Reserve nitrous oxide cylinders on anaesthetic machines. A survey of attitudes and equipment at a large DGH.

The presence of reserve nitrous oxide cylinders on anaesthetic machines is not necessary and potentially hazardous, wasteful and polluting. Although reserve nitrous oxide cylinders are routinely present on the anaesthetic machines in many hospitals in the UK, it is our concern that they are not checked or maintained properly. We examined a sample of cylinders and surveyed the practice amongst the anaesthetic staff in our Department with an anonymous questionnaire. This confirmed that: (1) the equipment is not properly maintained, 68% of cylinders sampled having passed a 3-year expiry date; (2) checks are of little practical use, are not routinely performed by anaesthetists, and only 46% of respondents routinely check the nitrous oxide cylinders. In conclusion, the nitrous oxide cylinders are not properly checked or maintained and may represent a safety hazard.