Patent US4898576A successfully refreshed from Google Patents.
US4898576A
Expired / Lapsed
US
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Intravenous fluid flow monitor
Assignee: CareFusion 303 Inc
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Filing: 1988-08-22
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Granted: 1990-02-06
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Expires: 2008-08-22
Abstract
Abstract An improved system for monitoring the fluid flow through a fluid delvery system to a patient wherein the fluid flow rate is varied in a predetermined sequential manner. Corresponding changes in pressure in the line connecting the vein of a patient and the pump are detected and are used to derive signals indicative of the resistance or impedance in the line, which in turn can be used to determine whether the vein is normal, whether it is phlebitic, whether it is occluded, whether infiltration of the canula into the patient's soft tissue has occurred, or whether the continuity of tubing to the vein has been interrupted.
Inventors
- 👤 James H. Philip
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-30 13:06
CPC Classifications
A; A61; A61M; A61M5/00; A61M5/14; A61M5/168; A61M5/16831; A61M5/16854; A61M5/16859
Claims Analysis
Total Claims: 25
Claim 1
Independent Claim
97 words
A system for monitoring the flow of fluid through a fluid delivery system to a patient comprising: (a) means for monitoring fluid pressure in the fluid delivery system supplying fluid to a patient; (b) means for controlling the fluid flow through the fluid delivery system at sequentially different flow rates in a predetermined manner; (c) means responsive to the sensed pressures and the sequentially different fluid flow rates, for determining resistance to fluid flow in the fluid delivery system; and (d) means for comparing the determined resistance with predetermined limits and for generating output signals responsive thereto.
Claim 2
Independent Claim
97 words
A system for monitoring the flow of fluid through a fluid delivery system to a patient comprising: (a) means for monitoring fluid pressure in the fluid delivery system supplying fluid to a patient; (b) means for controlling the fluid flow through the fluid delivery system at sequentially different flow rates in a predetermined manner; (c) means responsive to the sensed pressures and the sequentially different fluid flow rates, for determining resistance to fluid flow in the fluid delivery system; and (d) means for comparing the determined resistance with predetermined limits and for generating output signals responsive thereto.
Claim 3
Dependent Claim
34 words
The system of claim 1, wherein the means for determining the resistance to fluid flow in the fluid delivery system and the means for comparing the determined resistance to predetermined limits is a microprocessor.
Claim 4
Dependent Claim
38 words
The system of claim 2, wherein the microprocessor further comprises means for monitoring the time rate of change of pressure in the fluid delivery system which is responsive to sequential differences in the flow rate of the fluid.
Claim 5
Dependent Claim
38 words
They system of claim 3 wherein the microprocessor includes means to calculate from the time rate change of pressure in the fluid delivery system the mean transit time of sequential differences in the flow rate of the fluid.
Claim 6
Dependent Claim
45 words
The system of the claim 3 wherein the microprocessor includes means to calculate from the time rate of change of pressure in the fluid delivery system a time constant which is responsive to sequential differences in the fluid flow rate in the fluid delivery system.
Claim 7
Dependent Claim
48 words
The system of claim 2, wherein the means for monitoring the pressure in the fluid delivery system is a pressure transducer outputting an analog signal, and the system further comprises analog-to-digital converter means for conversion of the analog signal to a digital signal for supply to the microprocessor.
Claim 8
Dependent Claim
32 words
The system of claim 2, wherein the microprocessor includes means to calculate resistance from the changes in pressure with respect to the sequential differences in flow rate, to provide a resistance value.
Claim 9
Dependent Claim
23 words
The monitor of claim 7, wherein the microprocessor further comprises means for determining the rate of change of pressure with respect to time.
Claim 10
Dependent Claim
25 words
The system of claim 1, wherein the fluid flow control means includes means to generate variations in fluid flow rates having a predetermined frequency spectrum.
Claim 11
Dependent Claim
30 words
The system of claim 9, wherein the microprocessor comprises means for taking the Fourier transform of variations in the pressure which are responsive to the variations in the flow rate.
Claim 12
Dependent Claim
21 words
The system of claim 9, wherein said microprocessor further comprises means for calculating the time derivative of changes in the pressure.
Claim 13
Dependent Claim
59 words
The system of claim 1, wherein the means for supplying fluid at controllable flow rates comprises means for causing the flow rates to be varied in a manner having a defined frequency component, and wherein the means for determining resistance to flow comprises means for analyzing the variations in pressure which are responsive to the variations in flow rates.
Claim 14
Independent Claim
90 words
A method for monitoring the flow of fluid through a fluid delivery system to a patient comprising: (a) monitoring fluid pressure in the fluid delivery system supplying fluid to a patient; (b) controlling the fluid flow through the fluid delivery system at sequentially different flow rates in a predetermined manner; (c) determining resistance to fluid flow in the fluid delivery system in response to the sensed pressure and to the sequentially different fluid flow rates; and (d) comparing the determined resistance to predetermined limits and generating output signals responsive thereto.
Claim 15
Independent Claim
90 words
A method for monitoring the flow of fluid through a fluid delivery system to a patient comprising: (a) monitoring fluid pressure in the fluid delivery system supplying fluid to a patient; (b) controlling the fluid flow through the fluid delivery system at sequentially different flow rates in a predetermined manner; (c) determining resistance to fluid flow in the fluid delivery system in response to the sensed pressure and to the sequentially different fluid flow rates; and (d) comparing the determined resistance to predetermined limits and generating output signals responsive thereto.
Claim 16
Dependent Claim
35 words
The method of claim 13 including calculating the rate of change of pressure in the fluid delivery system with respect to time which is responsive to the sequential differences in flow rate of the fluid.
Claim 17
Dependent Claim
30 words
The method of claim 14 wherein the changes in pressure with respect to the sequential variations in flow rate are determined in order to determine a resistance to fluid flow.
Claim 18
Dependent Claim
15 words
The method of claim 15, wherein the time rate of change of pressure is calculated.
Claim 19
Dependent Claim
22 words
The method of claim 13 including calculating the mean transit time of the sequential differences in the flow rate of the fluid.
Claim 20
Dependent Claim
31 words
The method of claim 13 including calculating a time constant for changes in the pressure which is responsive to the sequential differences in the flow rate in the fluid delivery system.
Claim 21
Dependent Claim
23 words
The method of claim 14 including generating an analog signal representing the monitored pressure and converting the analog signal to a digital signal.
Claim 22
Dependent Claim
17 words
The method of claim 13, wherein the sequential variations in flow rates have a predetermined frequency spectrum.
Claim 23
Dependent Claim
25 words
The method of claim 20, including determining the Fourier transforms of variations in the pressure which are responsive to sequential variations in the flow rate.
Claim 24
Dependent Claim
16 words
The method of claim 21, wherein the time derivative of changes in the pressure is calculated.
Claim 25
Dependent Claim
49 words
The method of claim 20, wherein the fluid is supplied at controllable flow rates which are sequentially varied in a manner having a defined frequency content, and resistance to flow is determined by analyzing the sequential variations in pressure which are responsive to the sequential variations in flow rates.
References Cited (Backward Citations)
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1993-02-05 | 1993-08-07 | 1994-02-06 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1997-02-05 | 1997-08-07 | 1998-02-06 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 2001-02-05 | 2001-08-07 | 2002-02-06 | $7700.00 | Window Closed / Lapsed |