Comparison of a micro-electro-mechanical system airflow sensor with the pneumotach in the forced oscillation technique

Abstract

Purpose

This study supports the use of thin-film micro-electro-mechanical system (MEMS) airflow sensors in the forced oscillation technique.

Materials and methods

The study employed static testing using air flow standards and computer-controlled sound attenuations at 8 Hz. Human feasibility studies were conducted with a testing apparatus consisting of a pneumotach and thin-film MEMS air flow sensors in series. Short-time Fourier transform spectra were obtained using SIGVIEW software.

Results

Three tests were performed, and excellent correlations were observed between the probes. The thin-film MEMS probe showed superior sensitivity to higher frequencies up to 200 Hz.

Conclusion

The results suggest that lower-cost thin-film MEMS can be used for forced oscillation technique applications (including home care devices) that will benefit patients suffering from pulmonary diseases such as asthma, COPD, and cystic fibrosis.

Keywords:

• pulmonary disease
• pulmonary impedance
• airway resistance
• short-time Fourier transform
• glottis closure

Acknowledgments

Sensors were fabricated at the Princeton Institute for the Science and Technology of Materials, an interdisciplinary research center at Princeton University. Calibration work was performed at Boston University’s Respiratory and Physiological Systems Identification Laboratory. Feather Sensors, LLC (Millville, NJ, USA) is the manufacturer of the MEMS sensor system that was used in this study. We thank Larry Ericksen and Patrick Lichter for their insights and comments on the preparation of this manuscript.

This work was supported by the National Science Foundation under SBIR Grant 1248714.

Author contributions

CEF, REC, SLM, BDG, and KRL participated in the conception and design of research. XKX, BPH, KRL, SLM, and CEF performed experiments, and XKX prepared sensors and probes. All authors contributed to data analysis, critically revising the paper, and agree to be accountable for this work.

Disclosure

CEF and REC are the owners of Feather Sensors, LLC, and XKX and SLM were employees of Feather Sensors, LLC at the time of this work. BPH was a graduate student of KRL (Boston University) during this work. The authors report no other conflicts of interest in this work.