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Instantaneous Respiratory Estimation from Thoracic Impedance by Empirical Mode Decomposition.

Wang FT, Chan HL, Wang CL, Jian HM, Lin SH - Sensors (Basel) (2015)

Bottom Line: This measurement imposes little pressure on the body and uses the human body as the sensor, thereby reducing the need for adjustments as body position changes and making it suitable for long-term or ambulatory monitoring.Moreover, large motion artifacts disable the EMD to decompose respiratory components.A novel intrinsic respiratory reconstruction index that considers both global and local properties of IMFs is proposed to define respiration-related IMFs for respiration reconstruction and instantaneous respiratory estimation.

View Article: PubMed Central - PubMed

Affiliation: Department of Electrical Engineering, Hwa Hsia University of Technology, 111, Gongzhuan Rd., Zhonghe, New Taipei City 23568, Taiwan. wft.intuitive@seed.net.tw.

ABSTRACT
Impedance plethysmography provides a way to measure respiratory activity by sensing the change of thoracic impedance caused by inspiration and expiration. This measurement imposes little pressure on the body and uses the human body as the sensor, thereby reducing the need for adjustments as body position changes and making it suitable for long-term or ambulatory monitoring. The empirical mode decomposition (EMD) can decompose a signal into several intrinsic mode functions (IMFs) that disclose nonstationary components as well as stationary components and, similarly, capture respiratory episodes from thoracic impedance. However, upper-body movements usually produce motion artifacts that are not easily removed by digital filtering. Moreover, large motion artifacts disable the EMD to decompose respiratory components. In this paper, motion artifacts are detected and replaced by the data mirrored from the prior and the posterior before EMD processing. A novel intrinsic respiratory reconstruction index that considers both global and local properties of IMFs is proposed to define respiration-related IMFs for respiration reconstruction and instantaneous respiratory estimation. Based on the experiments performing a series of static and dynamic physical activates, our results showed the proposed method had higher cross correlations between respiratory frequencies estimated from thoracic impedance and those from oronasal airflow based on small window size compared to the Fourier transform-based method.

No MeSH data available.


Related in: MedlinePlus

Two thoracic impedance segments are corrupted by motion artifacts caused by postural change (a) and thoracic movement (b), respectively. Through the artifact detection and replacing, the region of the artifact is identified (highlighted by dashed lines), and the affected portion is replaced by the mirror data from the prior and posterior (c,d); The respirations are therefore reconstructed by the empirical mode decomposition-based method (e,f).
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sensors-15-16372-f004: Two thoracic impedance segments are corrupted by motion artifacts caused by postural change (a) and thoracic movement (b), respectively. Through the artifact detection and replacing, the region of the artifact is identified (highlighted by dashed lines), and the affected portion is replaced by the mirror data from the prior and posterior (c,d); The respirations are therefore reconstructed by the empirical mode decomposition-based method (e,f).

Mentions: Respiration-irrelevant thoracic movement will disturb the measured body impedance based on the change of thoracic volume. The scale and type of motion determine the disturbance’s intensity. Figure 4a shows an example of motion artifact caused by postural change. Figure 4b shows another example of motion disturbance induced by thoracic movement. Because EMD is a data-driven and self-adaptive method, large artifacts will interfere with EMD processing so that the respiration-related component cannot be distinctly captured by the IMFs. To overcome this difficulty, an artifact detection and replacing algorithm is proposed.


Instantaneous Respiratory Estimation from Thoracic Impedance by Empirical Mode Decomposition.

Wang FT, Chan HL, Wang CL, Jian HM, Lin SH - Sensors (Basel) (2015)

Two thoracic impedance segments are corrupted by motion artifacts caused by postural change (a) and thoracic movement (b), respectively. Through the artifact detection and replacing, the region of the artifact is identified (highlighted by dashed lines), and the affected portion is replaced by the mirror data from the prior and posterior (c,d); The respirations are therefore reconstructed by the empirical mode decomposition-based method (e,f).
© Copyright Policy
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC4541883&req=5

sensors-15-16372-f004: Two thoracic impedance segments are corrupted by motion artifacts caused by postural change (a) and thoracic movement (b), respectively. Through the artifact detection and replacing, the region of the artifact is identified (highlighted by dashed lines), and the affected portion is replaced by the mirror data from the prior and posterior (c,d); The respirations are therefore reconstructed by the empirical mode decomposition-based method (e,f).
Mentions: Respiration-irrelevant thoracic movement will disturb the measured body impedance based on the change of thoracic volume. The scale and type of motion determine the disturbance’s intensity. Figure 4a shows an example of motion artifact caused by postural change. Figure 4b shows another example of motion disturbance induced by thoracic movement. Because EMD is a data-driven and self-adaptive method, large artifacts will interfere with EMD processing so that the respiration-related component cannot be distinctly captured by the IMFs. To overcome this difficulty, an artifact detection and replacing algorithm is proposed.

Bottom Line: This measurement imposes little pressure on the body and uses the human body as the sensor, thereby reducing the need for adjustments as body position changes and making it suitable for long-term or ambulatory monitoring.Moreover, large motion artifacts disable the EMD to decompose respiratory components.A novel intrinsic respiratory reconstruction index that considers both global and local properties of IMFs is proposed to define respiration-related IMFs for respiration reconstruction and instantaneous respiratory estimation.

View Article: PubMed Central - PubMed

Affiliation: Department of Electrical Engineering, Hwa Hsia University of Technology, 111, Gongzhuan Rd., Zhonghe, New Taipei City 23568, Taiwan. wft.intuitive@seed.net.tw.

ABSTRACT
Impedance plethysmography provides a way to measure respiratory activity by sensing the change of thoracic impedance caused by inspiration and expiration. This measurement imposes little pressure on the body and uses the human body as the sensor, thereby reducing the need for adjustments as body position changes and making it suitable for long-term or ambulatory monitoring. The empirical mode decomposition (EMD) can decompose a signal into several intrinsic mode functions (IMFs) that disclose nonstationary components as well as stationary components and, similarly, capture respiratory episodes from thoracic impedance. However, upper-body movements usually produce motion artifacts that are not easily removed by digital filtering. Moreover, large motion artifacts disable the EMD to decompose respiratory components. In this paper, motion artifacts are detected and replaced by the data mirrored from the prior and the posterior before EMD processing. A novel intrinsic respiratory reconstruction index that considers both global and local properties of IMFs is proposed to define respiration-related IMFs for respiration reconstruction and instantaneous respiratory estimation. Based on the experiments performing a series of static and dynamic physical activates, our results showed the proposed method had higher cross correlations between respiratory frequencies estimated from thoracic impedance and those from oronasal airflow based on small window size compared to the Fourier transform-based method.

No MeSH data available.


Related in: MedlinePlus