End tidal carbon dioxide measurement using an electro acoustic sensor.
End tidal carbon dioxide measurement with an electro-acoustic sensor is demonstrated. The sensor consists of an acoustic resonator coupled to a low cost electro-acoustic element. By simultaneous measurements with a reference sensor, the new device was tested on subjects performing exercise, hypo- and hyperventilation whereby the CO<inf>2</inf>concentration ranged from 2.1 to 7.0 kPa. The output from the experimental device correlated well with the reference CO<inf>2</inf>readings with a correlation coefficient of 0.976. Response time for expiration less than 0.8 seconds was noted. The new device could be useful in situations where selectivity to other gases is not important.
Folke
M
M
Department of Electrical Engineering, Mälardalen University, Västerås, Sweden.
Hok
B
B
Ekstrom
M
M
Backlund
Y
Y