Methods and systems for extracting venous pulsation and respiratory information from photoplethysmographs

Abstract

A system and method for separating a venous component and an arterial component from a red signal and an infrared signal of a PPG sensor is provided. The method uses the second order statistics of venous and arterial signals to separate the venous and arterial signals. After reliable separation of the venous and the arterial component signals, the component signals can be used for different purposes. In a preferred embodiment, the respiratory signal, pattern, and rate are extracted from the separated venous component and a reliable 'ratio of ratios' is extracted for SpOusing only the arterial component of the PPG signals. The disclosed embodiments enable real-time continuous monitoring of respiration pattern/rate and site-independent arterial oxygen saturation.