Anaesthetic pollution in the dental out-patient surgery.

Five factors influencing pollution in the dental surgery are considered. Despite leakage from round the mask and from the mouth, scavenging can remove the majority of expired anaesthetic. The effectiveness of scavenging can usefully be monitored with a Wright respirometer. Spillage of anaesthetic vapour at induction and at the end of anaesthesia must be avoided. In addition to scavenging, pollution levels are minimised if a Boyle's type machine is used and excessive fresh gas flow avoided. Room ventilation, e.g. extract fans in windows, is vital in reducing pollution levels in the surgery. Room size and non-uniformity of ventilation must also be considered.