medical fluid heater.
[0053] Moreover, a further advantage of the present invention is to allow the dialysis fluid to purge entrained gas while the fluid is being pumped.
[0054] Additional features and advantages of the present invention are described in, and will be apparent from, the following Detailed Description of the Invention and the figures.
BRIEF DESCRIPTION OF THE FIGURES
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