Implementation of gas sampling chamber and measuring hardware for capnograph system considering thermal noise effect and time response characteristics

Author

Park, I.Y. ; Lee, S.K. ; Park, H.J. ; Kang, K.M. ; Song, B.S. ; Kang, S.W. ; Cho, J.H.

Author_Institution

Sch. of Electr. Eng. & Comput. Sci., Kyungpook Nat. Univ., Taegu, South Korea

Volume

4

fYear

2001

fDate

2001

Firstpage

3296

Abstract

Most capnograph systems that can indirectly determine the partial pressure of carbon dioxide in the blood of a patient are based on NDIR (non-dispersive infrared) absorption technology. As such an NDIR gas analyzing method requires an optical absorption chamber and signal processing hardware. Accordingly, this paper designed and implemented an NDIR type CO₂ gas chamber while considering the time response characteristics and lamp chopping frequency. In addition, signal processing hardware using two infrared sources was implemented to reduce the thermal background effect. The gas chamber and signal processing hardware has been tested using temperature variation and human expiration experiment. The results showed that the system could produce a stable output signal and discerning CO₂ gas concentration curve similar to a typical capnogram.

Keywords

bio-optics; biochemistry; biomedical equipment; biomedical measurement; blood; carbon compounds; light absorption; noise; CO₂; NDIR type CO₂ gas chamber; capnograph system; human expiration experiment; infrared sources; lamp chopping frequency; optical absorption chamber; optical gas chamber; partial pressure; signal processing hardware; stable output signal; temperature variation; thermal background effect; thermal noise effect; time response characteristics; Blood; Carbon dioxide; Electromagnetic wave absorption; Hardware; Noise measurement; Optical noise; Optical signal processing; Sampling methods; Time factors; Time measurement;

fLanguage

English

Publisher

ieee

Conference_Titel

Engineering in Medicine and Biology Society, 2001. Proceedings of the 23rd Annual International Conference of the IEEE

ISSN

1094-687X

Print_ISBN

0-7803-7211-5

Type

conf

DOI

10.1109/IEMBS.2001.1019529

Filename

1019529