Calibration of pulse-transit-time to blood pressure model using multiple physiological sensors and various methods for blood pressure variation
AssigneeFitbit, Inc.
InventorsAlexandros A. Pantelopoulos, Thomas Samuel Elliot, Logan Niehaus
Life of this patent
Estimating the term…
Abstract
Disclosed are devices and methods for estimating blood pressure, which implement a pulse-transit-time-based blood pressure model that can be calibrated. Some implementations provide reliable and user friendly means for calibrating the blood pressure model using blood pressure perturbation methods and multiple sensors.
Claims11
A method implemented using a system comprising a calibration blood pressure measuring device, one or more sensors configured to measure pulse transit time and one or more inertial sensors to measure whether a person is stationary, a memory, and one or more processors, the method comprising:
- providing instructions to instruct the person to initiate a calibration of the system by performing a Valsalva maneuver for a period of time, wherein initiating the calibration of the system by performing the Valsalva maneuver for the period of time includes:
- (a) obtaining, by the one or more sensors, photoplethysmography (PPG) data from the person during the period of time when the person is performing the Valsalva maneuver, and
- (b) in response to determining, by the one or more processors, that the person is stationary based on inertial data obtained from the one or more inertial sensors and in response to determining, by the one or more processors, that an amplitude of the PPG data obtained from the person during the period of time when the person is performing the Valsalva maneuver has decreased in the period of time by more than a threshold value, automatically:
- taking at least one measurement of a blood pressure of the person with the calibration blood pressure device when the person is performing the Valsalva maneuver, wherein the calibration blood pressure measuring device is selected from a group consisting of an oscillometric blood pressure device, a sphygmomanometer, an arterial tonometry device, a volume clamp device, and any combinations thereof, wherein the calibration blood pressure measuring device does not comprise a mouthpiece pressure transducer, and
- obtaining proximal pulse wave PPG data and distal pulse wave PPG data from the one or more sensors when the person is performing the Valsalva maneuver;
- (c) determining, by using the one or more processors, at least one pulse transit time based on a temporal difference between a first peak of the proximal pulse wave PPG data and a second peak of the distal pulse wave PPG data obtained when the person is performing the Valsalva maneuver;
- (d) obtaining, by using the one or more processors, at least one calibration data point corresponding to the at least one measurement of the blood pressure and the at least one pulse transit time;
- (e) fitting, by using the one or more processors, a model to two or more data points comprising the at least one calibration data point, wherein the model relates the blood pressure of the person to the pulse transit time of the person;
- (f) calibrating, by using the one or more processors, the system using the fitted model;
- and
- (g) using the calibrated system to determine a blood pressure based on a pulse transit time measured using the one or more sensors.
Dependencies are inferred from the claim text.