Implantable Acceleration Plethysmography for Blood Pressure Determination

This paper presents an implantable accelerometer which detects plethysmograms directly at an artery. The sensor provides a new method for continuous blood pressure monitoring. In vivo measurements indicate that the accelerometer is well suited for determining the Pulse Transit Time (PTT) and the Reflected Wave Transit Time (RWTT). Both parameters show a high correlation with the systolic blood pressure. By varying the blood pressure, it was seen that RWTT more closely agrees with theory than PTT. Through several blood pressure sweeps the RWTT, as detected by the accelerometer, coincided very well with the systolic blood pressure, with a correlation coefficient of 0.96 and mean deviation of 4.3% for 1800 pulses.