Environmental monitoring of nitrous oxide during dental anaesthesia

Aim The study was carried out to see if levels of nitrous oxide in dental t heatres and community dental clinics were being controlled in accordance wi th the Control of Substances Hazardous to Health Regulations. Setting A multi-centre study looked at exposure levels in a dental teaching hospital and two community dental clinics in the South Wales area between 1997 and 1998. Methods A MIRAN infra-red spectrophotometer was used to measure static leve ls of nitrous oxide during general anaesthesia and conscious sedation. NIOS H method 6600 was used to collect personal samples of the individual admini stering the anaesthetic. Results The results showed compliance with the regulations when averaged ou t over an 8 hour time weighted average. However, over short periods of time peak concentrations of up to 1190 ppm were observed through static samplin g, and up to 734 ppm through personal sampling. Conclusions The results highlighted the need to provide adequate control me asures such as anaesthetic gas scavenging, to reduce occupational exposure to dental staff in dental operating theatres and community dental clinics, therefore providing a safe working environment.