Non-invasive wearable blood pressure monitoring system

• US 10,327,649 B1
• Filed: 09/01/2016
• Issued: 06/25/2019
• Est. Priority Date: 03/31/2014
• Status: Active Grant

• Current Assignee: Kehaai Incorporated
• Original Assignee: Sensogram Technologies, Inc.
• Inventors: Mouradian, Vahram, Poghosyan, Armen
• Primary Examiner(s): Cattungal, Sanjay
• Application Number:
  US15/254,880
• Time in Patent Office: 1,027 Days
• Field of Search: 600473-480
• CPC Class Codes: A61B 5/02108 from analysis of pulse wave characteristics
• CPC Class Codes: A61B 5/02416 using photoplethysmograph signals, e.g. generated by infrared radiation A61B5/14552 takes precedence
• CPC Class Codes: A61B 5/026 Measuring blood flow A61B3/1233, A61B3/1241 take precedence
• CPC Class Codes: A61B 5/0295 using plethysmography, i.e. measuring the variations in the volume of a body part as modified by the circulation of blood therethrough, e.g. impedance plethysmography
• CPC Class Codes: A61B 5/6801 specially adapted to be attached to or worn on the body surface
• CPC Class Codes: A61B 5/7221 Determining signal validity, reliability or quality A61B5/7207 and A61B5/7217 take precedence

Abstract

Presented are embodiments of an apparatus and methodology for non-invasive, continuous or semi-continuous monitoring of human blood pressure by photoplethysmography (PPG) based sensor system.

Claims

1. A method of continuously monitoring blood pressure, the method comprising:

(a) retrieving previously stored values for inductance (L) and compliance of the cardiovascular system (C);

(b) receiving a photoplethysmographic (PPG) signal for each pulse or for a given time period;

(c) filtering the received PPG signal to produce a clean PPG signal;

(d) determining the heart rate;

(e) determining the peripheral resistance using the heart rate and a profile-based lookup table;

(f) calculating the blood pressure using the clean PPG signal, the peripheral resistance, L and C; and

(g) determining the systolic and diastolic blood pressure.

2. The method of claim 1, further comprising performing a calibration sub-process to determine L and C for each individual user.

3. The method of claim 1, further comprising repeating steps (a) through (g) for each predetermined time period.

4. The method of claim 1, further comprising repeating steps (a) through (g) for each pulse of a user.

5. The method of claim 1, further comprising storing the systolic and diastolic blood pressure in a memory.

6. A system for continuously monitoring blood pressure, the system comprising:

a light source;

an optical sensor positioned to receive reflected light from the light source;

a signal processing unit adapted to receive an electrical signal from the optical sensor and configured to output a clean digital signal;

a microprocessor in communication with the light source, the signal processing unit, a memory and a computer/wireless interface, the microprocessor having instructions for;

(a) retrieving previously stored values for inductance (L) and compliance of the cardiovascular system (C);

(b) receiving a photoplethysmographic (PPG) signal for each pulse or for a given time period;

(c) filtering the received PPG signal to produce a clean PPG signal;

(d) determining the heart rate;

(e) determining the peripheral resistance from thea selected profile-based lookup table using the heart rate;

(f) calculating the blood pressure using the clean PPG signal, the peripheral resistance, L and C; and

(g) determining the systolic and diastolic blood pressure.

7. The system of claim 6, further comprising performing a calibration sub-process to determine L and C for each individual user.

8. The system of claim 6, further comprising repeating instructions (a) through (g) for each predetermined time period.

9. The system of claim 6, further comprising repeating instructions (a) through (g) for each pulse of a user.