Air-in-line and pressure detection
First Claim
1. A method of measuring air content in a sample fluid comprising:
- determining a base volume change between zero or a negative pressure and a positive pressure in a chamber;
determining a sample volume change between zero or the negative pressure and the positive pressure in the chamber with a sample fluid; and
determining air content of the sample fluid by comparing the sample volume change and the base volume change; and
wherein the chamber has an inlet valve, an outlet valve, and an assembly connected to a pressure source, and the assembly comprises a cassette piston.
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Accused Products
Abstract
Methods and apparatus for air content and pressure measurement of sample fluid, especially sample fluid in association with an infusion pump. Volume change in a chamber as the chamber transitions between negative and positive pressure relates to the air content in the chamber. In particular, in an infusion pump, the volume change of infusion fluid as it transitions between being under negative pressure and positive pressure within a cassette central chamber, e.g., pumping chamber, relates to the air content in the infusion fluid. The outlet pressure of the cassette central chamber, e.g., blood pressure, can be monitored based on the cassette central chamber pressure.
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Citations
76 Claims
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1. A method of measuring air content in a sample fluid comprising:
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determining a base volume change between zero or a negative pressure and a positive pressure in a chamber; determining a sample volume change between zero or the negative pressure and the positive pressure in the chamber with a sample fluid; and determining air content of the sample fluid by comparing the sample volume change and the base volume change; and wherein the chamber has an inlet valve, an outlet valve, and an assembly connected to a pressure source, and the assembly comprises a cassette piston. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10)
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11. A method of measuring air content in a sample fluid comprising:
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determining a base volume change between zero or a negative pressure and a positive pressure in a chamber; determining a sample volume change between zero or the negative pressure and the positive pressure in the chamber with a sample fluid; and determining air content of the sample fluid by comparing the sample volume change and the base volume change; and wherein the chamber is closed at the positive pressure.
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12. A method of measuring air content in a sample fluid comprising:
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determining a base volume change between zero or a negative pressure and a positive pressure in a chamber; determining a sample volume change between zero or the negative pressure and the positive pressure in the chamber with a sample fluid; and determining air content of the sample fluid by comparing the sample volume change and the base volume change; and wherein the determination of the base volume change is repeated for one or more times and a lower than average value is selected as the base volume change.
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13. A method of measuring air content in a sample fluid comprising:
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determining a base volume change between zero or a negative pressure and a positive pressure in a chamber; determining a sample volume change between zero or the negative pressure and the positive pressure in the chamber with a sample fluid; and determining air content of the sample fluid by comparing the sample volume change and the base volume change; and wherein the air content of the sample fluid is related to the sample volume change minus the base volume change.
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14. A method of measuring air content in a sample fluid comprising:
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determining a base volume change between zero or a negative pressure and a positive pressure in a chamber; determining a sample volume change between zero or the negative pressure and the positive pressure in the chamber with a sample fluid; and determining air content of the sample fluid by comparing the sample volume change and the base volume change; and calculating an accumulated air content of more than one sample fluids over a period of time. - View Dependent Claims (15)
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16. A method of measuring air content in a sample fluid comprising:
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determining a base volume change between zero or a negative pressure and a positive pressure in a chamber; determining a sample volume change between zero or the negative pressure and the positive pressure in the chamber with a sample fluid; and determining air content of the sample fluid by comparing the sample volume change and the base volume change; and wherein the determining of the base volume change comprises determining a median base volume change with more than one sample of an infusion fluid. - View Dependent Claims (17, 18)
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19. An apparatus for air content measurement of a sample fluid comprising:
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a central chamber; an assembly moving in and out of the central chamber; a pressure source connected to the assembly, and wherein the pressure source comprises a motor which generates a negative pressure in the central chamber and pumps fluid into the central chamber via the assembly, and a spring which generates a positive pressure in the central chamber and pumps fluid out of the central chamber via the assembly; a position sensor connected to the assembly, wherein the position sensor determines a position change of the assembly; and a processor connected to the position sensor, wherein the processor receives the position change of the assembly, calculates a base volume change between zero or a negative pressure and a positive pressure in the central, and a sample volume change between zero or a negative pressure and the positive pressure in the central chamber with a sample fluid, wherein the air content of the sample fluid is related to the sample volume change minus the base volume change. - View Dependent Claims (20, 21, 22, 23, 24, 25, 26, 27, 28, 29, 30, 31, 32, 33, 34, 35, 36)
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37. A method of measuring air content in a sample fluid comprising:
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determining a base volume change between zero or a negative pressure and a positive pressure in a chamber; determining a sample volume change between zero or the negative pressure and the positive pressure in the chamber with a sample fluid; and determining air content of the sample fluid by comparing the sample volume change and the base volume change; and wherein the sample fluid is a body fluid of a mammal. - View Dependent Claims (38, 39, 40)
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41. A method of measuring air content in a sample fluid comprising:
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providing a chamber having an inlet valve, an outlet valve, and an assembly connected to a pressure source operable to draw and pump the sample fluid into and out of, respectively, the chamber; determining air content of the sample fluid based on a volume change of the sample fluid as it transitions between being under a negative pressure and a positive pressure within the chamber; and wherein the determining the air content comprises comparing a) a base volume change between zero or a negative pressure and a positive pressure in a chamber, and b) a sample volume change between zero or the negative pressure and the positive pressure in the chamber with a sample fluid. - View Dependent Claims (42, 43, 44)
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45. A method of measuring air content in a sample fluid comprising:
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providing a chamber having an inlet valve, an outlet valve, and an assembly connected to a pressure source operable to draw and pump the sample fluid into and out of, respectively, the chamber; determining air content of the sample fluid based on a volume change of the sample fluid as it transitions between being under a negative pressure and a positive pressure within the chamber; and wherein the determining the air content comprises determining an accumulated air content of more than one sample fluid over a period of time. - View Dependent Claims (46)
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47. A method of measuring air content in a sample fluid comprising:
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providing a chamber having an inlet valve, an outlet valve, and an assembly connected to a pressure source operable to draw and pump the sample fluid into and out of, respectively, the chamber; determining air content of the sample fluid based on a volume change of the sample fluid as it transitions between being under a negative pressure and a positive pressure within the chamber; and adjusting a fluid flow rate through the chamber based on an air/fluid content proportion in a given stroke of the assembly to compensate for the air content detected in the sample fluid.
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48. A method of measuring air content in a sample fluid comprising:
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providing a chamber having an inlet valve, an outlet valve, and an assembly connected to a pressure source operable to draw and pump the sample fluid into and out of, respectively, the chamber; determining air content of the sample fluid based on a volume change of the sample fluid as it transitions between being under a negative pressure and a positive pressure within the chamber; and determining an effective amount of fluid that is pumped out of the chamber based on the determined air content.
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49. A method of measuring air content in a sample fluid comprising:
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providing a chamber having an inlet valve, an outlet valve, and an assembly connected to a pressure source operable to draw and pump the sample fluid into and out of, respectively, the chamber; determining air content of the sample fluid based on a volume change of the sample fluid as it transitions between being under a negative pressure and a positive pressure within the chamber; and wherein the determining comprises determining a position of the assembly. - View Dependent Claims (50, 51, 52)
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53. A method of measuring air content in a sample fluid comprising:
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providing a chamber having an inlet valve, an outlet valve, and an assembly connected to a pressure source operable to draw and pump the sample fluid into and out of, respectively, chamber; determining air content of the sample fluid based on a volume change of the sample fluid as it transitions between being under a negative pressure and a positive pressure within the chamber; and wherein the sample fluid is a sample of the infusion fluid.
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54. A method of measuring air content in a sample fluid comprising:
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providing a chamber having an inlet valve, an outlet valve, and an assembly connected to a pressure source operable to draw and pump the sample fluid into and out of, respectively, the chamber; determining air content of the sample fluid based on a volume change of the sample fluid as it transitions between being under a negative pressure and a positive pressure within the chamber; and wherein the sample fluid is a body fluid of a mammal. - View Dependent Claims (55, 56, 57)
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58. An apparatus for air content measurement of a sample fluid comprising:
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a central chamber; an assembly moving in and out of the central chamber; a pressure source connected to the assembly for generating a negative pressure in the central chamber and drawing fluid into the central chamber via the assembly, and for generating a positive pressure in the central chamber and pumping fluid out of the central chamber via the assembly; a position sensor connected to the assembly, wherein the position sensor determines a position change of the assembly; and a processor operably connected to the position sensor for receiving the position change of the assembly, and the processor being operable to determine an air content of a sample fluid in the central chamber based on the positional change of the assembly. - View Dependent Claims (59, 60, 61, 62, 63, 64, 65, 66, 67, 68, 69, 70, 71, 72, 73, 74, 75, 76)
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Specification