End tidal carbon dioxide measurement using an electro acoustic sensor.

Area of Science:

• Biomedical Engineering
• Sensor Technology
• Respiratory Physiology

Background:

• Accurate end-tidal carbon dioxide (CO2) monitoring is crucial for assessing respiratory function.
• Existing CO2 sensors can be expensive or lack rapid response times.
• Development of cost-effective, high-performance CO2 sensors is an ongoing need in medical diagnostics.

Purpose of the Study:

• To demonstrate a new electro-acoustic sensor for measuring end-tidal carbon dioxide (CO2).
• To evaluate the performance of this sensor against a reference device under various physiological conditions.
• To assess the sensor's response time for expiration.

Main Methods:

• An electro-acoustic sensor utilizing an acoustic resonator and a low-cost electro-acoustic element was designed.
• Simultaneous measurements were taken using the experimental device and a reference CO2 sensor.
• Testing involved subjects undergoing exercise, hypoventilation, and hyperventilation, covering a CO2 concentration range of 2.1 to 7.0 kPa.

Main Results:

• The experimental electro-acoustic CO2 sensor demonstrated strong correlation with the reference sensor (correlation coefficient = 0.976).
• The device exhibited a rapid response time for expiration, measured at less than 0.8 seconds.
• Performance was validated across a range of CO2 concentrations encountered during physiological challenges.

Conclusions:

• The developed electro-acoustic sensor provides a reliable and cost-effective method for end-tidal carbon dioxide (CO2) measurement.
• Its rapid response and good accuracy make it suitable for applications where high selectivity to other gases is not critical.
• This technology holds promise for non-invasive respiratory monitoring in various clinical and research settings.