Devices, systems, and methods for measuring blood loss

Patent metadata

Field	Value
Publication number	US-10041960-B2
Application number	US-201414890098-A
Country	US
Kind code	B2
Filing date	May 9, 2014
Priority date	May 10, 2013
Publication date	Aug 7, 2018
Grant date	Aug 7, 2018

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.

First claim

What is claimed is:

1. A blood measurement device for determining the amount of blood of a subject within a fluid sample, the fluid sample having a volume and being positioned within a container having a vertical axis, the blood measurement device comprising:
at least one light source configured to selectively generate light at a first wavelength and at a second wavelength different from the first wavelength;
at least one light detector, wherein the at least one light source and the at least one light detector are configured for positioning in an operative position within the container, wherein, in the operative position, the at least one light source is configured to transmit light at a plurality of locations spaced along the vertical axis of the container and the at least one light detector is configured to receive at least a portion of the light generated by the at least one light source, and wherein upon positioning of the at least one light source and the at least one light detector in the operative position, the at least one light detector 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 light detector, wherein the processor is configured to receive the first and second signals from the at least one light detector, and wherein, based upon the received first and second signals, the processor is configured to repeatedly determine the concentration of hemoglobin within the fluid sample as blood from the subject is added to the fluid sample,
wherein the processor is configured to determine a current volume of blood within the fluid sample based upon a previously measured hemoglobin concentration of the subject, the determined hemoglobin concentration within the fluid sample, and the volume of 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 , wherein each light source of the at least one 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, and wherein each LED of the plurality of LEDs is configured for selective activation.

5. 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=( A 1 −A 2 )* k 1 +k 2 , where:
Hgb=the total hemoglobin concentration within the fluid sample;
A 1 =the measured absorbance of the light within the fluid sample the first wavelength;
A 2 =the measured absorbance of the light within the fluid sample at the second wavelength;
k 1 =the calibration coefficient for light at the first wavelength; and
k 2 =the calibration coefficient for light at the second wavelength.

6. 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.

7. The blood measurement device of claim 1 , wherein the at least one light detector comprises an array of a plurality of light detectors, and wherein each light detector of the array of light detectors is configured to produce a transmittance signal indicative of the transmittance of light measured by the light detector, and wherein the processor is configured to receive the transmittance signal from each light detector.

8. The blood measurement device of claim 7 , wherein the processor is configured to associate the transmittance signal produced by each respective light detector of the array of light detectors with a position relative to the vertical axis of the container, and wherein the processor is configured to determine the highest position corresponding to a light detector of the array of light detectors that produced a transmittance signal indicative of a transmission of light within the fluid sample.

9. The blood measurement device of claim 8 , wherein the highest position corresponding to a light detector of the array of light detectors that produced a transmittance signal indicative of a transmission of light within the fluid sample 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.

10. The blood measurement device of claim 1 , 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( t ), 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).

11. The blood measurement device of claim 10 , wherein the processor is configured to receive at least one input indicative of a previously measured hemoglobin concentration of the blood of the subject.

12. The blood measurement device of claim 10 , wherein the processor is configured to receive at least one input indicative of a previously estimated blood loss of the subject.

13. The blood measurement device of claim 1 , wherein the processor is configured to determine the volume of blood within the fluid sample according to the equation:
EBL( t )=EBL( t− 1)+[ V C ( t )− V C ( t− 1)]*[Hgb C ( t )/Hgb P ( t− 1)], 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); and
Hgb P (t−1)=Hemoglobin Concentration of Blood as it Left the Subject at previously measured time (t−1).

14. The blood measurement device of claim 1 , wherein the at least one light source is coupled to a base element that is configured for selective insertion within the fluid sample, and wherein the at least one light source is configured to transmit light at a pluralit

Assignees

• Univ Utah Res Found

Inventors

• Macintyre Annette
• Brewer Lara
• Wendelken Suzanne
• Tate Quinn
• Hoehne Soeren

Classifications

• A61B5/02042 Primary

  Determining blood loss or bleeding, e.g. during a surgical procedure · CPC title

• G01N33/49

  Blood {(chemical methods for determining blood cell populations G01N33/5094; chemical analysis of blood groups or blood types G01N33/80)} · CPC title

• A61B5/14546

  for measuring analytes not otherwise provided for, e.g. ions, cytochromes · CPC title

• G01N2333/805

  Haemoglobins; Myoglobins · CPC title

• A61B5/1455

  using optical sensors, e.g. spectral photometrical oximeters · CPC title