Assessment of a scavenging device for use in paediatric anaesthesia.

We describe a scavenging device, primarily for use during inhalation induction of anaesthesia in children; it was designed to optimize the often conflicting requirements of clinical acceptability and adequate gas collection. The performance was assessed in three ways. The device reduced the nitrous oxide concentration in the breathing zone of the anaesthetist during inhalation induction to about 100 p.p.m. We also describe a method to measure the direct catchment of nitrous oxide expressed as a percentage of the total nitrous oxide used. In 46 patients the mean percentage collection was 82%. Using personal sampling devices, we found that comprehensive scavenging in paediatric anaesthesia can reduce the average exposure of anaesthetists to about 130 p.p.m. of nitrous oxide.