A novel cuffless technique for non-invasive blood pressure measurement under post-exercise conditions

Cardiovascular diseases (CVD) are the leading cause of death. It is also one of the major factors resulting sudden deaths in exercises. Blood pressure (BP) is one of the vital diagnostic parameters to reflect the functionality of cardiovascular system and evaluate the conditions of CVD. However, current BP measuring devices usually require the occlusion of cuff that causes inconvenience to users during measurement. They are neither suitable nor practical for long-term monitoring. Pulse transit time (PTT), the duration for a pressure pulse wave to travel from one arterial site to another, has been proposed as a potential parameter for cuffless BP measurement in recent decades. Because of its cuffless and non-invasive measuring features, the aim of the present study is to develop a novel PTT-based BP estimation for cuffless and non-invasive monitoring of BP under resting and exercise conditions.;The accuracy of proposed method for continuous BP monitoring has been evaluated on seventeen subjects during cycling. Brachial BP was measured by FinapresRTM (Fin. BP) and a trained nurse (Nur. BP). In approximate 22000 beats, the differences between predictions and Fin. BP were 1.3+/-13.0 mmHg for SBP and -1.5+/-6.1 mmHg for DBP respectively. The intermittent BP measurements using the proposed method were compared to the readings from FinapresRTM and nurse separately. The differences between proposed method and Nur. BP were 0.9+/-9.9 mmHg for SBP and -1.2+/-5.2 mmHg for DBP respectively. The differences between proposed method and Fin. BP were -0.1+/-12.6 mmHg for SBP and -1.4+/-5.9 mmHg for DBP respectively. The predictions using the proposed method were more consistent with the nurse readings. Furthermore, thorax impedance signal was proposed for cuffless BP estimation and it was examined on twenty-two subjects. The results illustrated that proposed parameters, measured from Q wave of electrocardiogram to the peaks of thorax impedance signal and its derivative, were highly correlated with BP. They were potential parameters to provide non-invasive and cuffless BP estimation.;To conclude, the accuracy of proposed method was comparable to the cuff-based approaches under resting and exercise conditions. This work is potential to solve the problems due to prevalence of CVD and rising aging population. (Abstract shortened by UMI.)...