ArticleGu X, Zhao X, Mao Z, Shi Y, Xu M, Cai M, Xie F.
Comput Biol Med. 2022 06;145:105501.
Anesthetics inhibit the respiratory muscles and even cause upper airway to collapse. Diaphragm electromyography (EMGdi) and airflow signals are usually extracted to assess the degree of respiration inhibition by anesthetics. However, the ECG interference in EMGdi affects the accuracy of its time domain and frequency domain information extraction. We studied the changes in EMGdi (left EMGdi and right EMGdi) and airflow characteristics under two pentobarbital anesthetic doses. First, we filtered out the ECG in EMGdi based on the combination of stationary wavelet transform and the positioning of ECG to obtain EMGdi without ECG interference (EMGdip). The effectiveness of filtering algorithm was verified by calculating the power spectrum before and after noise reduction. Second, root mean square (RMS), average rectified value (ARV), and fixed sample entropy (fSampEn) were used to quantify EMGdi (left EMGdi, left EMGdip and right EMGdi). Median frequency (MF) and centroid frequency (fc) of EMGdi were calculated. Tidal volume, respiratory cycle duration and peak airflow were calculated from airflow. Finally, the average and standard deviation of these parameters for all rabbits (n = 10) were compared and analyzed under two anesthesia states. Our results indicate that anesthesia induced by an increase in pentobarbital dose leads to decrease in ventilation and EMGdi amplitude. There was no significant change in diaphragm power spectrum (MF and fc) with the increase of anesthesia dose.