System and method for non-invasive monitoring of hematocrit concentration

Patent metadata

Field	Value
Publication number	US-12262991-B2
Application number	US-202117452190-A
Country	US
Kind code	B2
Filing date	Oct 25, 2021
Priority date	Jan 9, 2018
Publication date	Apr 1, 2025
Grant date	Apr 1, 2025

Abstract

A method of non-invasively monitoring hematocrit levels includes monitoring a first emission response to the light provided at the first excitation wavelength, wherein the first emission response is monitored at a first wavelength and monitoring a second emission response to the light provided at the first excitation wavelength, wherein the second emission response is monitored at a second wavelength. A ratiometric value is calculated based on a ratio of the first emission response to the second emission response, wherein the ratiometric value corresponds with hematocrit level of the patient.

First claim

The invention claimed is:

1. A system comprising:
a medical device comprising:
at least one light source configured to provide a first excitation signal to tissue of a patient, the first excitation signal configured to generate a continuous emission response spectrum from the tissue for at least two selected blood components; and
at least one light detector configured to receive the continuous emission response spectrum and detect a first emission response at a first emission wavelength and a second emission response at a second emission wavelength; and

one or more processors configured to:
calculate a ratiometric value based on a first emission response amplitude at the first emission wavelength and a second emission response amplitude at the second emission wavelength, wherein the first emission wavelength is selected to correspond with an isosbestic maximum associated with the at least two selected blood components of the continuous emission response spectrum and the second emission wavelength is selected to correspond with an isosbestic minimum associated with the at least two selected blood components of the continuous emission response spectrum, and the ratiometric value varies based on hematocrit level of the patient;
compare the calculated ratiometric value to a baseline ratiometric value;
determine a hematocrit level based on the comparison of the calculated ratiometric value to the baseline ratiometric value; and
generate an alert of a condition of the patient based on the comparison.

2. The system of claim 1 , wherein the one or more processors are configured to:
output the hematocrit level to a computing device.

3. The system of claim 1 , wherein the baseline ratiometric value corresponds to a known baseline hematocrit level of the patient.

4. The system of claim 1 , wherein the at least two selected blood components comprise oxygenated hemoglobin (oxy-Hb) and deoxygenated hemoglobin (deoxy-Hb).

5. The system of claim 1 , wherein the medical device comprises the one or more processors.

6. The system of claim 1 , further comprising a computing device configured to receive data from the medical device, wherein the computing device comprises the one or more processors.

7. The system of claim 1 , wherein the medical device is an insertable monitoring device configured for subcutaneous insertion in the patient, wherein the medical device comprises a plurality of electrodes.

8. The system of claim 1 , wherein the condition of the patient is anemia.

9. The system of claim 1 , wherein the condition of the patient is heart failure.

10. An insertable monitoring device configured for subcutaneous insertion in a patient, the insertable monitoring device comprising:
communication circuitry configured to wireless communicate with an external computing device;
a plurality of electrodes;
at least one light source configured to provide a first excitation signal to tissue of a patient, the first excitation signal configured to generate a continuous emission response spectrum from the tissue for at least two selected blood components;
at least one light detector configured to receive the continuous emission response spectrum and detect a first emission response at a first emission wavelength and a second emission response at a second emission wavelength; and
one or more processors configured to:
calculate a ratiometric value based on a first emission response amplitude at the first emission wavelength and a second emission response amplitude at the second emission wavelength, wherein the first emission wavelength is selected to correspond with an isosbestic maximum associated with the at least two selected blood components of the continuous emission response spectrum and the second emission wavelength is selected to correspond with an isosbestic minimum associated with the at least two selected blood components of the continuous emission response spectrum, and the ratiometric value varies based on hematocrit level of the patient;
compare the calculated ratiometric value to a baseline ratiometric value;
determine a hematocrit level based on the comparison of the calculated ratiometric value to the baseline ratiometric value; and
control the communication circuitry to transmit an alert of a condition of the patient to the external computing device based on the comparison.

11. The insertable monitoring device of claim 10 , wherein the one or more processors are configured to:
output the hematocrit level to the external computing device.

12. The insertable monitoring device of claim 10 , wherein the baseline ratiometric value corresponds to a known baseline hematocrit level of the patient.

13. The insertable monitoring device of claim 10 , wherein the at least two selected blood components comprise oxygenated hemoglobin (oxy-Hb) and deoxygenated hemoglobin (deoxy-Hb).

14. The insertable monitoring device of claim 10 , wherein the condition of the patient is anemia.

15. The insertable monitoring device of claim 10 , wherein the condition of the patient is heart failure.

16. A method comprising:
providing, by at least one light source of a medical device, a first excitation signal to tissue of a patient, the first excitation signal configured to generate a continuous emission response spectrum from the tissue for at least two selected blood components;
receiving, by at least one light detector of the medical device, the continuous emission response spectrum and detecting a first emission response at a first emission wavelength and a second emission response at a second emission wavelength;
calculating, by one or more processors, a ratiometric value based on a first emission response amplitude at the first emission wavelength and a second emission response amplitude at the second emission wavelength, wherein the first emission wavelength is selected to correspond with an isosbestic maximum associated with the at least two selected blood components of the continuous emission response spectrum and the second emission wavelength is selected to correspond with an isosbestic minimum associated with the at least two selected blood components of the continuous emission response spectrum, and the ratiometric value varies based on hematocrit level of the patient;
comparing, by the one or more processors, the calculated ratiometric value to a baseline ratiometric value;
determining, by the one or more processors, a hematocrit level based on the comparison of the calculated ratiometric value to the baseline ratiometric value; and
generating, by the one or more processors, an alert of a condition of the patient based on the comparison.

17. The method of claim 16 , further comprising outputting, by the one or more processors, the hematocrit level to a computing device.

18. The method of claim 16 , wherein the baseline ratiometric value corresponds to a known baseline hematocrit level of the patient.

Assignees

• Medtronic Monitoring Inc

Inventors

• Katra Rodolphe

Classifications

• A61B5/14535 Primary

  for measuring haematocrit · CPC title

• A61B5/6826

  Finger · CPC title

• A61B5/02028

  Determining haemodynamic parameters not otherwise provided for, e.g. cardiac contractility or left ventricular ejection fraction · CPC title

• A61B2562/0233

  Special features of optical sensors or probes classified in A61B5/00 · CPC title

• A61B5/0082

  adapted for particular medical purposes · CPC title