Quantitation of sevoflurane in whole blood and aqueous solutions by volatile organic compound sensing

It is difficult to quantify poorly soluble volatile anesthetics in aqueous solutions; this necessitates the development of alternative prompt methods to analyze the in vivo blood concentrations of anesthetics for the clinical assessment of anesthesia depth. In this study, we demonstrated that the difficulties can be overcome by using volatile organic compound (VOC) sensors, which allow the levels of vaporized VOCs to be quantified in several seconds and obviate the need for conventional techniques such as gas chromatography or nuclear magnetic resonance (NMR).

The concentrations of a volatile general anesthetic (sevoflurane) in aqueous solutions containing human blood components and rabbit blood were measured using a VOC sensor and those in distilled water and phosphatidylcholine suspension were compared to those determined by NMR.

For all aqueous solutions with concentrations of up to 5 mM, the relationship between the VOC content and sevoflurane concentration was represented by a straight line passing through the origin. The concentration of sevoflurane determined by VOC sensing was well correlated with the values obtained by NMR at <1 mM, which is within the clinically relevant concentration levels.

Considering the results from this study, we can conclude that VOC sensing may be useful for measuring intraoperative blood anesthetic concentrations.