Exposure to trace amounts of nitrous oxide. Evaluation of urinary gas content monitoring in anaesthetic practice.

The urinary content of nitrous oxide was monitored during routine anaesthetic practice. There was a linear correlation with simultaneous measurements of technical exposure measured with a personal pump-bag sampling system (r = 0.99). Monitoring of urinary nitrous oxide with headspace extraction and gas chromatographic analysis is a simple and accurate mode of biological monitoring of exposure to nitrous oxide in the atmosphere.