A Novel Indicator for Cuff-Less Blood Pressure Estimation Based on Photoplethysmography

Cuff-less blood pressure (BP) measurement provides an efficient way to estimate blood pressure and thus prevent cardiovascular disease caused by hypertension. Pulse transit time (PTT) based BP estimation model has attracted much interests but with limited application. The measurement of PTT needs two photoplethysmographic (PPG) sensors or one electrocardiogram (ECG) sensor and one PPG sensor and thus restricted its widespread acceptance. In this study, a novel indicator, Photoplethysmography Acceleration Ratio (PAR), is extracted from the second-order derivative of PPG signal, which is validated as a significant parameter for estimating BP. 120 subjects, aged from 18 to 84, participated in this experiment. The results show that the correlation coefficient between PAR and systolic, diastolic and mean BP are 0.701, 0.331 and 0.629 respectively. Furthermore, the performance of accuracy and precision is good through correlation analysis. Therefore, the proposed PAR is demonstrated to be useful for SB measurement with only one sensor.