A new method of removing thorax impedance baseline wander by cubic spline interpolation

Bioimpedance signal is often influenced by baseline wander due to respiration, etc., which brings adversely effect to clinical analysis and measurement. In order to eliminate baseline wander of bioimpedance, a new method based on LabVIEW proposed to remove the baseline wander using cubic spline interpolation with fiducial points determined from valleys of bioimpedance wave after analyzing the advantages and disadvantages of existing methods. After eliminating the baseline wander, the bottom waveform of bioimpedance is very orderly, and the original signal is distortionless. The results in simulation and experimental measurement show that the proposed method is effective.