Sensor for vascular compliance and blood pressure

A method for continuous sensing of blood pressure and vascular compliance without affecting the state of the patient has been devised. The scheme is based on sensing vascular distention by a capacitive method utilizing the fact that the dielectric constant of blood is different from the dielectric constant of the surrounding tissue. The vascular stiffness is determined by measuring the pulse propagation velocity through an artery. Knowing the distention and the stiffness both vascular compliance and blood pressure can be calculated. A special signal processing scheme is devised in order to eliminate the effects of movements that are not synchronous with the heart beat. It is based conditional averaging and matched filtering. A wireless implementation has been verified.