Device, method, and system for monitoring the delivery of fluids through a drip chamber

• US 9,199,036 B2
• Filed: 02/24/2014
• Issued: 12/01/2015
• Est. Priority Date: 02/25/2013
• Status: Expired due to Fees

• Current Assignee: Shift Labs, Inc. (Augeo Affinity Marketing, Inc.)
• Original Assignee: Shift Labs, Inc. (Augeo Affinity Marketing, Inc.)
• Inventors: Kolko, Beth Elise, Lafleur, Lisa Kathryn, Flickenger, Robert John, Hu, Jennifer, Intlekofer, Koji, Rutschman, Phillip Edward
• Primary Examiner(s): THOMPSON, JEWEL VERGIE
• Application Number:
  US14/188,669
• Publication Number:
  US 20140283620A1
• Time in Patent Office: 645 Days
• Field of Search: 738/614.1, 340/606, 340/603, 600/344, 604/253, 604/246
• US Class Current: 1/1
• CPC Class Codes: A61M 2205/18 with alarm
• CPC Class Codes: A61M 2205/3306 Optical measuring means
• CPC Class Codes: A61M 2205/3553 remote, e.g. between patient's home and doctor's office
• CPC Class Codes: A61M 2205/3584 using modem, internet or bluetooth
• CPC Class Codes: A61M 2205/50 with microprocessors or computers
• CPC Class Codes: A61M 2205/502 User interfaces, e.g. screens or keyboards
• CPC Class Codes: A61M 2205/505 Touch-screens; Virtual keyboard or keypads; Virtual buttons; Soft keys; Mouse touches
• CPC Class Codes: A61M 2205/52 with memories providing a history of measured variating parameters of apparatus or patient
• CPC Class Codes: A61M 2205/581 by audible feedback
• CPC Class Codes: A61M 2205/583 by visual feedback
• CPC Class Codes: A61M 2205/8206 battery-operated
• CPC Class Codes: A61M 2205/8293 Solar
• CPC Class Codes: A61M 5/1411 Drip chambers A61M5/162, A61M5/1689, A61M5/40 take precedence
• CPC Class Codes: A61M 5/1689 Drip counters
• CPC Class Codes: G01F 1/05 by using mechanical effects
• CPC Class Codes: G01F 1/704 using marked regions or existing inhomogeneities within the fluid stream, e.g. statistically occurring variations in a fluid parameter G01F1/76, G01F25/00 take precedence
• CPC Class Codes: G16H 20/17 delivered via infusion or injection

Abstract

A device, method, and system are provided for monitoring the delivery of fluids through a drip chamber. The device includes an electromagnetic radiation (EMR) source and an EMR detector. A device body is employed to position the source and detector about the drip chamber so that the source and detector define an optical path across the drip chamber. A processor device is employed to detect fluid drops from differences between detector signal values separated by a lag time. The flow rate is determined from a drip factor and the detection of multiple drops. In the context of delivering intravenous (IV) fluids, a battery powered handheld monitoring device that includes the source, detector, device body, and processor device may be affixed to a drip chamber included in an infusion set. The device includes a user interface, including buttons, a display, and an audio speaker, for the input and output of information.

Claims

1. A flow rate monitoring device for monitoring a flow rate of fluid through a drip chamber, the device comprising:

(a) a source enabled to emit electromagnetic radiation (EMR);

(b) a detector enabled to generate a detector signal;

(c) a device body configured and arranged to position the source and the detector about at least one outer surface of the drip chamber such that the source and the detector define an optical path across the drip chamber, wherein fluid between the source and the detector inhibits EMR travelling along the optical path; and

(d) a processor device that executes instructions that perform actions, comprising;

i. detecting a fluid drop based on at least a difference between a plurality of detector signal values temporally separated by a predetermined lag time; and

ii. determining the flow rate of fluid based on at least a predetermined drip factor and detecting a plurality of fluid drops.

2. The flow rate monitoring device of claim 1, wherein detecting the fluid drop is further based on a comparison of a plurality of temporally ordered difference values, wherein each of the plurality of difference values correspond to differences in the plurality of detector signals that are temporally separated by the lag time.

3. The flow rate monitoring device of claim 1, wherein the actions further include vetoing a detection of a second fluid drop when a temporal difference between the detection of the second fluid drop and a detection of a first fluid drop is less than a predetermined lockout time.

4. The flow rate monitoring device of claim 1, wherein detecting the fluid drop further comprises:

(a) generating a drop waveform based on detector signal values sampled at a plurality of temporally ordered times, wherein the drop waveform is modulated by the fluid drop;

(b) generating a lag time difference waveform based on at least the lag time and a plurality of differences of the drop waveform corresponding to different times; and

(c) detecting the fluid drop based on at least a signal included in the lag time difference waveform.

5. The flow rate monitoring device of claim 1, wherein the source is a light emitting diode (LED).

6. The flow rate monitoring device of claim 1, wherein the detector is a photodiode.

7. The flow rate monitoring device of claim 1, wherein the source is further enabled to emit EMR within a wavelength window, wherein wavelengths within the wavelength window are longer than visible light wavelengths and a sensitivity of the detector is greater for at least a portion of the wavelengths within the wavelength window than for visible light wavelengths.

8. The flow rate monitoring device of claim 1, wherein the actions further include:

(a) detecting a first fluid drop at a first detection time;

(b) adding the first detection time to a drop history buffer, wherein the drop history buffer includes at least a plurality of other detection times and each of the other detection times corresponds to a previously detected fluid drop;

(c) removing at least one of the other detection times from the drop history buffer; and

(d) determining an average drop rate based on at least the detection times included in the history buffer.

9. The flow rate monitoring device of claim 8, wherein the actions further include:

(a) determining a drip stability based on a comparison of a plurality of temporal distances between the detection times included in the drop history buffer.

10. The flow rate monitoring device of claim 1, wherein the actions further include at least one of:

(a) displaying the flow rate of fluid;

(b) providing an alert when the flow rate of fluid is outside of a predetermined range;

(c) providing an alert when a drip stability is less than a predetermined threshold; and

(d) providing an alert when an average drop rate is outside of another predetermined range.

11. The flow rate monitoring device of claim 1, wherein the device body includes a clip configured and arranged for at least a closed state, wherein the closed state forms a cavity within the device body, wherein the source and detector are in opposition along at least one inner surface of the cavity such that the cavity may receive at least a portion of the drip chamber forming the optical path across the drip chamber.

12. The flow rate monitoring device of claim 11, wherein at least a portion of the inner surface of the cavity includes a textured feature for producing friction between the inner surface of the cavity and the outer surface of the drip chamber.

13. The flow rate monitoring device of claim 1, wherein the device body includes a trench, wherein the source and detector are in opposition along at least one inner surface of the trench and the trench is configured and arranged for affixing the device to the drip chamber such that at least a portion of the drip chamber is visible to a user, providing visual feedback of the detected fluid drops.

14. The flow rate monitoring device of claim 13, wherein the at least one inner surface of the trench includes at least one of:

(a) a textured portion;

(b) a gripping cam; and

(c) a compressible gripping material.

15. The flow rate monitoring device of claim 1, wherein the device further includes a battery.

16. The flow rate monitoring device of claim 1, wherein power to at least one of the detector and the source is pulsed.

17. A method for monitoring a flow rate of fluid through a drip chamber, the method comprising actions of:

(a) positioning a source and a detector about at least one outer surface of the drip chamber such that the source and the detector define an optical path across the drip chamber, wherein the source is enabled to emit electromagnetic radiation (EMR) and the detector is enabled to generate a detector signal, and wherein fluid between the source and the detector inhibits EMR travelling along the optical path;

(b) detecting a fluid drop based on at least a difference between a plurality of detector signal values temporally separated by a predetermined lag time; and

(c) determining the flow rate of fluid based on at least a predetermined drip factor and detecting a plurality of fluid drops.

18. The method of claim 17, wherein detecting the fluid drop is further based on a comparison of a plurality of temporally ordered difference values, wherein each of the plurality of difference values correspond to differences in the plurality of detector signals that are temporally separated by the lag time.

19. The method of claim 17, wherein the actions further include vetoing a detection of a second fluid drop when a temporal difference between the detection of the second fluid drop and a detection of a first fluid drop is less than a predetermined lockout time.

20. The method of claim 17, wherein detecting the fluid drop further includes:

(a) generating a drop waveform based on detector signal values sampled at a plurality of temporally ordered times, wherein the drop waveform is modulated by the fluid drop;

(b) generating a lag time difference waveform based on at least the lag time and a plurality of differences of the drop waveform corresponding to different times; and

(c) detecting the fluid drop based on at least a signal included in the lag time difference waveform.

21. The method of claim 17, wherein the source is a light emitting diode (LED).

22. The method of claim 17, wherein the detector is a photodiode.

23. The method of claim 17, wherein the source is further enabled to emit EMR within a wavelength window, wherein wavelengths within the wavelength window are longer than visible light wavelengths and a sensitivity of the detector is greater for at least a portion of the wavelengths within the wavelength window than for visible light wavelengths.

24. The method of claim 17, wherein the actions further include:

(a) detecting a first fluid drop at a first detection time;

(b) adding the first detection time to a drop history buffer, wherein the drop history buffer includes at least a plurality of other detection times and each of the other detection times corresponds to a previously detected fluid drop;

(c) removing at least one of the other detection times from the drop history buffer; and

(d) determining an average drop rate based on at least the detection times included in the history buffer.

25. The method of claim 24, wherein the actions further include:

(a) determining a drip stability based on a comparison of a plurality of temporal distances between the detection times included in the drop history buffer.

26. The method of claim 24, wherein the actions further include at least one of:

(a) displaying the flow rate of fluid;

(b) providing an alert when the flow rate of fluid is outside of a predetermined range;

(c) providing an alert when a drip stability is less than a predetermined threshold; and

(d) providing an alert when an average drop rate is outside of another predetermined range.

27. The method of claim 17, wherein the source and the detector are positioned such that at least a portion of the drip chamber is visible to a user, providing visual feedback of the detected fluid drops.

28. A system for monitoring a flow rate of fluid through a drip chamber, the system comprising:

(a) a monitoring device comprising;

i. a source enabled to emit electromagnetic radiation (EMR);

ii. a detector enabled to generate a detector signal; and

iii. a device body configured and arranged to position the source and the detector about at least one outer surface of the drip chamber such that the source and the detector define an optical path across the drip chamber, wherein fluid between the source and the detector inhibits EMR travelling along the optical path; and

(b) a processor device that executes instructions that perform actions, comprising;

i. detecting a fluid drop based on at least a difference between a plurality of detector signal values temporally separated by a predetermined lag time; and

ii. determining the flow rate of fluid based on at least a predetermined drip factor and detecting a plurality of fluid drops.

29. The system of claim 28, wherein detecting the fluid drop is further based on a comparison of a plurality of temporally ordered difference values, wherein each of the plurality of difference values correspond to differences in the plurality of detector signals that are temporally separated by the lag time.

30. The system of claim 29, wherein the actions further include vetoing a detection of a second fluid drop when a temporal difference between the detection of the second fluid drop and a detection of a first fluid drop is less than a predetermined lockout time.

31. The system of claim 28, wherein the source and the detector are positioned such that at least a portion of the drip chamber is visible to a user, providing visual feedback of the detected fluid drops.

32. The system of claim 28, wherein detecting the fluid drop further includes:

(a) generating a drop waveform based on detector signal values sampled at a plurality of temporally ordered times, wherein the drop waveform is modulated by the fluid drop;

(b) generating a lag time difference waveform based on at least the lag time and a plurality of differences of the drop waveform corresponding to different times; and

(c) detecting the fluid drop based on at least a signal included in the lag time difference waveform.