Detection of Respiratory Crackles and Respiration Phase Using a Wearable MEMS Contact Microphone

Crackles are an important adventitious lung sound often detected in patients with obstructive lung diseases, including COPD, pulmonary fibrotic disorders like interstitial lung diseases (ILDs), as well as patients with decompensated heart failure and pneumonia. Here, we use a wearable patch consisting of a sensitive silicon contact microphone chip to capture simultaneously the pulmonary induced vibrations (PIVs) from the chest walls of patients with COPD and pulmonary fibrotic lung disease, along with their chest wall movement for breathing pattern. The wearable patch has shown high fidelity in capturing crackles along with their correlation with the respiratory phase, where the correlation can be used as an indicator of respiratory diseases. Crackles from patients of high body mass index (BMI) were also captured as shown in the contact microphone PIVs mel spectrograms. From the recordings, we have captured coarse and fine crackles, which were found to correlate with a patient with COPD and a patient with interstitial fibrosis, respectively.