Noninvasive Cuffless Estimation of Blood Pressure using Photoplethysmography without Electrocardiograph Measurement

The paper presents a novel approach of measuring blood pressure using Photoplethysmography (PPG). It is a noninvasive, cuffless and painless technique that deploys infrared light to detect small variation in blood volume in the tissues with each cardiac cycle. Few specific features (viz. systolic upstroke time (ST), diastolic time (DT) and the time delay between the systolic and diastolic peak (T1)) of the waveform obtained via this technique were examined and correlated with the arterial blood pressure in 22 subjects of two age groups i) 18-25 years ii) 26-50 years. It was observed that there is a good correlation of blood pressure (both systolic blood pressure (SBP) and diastolic blood pressure (DBP)) with diastolic time and also with the time delay between systolic and diastolic peak.