Method and apparatus for measuring blood pressure

A non-transitory computer program product comprising a computer readable medium having computer readable code embodied therein, the computer readable code being configured such that, on execution by a suitable computer or processor, the computer or processor is caused to perform steps comprising:

• applying pressure to a first part of a body of the user using a volume-clamp blood pressure (BP) monitoring device comprising a first pressure device;
• obtaining a first PPG signal, via a first photoplethysmogram (PPG) sensor, from the first part of the body of the user;
• analyzing the first PPG signal;
• controlling the pressure of the first pressure device to maintain the first PPG signal at a constant level over time;
• applying pressure to a second part of the body of the user using a second pressure sensor;
• measuring a physiological characteristic of the user in the second part of the body of the user via a second PPG sensor that is separate from the first PPG sensor, wherein the second part of the body is separate from the first part of the body;
• alternately measuring the blood pressure of the user using the first pressure device and the first PPG sensor, and the second pressure device and the second PPG sensor;
• analyzing the PPG signal from the second PPG sensor to determine a measure of the blood perfusion in the second part of the body of the user when the first pressure device and first PPG sensor are being used to measure the BP of the user in the first part of the body of the user;
• analyzing the PPG signal from the first PPG sensor in to determine a measure of the blood perfusion in the first part of the body of the user when the second pressure device and second PPG sensor are being used to measure the BP of the user in the second part of the body of the user;
• and
• determining whether to perform a recalibration of the volume-clamp BP monitoring device based on at least one of:
• changes in the measure of blood perfusion at the first part of the body and changes in the measure of blood perfusion at the second part of the body.

A method of measuring blood pressure (BP) of a user, the method comprising:

• applying pressure to a first part of a body of the user using a volume-clamp blood pressure (BP) monitoring device comprising a first pressure device;
• obtaining a first PPG signal, via a first photoplethysmogram (PPG) sensor, from the first part of the body of the user;
• analyzing the first PPG signal;
• controlling the pressure of the first pressure device to maintain the first PPG signal at a constant level over time;
• applying pressure to a second part of the body of the user using a second pressure sensor;
• measuring a physiological characteristic of the user in the second part of the body of the user via a second PPG sensor that is separate from the first PPG sensor, wherein the second part of the body is separate from the first part of the body;
• alternately measuring the blood pressure of the user using the first pressure device and the first PPG sensor, and the second pressure device and the second PPG sensor;
• analyzing the PPG signal from the second PPG sensor to determine a measure of the blood perfusion in the second part of the body of the user when the first pressure device and first PPG sensor are being used to measure the BP of the user in the first part of the body of the user;
• analyzing the PPG signal from the first PPG sensor in to determine a measure of the blood perfusion in the first part of the body of the user when the second pressure device and second PPG sensor are being used to measure the BP of the user in the second part of the body of the user;
• and
• determining whether to perform a recalibration of the volume-clamp BP monitoring device based on at least one of:
• changes in the measure of blood perfusion at the first part of the body and changes in the measure of blood perfusion at the second part of the body.