Cuffless Blood Pressure Sensing Using Pulse Wave Morphology

The patent replaces the mechanical inflatable cuff system with an optical sensing system. Specifically, it uses photoplethysmography (PPG) to capture pulse wave signals from the skin, combined with machine learning algorithms to estimate blood pressure. This substitution eliminates the need for mechanical inflation and deflation mechanisms, making the device wearable and comfortable while maintaining measurement capability through optical detection and computational analysis.

The patent transforms the measurement approach by changing from direct mechanical pressure detection to optical parameter detection. It measures optical absorption and reflection properties of blood vessels during different phases of the cardiac cycle, then uses these optical parameters to infer blood pressure values through trained models. This parameter transformation enables non-invasive, continuous monitoring without mechanical intervention.

The patent eliminates complex mechanical components (inflatable cuffs, pressure sensors, pumps, valves) by substituting them with simple optical sensors and computational algorithms. The sensing assembly includes only light sources and photodetectors, dramatically reducing mechanical complexity while maintaining measurement reliability through sophisticated signal processing and machine learning models that compensate for physiological variations.

The patent uses optical copying of blood volume changes instead of direct mechanical pressure measurement. The PPG sensor captures optical signatures of blood flow dynamics, creating an indirect copy of hemodynamic information that can be analyzed to infer blood pressure. This copying approach simplifies the physical measurement mechanism while preserving the essential physiological information needed for reliable blood pressure estimation.

The patent replaces the cumbersome mechanical cuff inflation process with a simple optical sensing operation. Users only need to place their finger or wrist on the sensor, and the device automatically captures pulse wave signals and computes blood pressure. This eliminates the discomfort and time associated with cuff inflation, enabling frequent on-demand measurements without sacrificing user convenience.

The device performs automatic blood pressure estimation without requiring user intervention beyond initial contact. The system self-calibrates by capturing baseline pulse wave characteristics, automatically processes the optical signals through machine learning models, and provides results without manual calibration or adjustment. This self-service capability enables effortless repeated measurements throughout the day.