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Figure 1 | Critical Care

Figure 1

From: Measurement of ventilation and cardiac related impedance changes with electrical impedance tomography

Figure 1

Filtering of the EIT signal. (a) The original time course of impedance change of a subject during spontaneous breathing with no filtering applied. (b) The Fast Fourier Transform (FFT) power spectrum of this signal showing the frequency characteristics. The peak frequency highlighted is the respiratory rate, band pass filtering for the respiratory rate was set from 2/minute to 2.5 times the respiratory rate - in this case 42/minute. The heart rate filtered data were extracted using a band pass filter above this rate, that is, 42 to 400/minute. (c) The standard deviation image generated when filtering around the respiratory rate. (d) The standard deviation image generated when filtering around the heart rate.

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Critical Care

ISSN: 1364-8535