Cyclopropane and the Datex Capnomac. Effect of cyclopropane on the single wavelength infrared measurement of volatile anaesthetic agents.

We report the effect of cyclopropane used for induction of anaesthesia in children on the subsequent measurement of maintenance volatile anaesthetic agents with the single wavelength infrared absorption technique. After using cyclopropane to induce anaesthesia we have observed that falsely high readings of the expired maintenance agent occur for up to 60 minutes when using the Datex Capnomac. This is because of the effect of low concentrations of cyclopropane expired from the patient.