Design and Development of textile based fibre optics sensor for biomedical applications
Tittle : Cuff-Less Continuous Blood Pressure Monitoring Using Pulse Transit Time Techniques.
Abstract : Continuous blood pressure measurement could be a very useful approach to monitor hypertension, or to prevent falling accidents related to orthostatic hypotension (low pressure). Currently, blood pressure is monitored continuously using a noninvasive blood pressure monitor based on auscultatory method. This method widely used for monitoring blood pressure due to the accuracy of the measurement. However, the inflatable cuff may give pain and discomfort to a patient for long period used. Therefore, this project focuses on development of a cuff-less blood pressure monitoring system based on the pulse transit time (PTT) technique. In this project, PTT is defined as the delay time between the R peak of the Electrocardiogram (ECG) signal and the peak wave of the Photoplethysmography (PPG) signal. The ECG signal is acquired on the chest using a 3 lead electrode and a reflection mode optical sensor used to monitor the PPG signal on the right finger. These data were synchronised using a National Instrument data acquisition card and Matlab software is used for further analysis. A commercial blood pressure monitor was worn on the left upper arm for calibration process. The experiments were conducted by elevating the hand at different position to investigate variability of PTT under the effects of hydrostatic pressure. Next the variability of PTT due to blood pressure changes during valsalva manoeuvre was investigated. The results shows that the PTT steadily decreases as the hand elevated above heart level. In valsalva manoeuvre experiments, the PTT is inversely proportional to blood pressure measurements. These preliminary results indicate that PTT has potential to be a reliable technique for cuff-less blood pressure measurement.