The use of a portable refractometer to measure desflurane

The measurement of volatile anaesthetic agents by infrared absorption is liable to interference by other gases which absorb infrared light. In particular, nitrous oxide may, in principle, interfere with the measurement of desflurane. On the other hand, the refractometer should be immune to such effects. We demonstrated that interactions may occur between desflurane and nitrous oxide with some gas analysers and that the refractometer remains a useful instrument.