On the Detection of Propofol in Exhaled Air by MOS Gas Sensors

Bedside and non-invasive measurement of drugs in exhaled air within short time frames or even online could have a high therapeutic relevance. In this study, a commercially available metal oxide semiconductor (MOS) gas sensor, i.e. ENS160 from ScioSense, in temperature cycled operation (TCO) is studied for quantification of the intravenous anesthetic propofol. Propofol was chosen because a correlation of the plasma concentration to the concentration in exhaled air was already proven. A partial least regression model (PLSR) was built for quantification of propofol while suppressing the influence of humidity and ethanol as a main interferent. The root mean squared error (RMSE) of validation was as low as 4 ppb for a concentration range of 0 ppb to 40 ppb. The results suggest the usage of MOS sensor for drug monitoring.