SYSTEM AND METHOD FOR DETECTING OCCLUSION USING FLOW SENSOR OUTPUT

• US 20090177148A1
• Filed: 01/08/2008
• Published: 07/09/2009
• Est. Priority Date: 01/08/2008
• Status: Active Grant

• Current Assignee: Baxter Healthcare SA (Baxter International Inc.), Baxter International Inc.
• Original Assignee: Baxter Healthcare SA (Baxter International Inc.), Baxter International Inc.
• Inventors: Yardimci, Atif, DelCastilio, Jorge A.
• Granted Patent: US 7,880,624 B2
• Time in Patent Office: Days
• US Class Current: 604/67
• CPC Class Codes: A61M 2205/3331 Pressure; Flow
• CPC Class Codes: A61M 2205/3334 Measuring or controlling the flow rate
• CPC Class Codes: A61M 5/14212 Pumping with an aspiration and an expulsion action
• CPC Class Codes: A61M 5/16831 Monitoring, detecting, signalling or eliminating infusion flow anomalies low-level float-valves causing cut-off A61M5/40; indicating or recording presence, absence or direction of flow in general G01P13/0066

Abstract

A method and system for detecting an inclusion within an infusion system. The method includes monitoring an output signal of a flowrate sensor as fluid flows through an infusion system. The output signal is then converted with a noise reduction filter to obtain a filtered output signal. The filtered output signal is compared to a threshold value and an alarm is activated if the filtered output signal falls below a desired threshold, thereby indicating an occlusion within the infusion system.

Claims

1. A method of detecting an occlusion within an infusion system comprising:

monitoring an output signal from a flowrate sensor as fluid flows through an infusion system;

filtering the output signal with a noise reduction filter to obtain a filtered output signal; and

activating an alarm if the filtered output signal falls below a threshold level.

2. The method of claim 1, which includes filtering the output signal with a backward averaging filter.

3. The method of claim 1, which includes filtering the output signal with a ten second averaging filter.

4. The method of claim 1, which includes continuously monitoring and filtering the output signal with the noise reduction filter.

5. The method of claim 1, which includes acquiring a baseline of the output signal of the flowrate sensor, and filtering the baseline with an averaging filter to calculate a baseline average, and calculating the threshold level as a function of the baseline average.

6. The method of claim 5, which includes calculating the standard deviation of the baseline average and calculating the threshold level by subtracting the standard deviation from the baseline average.

7. The method of claim 5, which includes calculating the threshold level as a percentage of the baseline average.

8. The method of claim 5, which includes filtering the baseline with a backward averaging filter.

9. The method of claim 5, which includes filtering the baseline with a ten second averaging filter.

10. The method of claim 1, which includes monitoring an analog output signal from the flowrate sensor.

11. A system configured to perform the steps of claim 1.

12. A method of detecting an occlusion within an infusion system, comprising:

monitoring an output signal from a flowrate sensor as a pulsatile fluid flow having a frequency flows through the infusions system;

acquiring a data set that includes the output signal as a function of time;

filtering the data set with a noise rejection filter to produce a filtered data set;

performing spectra analysis on the filtered data set to determine strength of the output signal in a frequency domain;

calculating a signal strength for a frequency range that correlates to the frequency of the pulsatile fluid flow; and

comparing the signal strength of the range to at least one threshold level to determine if an occlusion is present within the infusion system.

13. The method of claim 12, which includes calculating the signal strength of the range of frequency by integrating power spectra in a frequency domain for the frequency range and computing an energy metric.

14. The method of claim 12, which includes filtering the date set with a low-pass or a high-pass frequency filter.

15. The method of claim 12, which includes performing the spectra analysis by performing Fast Fourier Transform on the filtered data set.

16. The method of claim 12, which includes activating an alarm if the signal strength of the range of frequency is above the threshold level.

17. The method of claim 12, which includes activating an alarm if the signal strength of the range of frequency is below the threshold level.

18. The method of claim 12, which includes activating an alarm if the signal strength is above an upper threshold or below a lower threshold level.

19. A system configured to perform the steps of claim 12.

20. An infusion system, comprising:

a fluid pathway between a fluid source and a patient;

a flowrate sensor disposed along the fluid pathway, the flowrate sensor operable to produce an output signal;

a processing device in communication with and receiving the output signal from the flowrate sensor, the processing device configured to apply a filter to the output signal to produce a filtered output signal; and

an alarm operable with the processing device to indicate when the filtered output signal falls below or rises above a predetermined threshold value.

21. The infusion system of claim 20, wherein the flowrate sensor is configured to produce an analog output signal.

22. The infusion system of claim 20, wherein the filter is of a type selected from the group consisting of:

a backend averaging filter, a ten second averaging filter, a central averaging filter and a weighted averaging filter.