Practical Acoustic Energy-Based Estimation of Inhalation Flow Rate for Asthma Monitoring

Area of Science:

• Biomedical Engineering
• Acoustic Signal Processing
• Respiratory Medicine

Background:

• Inhalation flow rate (IFR) estimation using acoustic devices is gaining traction.
• Current methods often assume a fixed microphone distance, limiting real-world applicability.
• Variable distances significantly impact acoustic energy, leading to inaccurate IFR estimations.

Purpose of the Study:

• To develop a method for accurate IFR estimation independent of microphone distance.
• To utilize the inhaler actuation sound as a reference signal for distance estimation.
• To validate the proposed method's accuracy in real-world scenarios.

Main Methods:

• Exploiting the passive acoustic signal generated during inhaler actuation.
• Using the actuation sound as a reference to estimate the distance between the device and the microphone.
• Implementing a single-microphone system for distance and IFR estimation.

Main Results:

• Successfully estimated the distance using the inhaler actuation sound.
• Achieved highly accurate inhalation flow rate estimation.
• Demonstrated a coefficient of determination (R²) of 80.3% for IFR estimation.

Conclusions:

• The proposed method enables accurate IFR estimation even with variable microphone distances.
• Leveraging inhaler actuation sound is a viable strategy for distance compensation in acoustic IFR monitoring.
• This approach enhances the reliability of acoustic devices for respiratory monitoring.