Potential inaccuracies in mass spectrometers with spectrum overlap erasure units used during anaesthesia.

Cracking pattern overlap effects have been identified as one of the major sources of measurement error in the use of mass spectrometers in anaesthesia. Spectrum overlap erasure units, which subtract from one signal peak a portion of another peak, have been used to eliminate overlap due to cracking pattern. Using a computer simulation, the efficacy of various spectrum overlap erasure configurations with associated automatic sensitivity controls has been studied. The effect of noise and changes in cracking pattern have been assessed. Accuracies predicted by the simulation have been compared with an arbitrary standard of accuracy (0.1% vol/vol), for a selection of gases commonly encountered in clinical anaesthesia.