Sniffing sevoflurane and propofol in exhalation from patients during balanced anesthesia

Sevoflurane and propofol are often used in combination to achieve a better anesthetic effect in balanced anesthesia. However, methods for on-line monitoring drug concentrations of the two anesthetics in patients are still scarce in clinic. This study proposed a non-invasive method utilizing a fast gas chromatograph (Fast GC) combined with a surface acoustic wave (SAW) sensor to simultaneously on-line monitor sevoflurane and propofol in patients' exhaled gas. Using the direct resistive heating capillary column, the analytical cycle time of the Fast GC-SAW system was significantly shortened to 90s, as well as the size was reduced.