Abstract
Purpose
Electrical Impedance Tomography (EIT) holds promise as a non-invasive method for measuring lung airflow, particularly in patients diagnosed with Chronic Obstructive Pulmonary Disease (COPD). Nonetheless, there are challenges regarding the clinical relevance of EIT. The main purpose of the present research was to identify the primary frequency components of impedance changes recorded by EIT and correlate them with pulmonary function parameters.
Methods
20 COPD patients were analyzed. Each volunteer was connected to a pneumotachometer and an EIT device. They performed three respiratory exercises, and pulmonary function parameters for each volunteer were acquired. The three impedance signals were convolved to simulate the behavior of the thorax as a black box with a single output signal. The convolved impedance signal was analyzed using FFT spectra. Subsequently, it was divided into seven frequency ranges, estimating the area under the curve and quartiles at 25%, 50%, and 75%. Each segment of the FFT spectrum was correlated with each pulmonary function test parameter.
Results
A significant correlation of over 60% between pulmonary function test parameters and the determinations from the FFT spectrum within seven distinct frequency ranges was observed. However, the determination coefficient (R2) ranged from approximately 10–66% due to data points that did not fit well, particularly in patients with severe pulmonary dysfunction.
Conclusion
To address the dispersion of data and enhance the correlation between determinations, it is imperative to adjust impedance determinations using anthropometric parameters or employ a mathematical equation that facilitates the characterization of limitations in lung airflow.
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Data Availability
Data will be made available upon reasonable request.
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Funding
The authors thank IDEA-Guanajuato and Direccion de Apoyo a la Investigación y al Posgrado (DAIP) for their financial support (codes CIIC 2023, 213/2023 and IDEAGTO/CONV/036/2022, respectively).
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FMVL: Data acquisition, data analysis and interpretation, the first draft of the manuscript. MIDC: Data analysis and interpretation, review of the manuscript. JPRC: Study design, data analysis and interpretation, review of the manuscript. SK: Study design, data acquisition, data analysis and interpretation, review of the manuscript, funding acquisition. JMBO: Study design, data acquisition, data analysis and interpretation, review of the manuscript, funding acquisition. All authors approved the version to be published and agree to be accountable for all aspects of the work in ensuring that questions related to the accuracy or integrity of any part of the work are appropriately investigated and resolved.
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Vargas-Luna, F.M., Delgadillo-Cano, M.I., Riu-Costa, J.P. et al. Assessing Pulmonary Function Parameters Non-invasively by Electrical Bioimpedance Tomography. J. Med. Biol. Eng. 44, 67–78 (2024). https://doi.org/10.1007/s40846-023-00842-8
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DOI: https://doi.org/10.1007/s40846-023-00842-8