Respiratory Monitoring Based on Tracheal Sounds: Continuous Time-Frequency Processing of the Phonospirogram Combined with Phonocardiogram-Derived Respiration

Abstract

Patients with central respiratory paralysis can benefit from diaphragm pacing to restore respiratory function. However, it would be important to develop a continuous respiratory monitoring method to alert on apnea occurrence, in order to improve the efficiency and safety of the pacing system. In this study, we present a preliminary validation of an acoustic apnea detection method on healthy subjects data. Thirteen healthy participants performed one session of two 2-min recordings, including a voluntary respiratory pause. The recordings were post-processed by combining temporal and frequency detection domains, and a new method was proposed—Phonocardiogram-Derived Respiration (PDR). The detection results were compared to synchronized pneumotachograph, electrocardiogram (ECG), and abdominal strap (plethysmograph) signals. The proposed method reached an apnea detection rate of 92.3%, with 99.36% specificity, 85.27% sensitivity, and 91.49% accuracy. PDR method showed a good correlation of 0.77 with ECG-Derived Respiration (EDR). The comparison of R-R intervals and S-S intervals also indicated a good correlation of 0.89. The performance of this respiratory detection algorithm meets the minimal requirements to make it usable in a real situation. Noises from the participant by speaking or from the environment had little influence on the detection result, as well as body position. The high correlation between PDR and EDR indicates the feasibility of monitoring respiration with PDR.

Respiratory-Induced Amplitude Modulation of Forcecardiography Signals

“…As shown in Figure 2 and Figure 4 , the amplitude of the LF-FCG and HF-FCG signals appeared to be modulated by respiration. Various studies on SCG [ 8 , 9 , 30 , 31 , 32 ] and heart sounds [ 33 , 34 , 35 , 36 ] have found consistent variation in the amplitude of signals during various phases of the respiratory cycle, and nearly no variability during apnea. These results are consistent with those obtained from this study.…”

Clinical effect of pulmonary rehabilitation combined with diaphragm pacemaker therapy in the treatment of severely ill patients with mechanical ventilation

“…The above clinical research was consistent with our study, which illustrated that the EPR combined with EDP therapy could increase the activity of the diaphragm in patients, thereby ensuring the oxygen supply. At the same time, this treatment also promotes the recruitment of and maintains the proportion of diaphragmatic fibres and slows down diaphragmatic atrophy [28].…”

Cheyne-Stokes Respiration Perception via Machine Learning Algorithms

“…Lu's team proposed a method of breathing monitoring based on tracheal sounds called cardiac sound-derived respiration (PDR). They collected sound signals, then postprocessed the recordings in both the time domain and frequency detection domains, and finally compared them with electrocardiograms to detect apnea [15]. Preeti Jagadev et al used infrared imaging equipment to detect respiration by observing the temperature changes of the chest, neck, mouth and nose during respiration and extracting dynamic thermal eigenvalues, but this method was greatly affected by ambient temperature [16].…”