Implantable multi sensor system for in vivo monitoring of cardiovascular parameters

A novel implantable sensor for continuous long-term monitoring of various cardiovascular parameters is presented. An optical arterial blood oxygen saturation sensor and a piezoelectric blood pressure sensor have been developed using a silicone-based fabrication technology. An elastic silicone stripe houses the sensors and is wrapped around an arterial blood vessel. Due to this choice of a soft material, no necking of the vessel or influence on the blood flow occur even at large dilatations of 10%. The pulse oximetric sensor is able to measure oxygen saturations in the physiologically relevant range of 65% - 100% (psO₂) with a precision of plusmn1%. The piezoelectric blood pressure sensor uses a 70 mum cellular polypropylene (PP) layer which responds to the dilatation of the blood vessel with a sensitivity of 0.75 mV/mmHg.