Fraction of reverse impedance change (FRIC): a quantitative electrical impedance tomography measure of intrapulmonary pendelluft.

Objective . Pendelluft is the movement of air between lung regions, and electrical impedance tomography (EIT) has shown an ability to detect and monitor it. Approach. In this note, we propose a functional EIT measure which quantifies the reverse airflow seen in pendelluft: the Fraction of Reverse Impedance Change (FRIC). Main Results . FRIC measures the fraction of reverse flow in each pixel waveform (as an image) or globally (as a single parameter). Significance . Such a measure is designed to be a more specific measure than previous approaches, to enable comparative studies of the pendelluft, and to help clarify the effect of ventilation strategies.
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