A polyvinylidene fluoride (PVDF) piezoelectric biomedical transducer for intravascular monitoring of blood pressure, and arterial blood flow rate

A number of patients undergoing anesthesia for various surgical procedures require a more precise and sophisticated level of cardiovascular monitoring than can be obtained from standard, noninvasive techniques. Placement of a microcatheter, usually in the radial artery, and connection of the catheter to electronic equipment allow for continuous monitoring of a patient's blood pressure. Patients having cardiac, vascular, chest, spine and brain surgery are subject to rapid changes in blood pressure[22].

Work has been conducted to develop an in-situ parameter monitoring (pressure, flow rate, viscosity, etc.) transducer that has superior functionality and features surpassing what is currently available in commercial sectors; and integrating intra-artery actuating functions to the monitoring probe, that adds active role of breaking blood clots while performing the functions of monitoring. These functions can be extensively examined through a piezoelectric polymeric sensor[9].

The artificially made piezoelectric polymer Polyvinylidene Fluoride (PVDF) film is an excellent material candidate for the development of such sensor/transducer. The development is conducted by converting a PVDF sheet into a tubular sleeve form to perform the sensing and actuating functions. The sensing is interfaced through the use of a peristaltic pump to simulate a heart signal and electronic circuits such as the conventional charge amplifier and traditional high and low pass filters for signal conditioning. The actuating performance the PVDF is analyzed by creating COMSOL computer simulation to explore the resonant frequencies and to compare with those obtained though a experimental measurement using an impedance phase gain analyzer.

Results show that PVDF is capable of performing as a biomedical transducer for in-situ monitoring of change in blood pressure DeltaP ≈ 30.77 mmHg, and a flow rate ≈ 369.5 mL/S. Additionally simulation and experimental setup also demonstrate a low resonant frequencies range between 12--14 kHz depending on material geometry.