Fluid flow monitoring method and system
First Claim
1. A system for monitoring the pressure of parenteral fluid in a fluid delivery system which includes a pump, tubing for transmitting pumped fluid to a cannula adapted to be inserted into a patient'"'"'s blood vessel, the pressure monitoring system comprising:
- (a) means to control the rate of fluid flow through the delivery system to the patient at a predetermined low flow rate (FLow) and at a predetermined high flow rate (FHi);
(b) means to sense the fluid pressure within the fluid delivery system;
(c) means to determine the difference in fluid pressure within the fluid delivery system during periods of the predetermined low flow rate and during period of the predetermined high flow rate;
(d) means to determine the difference between the predetermined high flow rate and the predetermined low flow rate;
(e) means to determine the resistance (R) of the fluid delivery system to fluid flow therethrough from the ratio of the fluid pressure difference to the fluid flow rate difference;
(f) means to calculate a pressure limit (PLim) from the product of resistance (R) and the high flow rate (FHi);
(g) means to compare the fluid pressure sensed within the fluid delivery system during a monitoring period with the calculated pressure limit (PLim); and
(h) means to generate an alarm signal when the pressure sensed exceeds the calculated pressure limit.
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Accused Products
Abstract
The invention is directed to a fluid flow monitoring method and system for parenteral fluid delivery systems for use in situations, such as with sedentary patients, when wide pressure variations are not expected. The resistance of the fluid delivery system is determined from the ratio of pressure differences at high and low fluid flow rates to differences in the high and low fluid flow rates. The resistance is used to develop a pressure limit from the sum of the pressure at low fluid flow rates and the product of the resistance and the high fluid flow rate. The pressure limit is compared with the pressure monitored and if the pressure monitored exceeds the calculated pressure limit, an alarm is actuated to warn medical personnel of an occlusion or other fluid flow fault. Additionally, if the noise level (pressure) excess predetermined limits during the periods of low and high fluid flow, the pressure monitoring is terminated.
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Citations
21 Claims
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1. A system for monitoring the pressure of parenteral fluid in a fluid delivery system which includes a pump, tubing for transmitting pumped fluid to a cannula adapted to be inserted into a patient'"'"'s blood vessel, the pressure monitoring system comprising:
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(a) means to control the rate of fluid flow through the delivery system to the patient at a predetermined low flow rate (FLow) and at a predetermined high flow rate (FHi); (b) means to sense the fluid pressure within the fluid delivery system; (c) means to determine the difference in fluid pressure within the fluid delivery system during periods of the predetermined low flow rate and during period of the predetermined high flow rate; (d) means to determine the difference between the predetermined high flow rate and the predetermined low flow rate; (e) means to determine the resistance (R) of the fluid delivery system to fluid flow therethrough from the ratio of the fluid pressure difference to the fluid flow rate difference; (f) means to calculate a pressure limit (PLim) from the product of resistance (R) and the high flow rate (FHi); (g) means to compare the fluid pressure sensed within the fluid delivery system during a monitoring period with the calculated pressure limit (PLim); and (h) means to generate an alarm signal when the pressure sensed exceeds the calculated pressure limit. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11)
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12. A method for monitoring the pressure of parenteral fluid in a fluid delivery system which includes a pump, tubing for transmitting pumped fluid to a cannula adapted to be inserted into a patient'"'"'s blood vessel, the method of monitoring the pressure comprising:
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(a) controlling the rate of fluid through the delivery system to the patient at a predetermined low flow rate (FLow) and at a predetermined high flow rate (FHi); (b) sensing the fluid pressure within the fluid delivery system; (c) determining the difference in fluid pressure within the fluid delivery system during the predetermined low flow rate and during the predetermined high flow rate; (d) determining the difference between predetermined the high flow rate and the predetermined low flow rate; (e) determining the resistance (R) of the fluid delivery system to fluid flow therethrough from the ratio of the pressure difference to the fluid flow rate difference; (f) calculating the pressure limit (PLim) from the product of the resistance (R) and the high flow rate (FHi); (g) comparing the fluid pressure (PHi) sensed within the fluid delivery system during a monitoring period with the calculated pressure limit (PLim); and (h) generating an alarm signal when the pressure sensed exceeds the calculated pressure limit. - View Dependent Claims (13, 14, 15, 16, 17, 18, 19, 20, 21)
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Specification