EDUCATIONAL SOFTWARE FOR CARDIAC FLOW MEASUREMENTS AND HEMODYNAMIC ANALYSIS

Impedance plethysmography is a method for determining changes in body tissue volumes, based on the measurement of electric impedance at the body surface. Because it is a non-invasive and cost-effective method to measure and analyze hemodynamics, it would bring to students important information for the continuous care of patients with hemodynamic disorders. This study aimed at acquiring non-invasively and at analyzing plethysmografic waves by measuring the electrical impedance. For measurements we use a device that was designed as an injection module with a microcontroller, a programmable waveform generator, and a voltage controlled current source which generates a sinusoidal pulse with adjustable frequency (10-200 kHz) and adjustable intensity. In output, the device delivers an analogical signal representing the variation of the impedance of the explored section. The acquisition of the bioimpedance signal on PC was made easier by the use of a National Instrument data acquisition device, the NI USB 6009. The bioimpedance signal processing, the user interface and the display were managed by MATLAB. Also the data analysis program was developed in this software. It offers the opportunity of creating user interfaces by the Graphical User Interface Instrument GUIDE. The purpose of implementing the graphical user interface (GUI) in this project, was of obtaining programs more easy to use by means of certain visual elements associated with control actions and display actions as slides, buttons, menus, diagrams. A graphical user interface offers to the student a manner of interoperating very efficiently with all the elements coordinated by this environment. Also the software have the possibility to calculate some cardiac parameters like the perfusion coefficient, vascular elasticity, analysis of the rate of pulsatory wave, performing of hemodynamic studies during physical efforts, drug testing.