Continuous and noninvasive estimation of arterial blood pressure using a photoplethysmographic approach

Arterial blood pressure is one of the most important physiological parameters for the noninvasive diagnosis and monitoring of cardiovascular diseases. This study examines the relationships between arterial blood pressure and certain features of the photoplethysmographic (PPG) signals obtained from 15 young healthy subjects. Width of 1/2 pulse amplitude, width of 2/3 pulse amplitude, systolic upstroke time and diastolic time of the pulse were selected as features of the PPG signals. The experiment involved three sessions: rest, step-climbing exercise, and recovery from exercise. It was found that the diastolic time has higher correlation with systolic blood pressure (SBP) and diastolic blood pressure (DBP) than other features. The mean differences between the estimated and the measured blood pressure using a standard device are 0.21 mmHg for SBP and 0.02 mmHg for DBP. The corresponding standard deviations are 7.32 mmHg for SBP and 4.39 mmHg for DBP. The preliminary results indicate that it is possible to use the photoplethysmography only for cuffless and continuous estimation of arterial blood pressure.