PROJECT TITLE :

Continuous Cuffless Blood Pressure Estimation Using Pulse Transit Time and Photoplethysmogram Intensity Ratio

ABSTRACT:

Pulse transit time (PTT) has attracted much interest for cuffless blood pressure (BP) measurement. However, its limited accuracy is one in every of the most problems preventing its widespread acceptance. Arterial BP oscillates mainly at high frequency (HF) because of respiratory activity, and at low frequency (LF) because of vasomotor tone. Previous studies advised that PTT can track BP variation in HF range, however was inadequate to follow the LF variation, that is probably the main reason for its unsatisfactory accuracy. This paper presents a new indicator, the photoplethysmogram intensity ratio (PIR), that can be affected by changes in the arterial diameter, and, so, trace the LF variation of BP. Spectral analysis of BP, PTT, PIR, and respiratory signal confirmed that PTT was related to BP in HF at the respiratory frequency, while PIR was associated with BP in LF range. We, therefore, develop a novel BP estimation algorithm by using each PTT and PIR. The proposed algorithm was validated on 27 healthy subjects with continuous Finapres BP as reference. The results showed that the mean ± normal deviation (SD) for the estimated systolic, diastolic, and mean BP with the proposed methodology against reference were , , mmHg, and mean absolute distinction (MAD) were four.09, 3.18, 3.18 mmHg, respectively. Furthermore, the proposed method outperformed the 2 most cited PTT algorithms for concerning a pair of mmHg in SD and MAD. These results demonstrated that the proposed BP model using PIR and PTT will estimate continuous BP with improved accuracy.