Patent ID: 11925441
Assignee: OURA HEALTH OY
Field: Medical technology (Instruments)
Classification: CPC A | IPC A

Claim 12:
13. A method for measuring blood pressure comprising:
acquiring photoplethysmogram (PPG) data from a user using a wearable device, the PPG data collected during a time interval including a heartbeat of the user, the PPG data comprising at least a first PPG waveform acquired using first light associated with a first wavelength and a second PPG waveform acquired using second light associated with a second wavelength;
determining a second derivative of the first PPG waveform associated with the first wavelength, and an additional second derivative of the second PPG waveform associated with the second wavelength;
determine a peak of the second derivative corresponding to a systolic peak of the first PPG waveform, and a peak of the additional second derivative corresponding to a systolic peak of the second PPG waveform;
determining a first set of morphological features associated with the first PPG waveform based at least in part on the systolic peak and a diastolic peak corresponding to the heartbeat within the first PPG waveform, wherein the first set of morphological features comprise the first peak of the second derivative of the first PPG waveform;
determining a second set of morphological features associated with the second PPG waveform based at least in part on the systolic peak and a diastolic peak corresponding to the heartbeat within the second PPG waveform, wherein the second set of morphological features comprise the second peak of the additional second derivative of the second PPG waveform; and
determining a blood pressure metric for the user based at least in part on a comparison of the first set of morphological features and the second set of morphological features and based at least in part on a delay between the peak of the second derivative of the first PPG waveform and the peak of the additional second derivative of the second PPG waveform.