ARTERIAL DISTENSION AND BLOOD PRESSURE MEASUREMENTS BY USING ULTRASOUND

Ultrasound (US) is one of the newest methods used to measure vital parameters, such as blood pressure (BP). Continuous, non-invasive, and accurate measurements are very attractive for the patient and clinicians. US sensors developed up to now extract noninvasively BP by using algorithms based on a constant brachial stiffness, leading to wrong values. Due to the nonlinear viscoelasticity properties of the radial, brachial and carotid arteries, high variations on the strain and stiffness of this during one cardiac cycle are expected. Site-specific and patient-specific models are required to extract BP from different arteries. For this purpose, an customed 5 MHz piezo transducer, operating in A-Mode made of lead zirconate titanate, has been used. Thanks to a high accurate and ultra-broadband (1 KHz–30 MHz) modeling of the piezo based on a multiresonant Butterworth-Van-Dyke model, a high-speed and high-gain peak detector could be developed. This US system allows for continuous and non-invasive measurement of the diameter distension and BP of peripheral arteries (i.e. radial and carotid), which determine the biological age of the vascular tree and deliver a more relevant predictive maker of cardiovascular events and changes than brachial BP.