Non-invasive monitoring of central blood pressure by electrical impedance tomography: first experimental evidence

Abstract

There is a strong clinical demand for devices allowing continuous non-invasive monitoring of central Blood Pressure (BP). In the state of the art a new family of techniques providing BP surrogates based on the measurement of the so-called Pulse Wave Velocity (PWV) has been proposed, eliminating the need for inflation cuffs. PWV is defined as the velocity at which pressure pulses propagate along the arterial wall. However, no technique to assess PWV within central arteries in a fully unsupervised manner has been proposed so far. In this pilot study we provide first experimental evidence that Electrical Impedance Tomography (EIT) is capable of measuring pressure pulses directly within the descending aorta. To obtain a wide range of BP values we administrated noradrenalin and nitroglycerine to an anesthetized pig under mechanical ventilation. An arterial line was inserted into the ascending aorta for measuring reference BP. EIT images were generated from 32 impedance electrodes placed around the chest at the level of the axilla. Regions of Interest (ROI) such as the descending aorta and the lungs were automatically identified by a novel time-based processing algorithm as the respective EIT pixels representing these structures. The correct positions of these ROIs were confirmed by bolus injections of highly conductive concentrated saline into the right heart and into the ascending aorta. Central blood pressure by EIT

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Waveform Sensors: The Next Challenge in Biomimetic Electroreception

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A feasibility study of magnetic resonance electrical impedance tomography for prostate cancer detection

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