Non-invasive wearable blood pressure monitoring system
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.
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.