Experimental evaluation of an intravascular differential pressure flow meter using MEMS pressure sensors

A testbed for differential pressure flow meter was built and tested. The testbed is targeted for intravascular pressure and flow monitoring applications. The testbed consists of a data acquisition system and two MEMS pressure sensors (SM5108) measuring 0.65×0.65×0.65mm. The MEMS pressure sensors were wire bonded to gold plated ceramic pads and placed inside vinyl tubing. The signals from the pressure sensors were amplified using two low-power high performance instrumentation amplifiers. These amplifiers are a part of the data acquisition system which is designed to acquire data from the pressure sensors and communicate with a user in real time. For simplicity our initial evaluation of the testbed was using air flow. Air was pumped across a simulated blockage (a valve) and pressure was built up to intravascular pressure ranges (35 to 230 mmHg (gauge)). The base fractional flow rate (FFR) equation was used to calculate flow, hinting that the SM5108 pressure sensors can become a part of an implantable differential pressure flow meter.