MP Research Catalog - Biopac

16Electrical BioimpedanceCardiac OutputCardiac Output Q13To determine Cardiac Output noninvasively, employelectrical bioimpedance measurement techniques withthe EBI100C. With pairs of EL500 electrodes attachedto the neck and torso, the EBI100C can isolate the base[Z(t)] and delta impedance (dZ/dt) values, which vary asthe heart pumps blood. In real time, dZ/dt magnitudeand heart rate can be determined on a cycle-by-cyclebasis. Simultaneously, the DA100C and the TSD108Record the parameters associated with cardiac outputmeasurements, thoracic impedance changes as a functionof respiration, or any kind of biological impedancemonitoring. The EBI100C incorporates a precision highfrequency current source, which injects a very small(100µA) current through the measurement tissue volumedefined by the placement of a set of current sourceelectrodes. A separate set of monitoring electrodes thenmeasures the voltage developed across the tissue volume.Because the current is constant, the voltage measuredis proportional to the characteristics of the biologicalimpedance of the tissue volume.Features• Cardiac Output via Impedance Cardiography• Systemic Vascular Resistance• Left Cardiac Work• Peripheral Blood Flow• Tissue Magnitude & Phase Modeling• Pulse Rate Measurement• Tissue Resistance & Reactance Measurement• Body Composition Analysis• Respiration Monitoring• Z(t)• dZ/dt• dZ/dt maximum• BPM• LVET• Stroke volume• Cardiac outputcan identify aortic valve opening and closing times. Usethe Equation Generator to combine data from these varioussources to compute Stroke Volume and Cardiac Outputon-line. One possible equation for determining StrokeVolume is (from Nyboer, 1970):where∆V = ρ • (L 2 /Z O2) • T • (dZ min /dt)∆V = Stroke Volumeρ = Resistivity of BloodT = LVETL = Length Between Recording ElectrodesdZ min /dt = Magnitude of Largest ImpedanceChange During Systole