Devices, Systems, and Methods for Measuring Blood Loss

• US 20160123998A1
• Filed: 05/09/2014
• Published: 05/05/2016
• Est. Priority Date: 05/10/2013
• Status: Active Grant

• Current Assignee: University of Utah Research Foundation (State of Utah)
• Original Assignee: University of Utah Research Foundation (State of Utah)
• Inventors: Brewer, Lara, Hoehne, Soeren, MacIntyre, Annette, Wendelken, Suzanne, Tate, Quinn
• Granted Patent: US 10,041,960 B2
• Time in Patent Office: Days
• US Class Current: 1/1
• CPC Class Codes: A61B 5/02042 Determining blood loss or bleeding, e.g. during a surgical procedure
• CPC Class Codes: A61B 5/14546 for measuring analytes not otherwise provided for, e.g. ions, cytochromes
• CPC Class Codes: A61B 5/1455 using optical sensors, e.g. spectral photometrical oximeters
• CPC Class Codes: A61M 1/777 Determination of loss or gain of body fluids due to suction-irrigation, e.g. during surgery
• CPC Class Codes: G01N 21/31 Investigating relative effect of material at wavelengths characteristic of specific elements or molecules, e.g. atomic absorption spectrometry G01N21/72 takes precedence
• CPC Class Codes: G01N 2333/805 Haemoglobins; Myoglobins
• CPC Class Codes: G01N 33/49 Blood chemical methods for determining blood cell populations G01N33/5094; chemical analysis of blood groups or blood types G01N33/80
• CPC Class Codes: G01N 33/721 Haemoglobin

Abstract

Devices, systems, and methods for measuring the blood loss of a subject during a medical procedure. Blood and other fluids are received within a container, and a blood measurement device determines the hemoglobin concentration of the fluid within the container. The blood measurement device can also calculate the estimated blood loss of the subject based upon the determined hemoglobin concentration and the volume of the fluid within the container and the patient'"'"'s hemoglobin.

Claims

1. A blood measurement device for determining the amount of blood of a subject within a fluid sample, the fluid sample having a volume, the blood measurement device comprising:

a light source configured to selectively generate light at a first wavelength and at a second wavelength different from the first wavelength;

at least one photodetector, wherein the light source and the at least one photodetector are configured for positioning in an operative position, wherein, in the operative position, the at least one photodetector is configured to receive at least a portion of the light generated by the light source, and wherein upon positioning of the light source and the at least one photodetector in the operative position, the at least one photodetector is configured to produce a first signal indicative of the absorbance of the fluid sample at the first wavelength and a second signal indicative of the absorbance of the fluid sample at the second wavelength; and

a processor operatively coupled to the at least one photodetector, wherein the processor is configured to receive the first and second signals from the at least one photodetector, and wherein, based upon the received first and second signals, the processor is configured to determine the concentration of hemoglobin within the fluid sample.

2. The blood measurement device of claim 1, wherein the first wavelength ranges from about 500 nm to about 600 nm, and wherein the second wavelength ranges from about 850 nm to about 900 nm.

3. The blood loss measurement device of claim 1, wherein the first wavelength is about 525 nm, and wherein the second wavelength is about 870 nm.

4. The blood measurement device of claim 1, further comprising a base element having first and second opposed members, wherein the first and second opposed members at least partially define a sample chamber configured to receive a portion of the fluid sample.

5. The blood measurement device of claim 4, wherein the light source is operatively coupled to the first member of the base element, and wherein the at least one photodetector is operatively coupled to the opposed second member of the base element.

6. The blood measurement device of claim 5, wherein the base element, the light source, and the at least one photodetector are configured for selective insertion within the fluid sample as a unitary structure.

7. The blood measurement device of claim 6, wherein the base element is configured for selective attachment to a suction canister.

8. The blood measurement device of claim 1, further comprising a base element, wherein the light source is operatively coupled to the base element.

9. The blood measurement device of claim 8, wherein the base element and the light source are configured for selective insertion within the fluid sample as a unitary structure.

10. The blood measurement device of claim 9, wherein the base element is configured for selective attachment to a container.

11. The blood measurement device of claim 1, wherein the at least one photodetector comprises an array of a plurality of photodetectors.

12. The blood measurement device of claim 11, wherein the light source comprises a plurality of light emitting diodes (LEDs), wherein at least one LED of the plurality of LEDs is configured to emit light at the first wavelength, and wherein at least one LED of the plurality of LEDs is configured to emit light at the second wavelength.

13. The blood measurement device of claim 12, wherein each LED of the plurality of LEDs is configured for selective activation.

14. The blood measurement device of claim 11, wherein the array of photodetectors is radially spaced from the light source by a distance ranging from about 0.05 mm to about 0.2 mm.

15. The blood measurement device of claim 12, further comprising a plurality of pairs of opposed optical fibers, each pair of optical fibers comprising a first optical fiber operatively coupled to a corresponding LED of the plurality of LEDs and a second optical fiber operatively coupled to a corresponding photodetector of the plurality of photodetectors, wherein the plurality of opposed pairs of optical fibers are configured for selective insertion within the fluid sample, and wherein in the operative position, the plurality of photodetectors and the plurality of LEDs are not in fluid communication with the fluid sample.

16. The blood measurement device of claim 15, wherein each optical fiber of the plurality of pairs of opposed optical fibers comprises a receiving end and an opposed transmitting end, wherein the receiving end of the first optical fiber of each pair of optical fibers is configured to receive light from a corresponding LED of the plurality of LEDs, wherein the transmitting end of the first optical fiber of each pair of optical fibers is configured to transmit received light within the fluid sample, wherein the receiving end of the second optical fiber of each pair of optical fibers is configured to receive light transmitted by the transmitting end of an opposed first optical fiber, wherein the transmitting end of the second optical fiber of each pair of optical fibers is configured to transmit the received light to a corresponding photodetector of the plurality of photodetectors, and wherein the transmitting end of the first optical fiber of each pair of optical fibers is spaced from the receiving end of a corresponding second optical fiber by a selected distance.

17. The blood measurement device of claim 16, wherein the selected distance ranges from about 0.05 mm to about 0.2 mm.

18. The blood measurement device of claim 1, wherein the processor is configured to determine the concentration of hemoglobin within the fluid sample based upon the equation:

Hgb=(A₁−

A₂)*k₁+k₂, where;

Hgb=the total hemoglobin concentration within the fluid sample;

A₁=the measured absorbance of the light within the fluid sample the first wavelength;

A₂=the measured absorbance of the light within the fluid sample at the second wavelength;

k₁=the calibration coefficient for light at the first wavelength; and

k₂=the calibration coefficient for light at the second wavelength.

19. The blood measurement device of claim 1, wherein the processor is configured to receive at least one input indicative of the volume of the sample fluid.

20. The blood measurement device of claim 11, wherein the plurality of photodetectors are spaced relative to a vertical axis, wherein each photodetector of the array of photodetectors is configured to produce a transmittance signal indicative of the transmittance of light measured by the photodetector, and wherein the processor is configured to receive the transmittance signal from each photodetector.

21. The blood measurement device of claim 20, wherein the processor is configured to associate the transmittance signal produced by each respective photodetector of the array of photodetectors with a position of the photodetector relative to the vertical axis, and wherein the processor is configured to determine the highest position at which a photodetector of the array of photodetectors produced a transmittance signal indicative of a transmittance of less than 100%.

22. The blood measurement device of claim 21, wherein the highest position at which a photodetector of the array of photodetectors produced a transmittance signal indicative of a transmittance of less than 100% corresponds to the height of the fluid sample, and wherein the processor is configured to determine the volume of the fluid sample based upon the height of the fluid sample.

23. The blood measurement device of claim 19, wherein the processor is configured to determine the volume of blood within the fluid sample according to the equations:

EBL(t)=EBL(t−

1)+[V_C(t)−

V_C(t−

1)]*[Hgb_C(t)/Hgb_P(t−

1)]

EBV(t)≈

EBV(t−

1)+[V_IV(t)−

V_IV(t−

1)]−

[EBL(t)−

EBL(t−

1)]; and

Hgbp(t)=(EBV(t−

1)*Hgbp(t−

1)−

[Vc(t)−

Vc(t−

1)]*Hgbc(t))/EBV, where;

EBL(t)=Estimated Blood Loss at current time (t);

EBL(t−

1)=Estimated Blood Loss at previously measured time (t−

1);

V_C(t)=Volume of Fluid Sample within Suction Canister at current time (t);

V_C(t−

1)=Volume of Fluid Sample within Suction Canister at previously measured time (t−

1);

Hgb_C(t)=Hemoglobin Concentration of Fluid Sample within Suction Canister at current time (t);

Hgb_C(t−

1)=Hemoglobin Concentration of Fluid Sample within Suction Canister at previously measured time (t−

1);

Hgb_P(t)=Hemoglobin Concentration of Blood of the subject at current time (t);

Hgb_P(t−

1)=Hemoglobin Concentration of Blood as it Left the Subject at previously measured time (t−

1);

EBV(t)=Estimated Blood Volume of the subject at current time (t);

EBV(t−

1)=Estimated Blood Volume of the subject at previously measured time (t−

1);

V_IV(t)=Volume of IV Fluid within the subject at current time (t); and

V_IV(t−

1)=Volume of IV Fluid within the subject at previously measured time (t−

1).

24. The blood measurement device of claim 23, wherein the processor is configured to receive at least one input indicative of a previously measured hemoglobin concentration of the blood of the subject.

25. The blood measurement device of claim 23, wherein the processor is configured to receive at least one input indicative of a previously estimated blood loss of the subject.

26. A blood measurement system comprising:

a blood measurement device for determining the amount of blood of a subject within a fluid sample, the fluid sample having a volume, the blood measurement device comprising;

a light source configured to selectively generate light at a first wavelength and at a second wavelength different from the first wavelength;

at least one photodetector, wherein the light source and the at least one photodetector are configured for positioning in an operative position, wherein, in the operative position, the at least one photodetector is configured to receive at least a portion of the light generated by the light source, and wherein upon positioning of the light source and the at least one photodetector in the operative position, the at least one photodetector is configured to produce a first signal indicative of the absorbance of the fluid sample at the first wavelength and a second signal indicative of the absorbance of the fluid sample at the second wavelength; and

a processor operatively coupled to the at least one photodetector, wherein the processor is configured to receive the first and second signals from the at least one photodetector, and wherein, based upon the received first and second signals, the processor is configured to determine the concentration of hemoglobin within the fluid sample; and

a suction canister, the suction canister having an outer wall having an internal surface and an external surface, the internal surface of the outer wall defining an interior space configured to receive the fluid sample.

27. The blood measurement system of claim 26, wherein the light source is integrally formed with the suction canister.

28. The blood measurement system of claim 26, wherein the at least one photodetector is integrally formed with the suction canister.

29. The blood measurement system of claim 26, further comprising a drip counter configured for communication with an intravenous (IV) fluid delivery element, the drip counter being configured to produce a volume signal indicative of the volume of IV fluid dispensed from the IV fluid delivery element and a delivery rate signal indicative of the rate at which IV fluid is dispensed from the IV fluid delivery element, wherein the drip counter is positioned in operative communication with the processor such that the processor is configured to receive the volume signal and the delivery rate signal.

30. The blood measurement system of claim 26, wherein the processor is configured to receive at least one user input, wherein each user input is indicative of one of:

a volume of one or more intravenous (IV) fluids dispensed from an IV fluid delivery element; and

a rate at which the one or more IV fluids is dispensed from the IV fluid delivery element.

31. A method of measuring the amount of blood of a subject within a fluid sample, comprising:

operatively positioning a blood measurement device relative to a fluid sample, the blood measurement device comprising;

a light source configured to selectively generate light at a first wavelength and at a second wavelength different from the first wavelength;

at least one photodetector, wherein the light source and the at least one photodetector are configured for positioning in an operative position, wherein, in the operative position, the at least one photodetector is configured to receive at least a portion of the light generated by the light source, and wherein upon positioning of the light source and the at least one photodetector in the operative position, the at least one photodetector is configured to produce a first signal indicative of the absorbance of the fluid sample at the first wavelength and a second signal indicative of the absorbance of the fluid sample at the second wavelength; and

a processor operatively coupled to the at least one photodetector, wherein the processor is configured to receive the first and second signals from the at least one photodetector; and

using the processor of the blood measurement device to determine the concentration of hemoglobin within the fluid sample.

32. The method of claim 31, further comprising administering one or more reagents to the fluid sample, wherein the one or more reagents are configured to convert hemoglobin within the fluid sample into one of methemoglobin and sulphemoglobin.

33. The method of claim 31, further comprising delivering an anti-coagulant to the fluid sample.

34. The method of claim 33, wherein the anti-coagulant is heparin.