Blood Pressure Estimation via Wearable Pulse Timing Synchronization
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Solution Overview
Problem
Traditional blood pressure measurement devices are bulky and uncomfortable for continuous wear, and existing wearable devices face signal processing limitations and timing synchronization issues when estimating blood pressure using pulse transmit times (PTTs), leading to inaccurate measurements.
Innovation Solution
The use of wearable devices, such as rings and smartphones with cameras, to synchronize internal clocks and measure pulse transit times (PTTs) by strobing LEDs or detecting heartbeats, allowing for more accurate blood pressure estimation through relative timing of pulses.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If traditional blood pressure measurement devices are used, then measurement accuracy is maintained, but device portability and comfort for continuous wear deteriorate
Solution Approach 1:
The patent replaces traditional mechanical blood pressure measurement systems with optical detection methods. Wearable devices use photodetectors to detect pulse waves through photoplethysmography (PPG), eliminating the need for bulky mechanical cuffs while maintaining measurement capability through optical signals that penetrate tissue to detect blood volume changes.
Solution Approach 2:
The wearable device integrates multiple functions including pulse wave detection, timing synchronization, and blood pressure estimation in a single compact unit. The device can simultaneously perform heart rate monitoring, pulse transit time measurement, and serve as a timing reference for multiple devices, reducing the need for separate specialized equipment.
2Duration of action of moving object
If pulse transit time (PTT) method is used for blood pressure estimation, then continuous monitoring capability is improved, but timing synchronization accuracy between devices deteriorates
Solution Approach 1:
The patent introduces a dedicated timing signal and synchronization protocol as an intermediary between multiple wearable devices. A reference device generates precise timing signals that are transmitted to other devices, creating a common time base that coordinates pulse wave detection across multiple sensors without requiring direct device-to-device synchronization.
Solution Approach 2:
The system implements feedback mechanisms where detected pulse waves are used to adjust and refine timing synchronization. The devices continuously monitor the timing of detected pulses and adjust their internal clocks to maintain synchronization, using the physiological signal itself as a feedback reference for timing calibration.
3Adaptability or versatility
If multiple wearable devices are used for pulse timing measurement, then measurement coverage is improved, but device complexity and synchronization difficulty increase
Solution Approach 1:
The patent divides the blood pressure measurement function across multiple segmented wearable devices placed at different body locations. Each device independently detects pulse waves at its specific location and transmits timing data to a central processing system, allowing distributed measurement coverage while simplifying individual device design and reducing synchronization complexity through modular architecture.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
Enables more frequent and accurate blood pressure measurements by improving timing synchronization between devices, providing a comfortable and continuous monitoring solution.
Implementation Method 1
transmitting light associated with one or more wavelengths into the tissue of the user at different tissue penetration depths
Implementation Method 2
a photodetector to receive the transmitted light and acquire physiological data in response to the transmitted light
Data Source
AI summary
Methods, systems, and devices for synchronizing multiple devices for determining physiological metrics are described. A method may include flashing light-emitting diodes (LEDs) of a wearable device, and capturing images of the flashing LEDs using an imaging device. A synchronization procedure may be performed to identify a delay between internal clocks at the wearable device and the imaging device based on capturing the images. Subsequently, the wearable device and the imaging device may collect physiological data at different physiological locations on the user's body, where the physiological data includes separate pulse observation times of a heartbeat of the user at the different physiological locations. Subsequently a pulse transmit time (PTT) associated with the heartbeat may be determined based on the delay and a comparison between the pulse observation times, and a blood pressure metric for the user is determined based on the PTT.