Does medical nitrous oxide need to be scavenged? If so, how?

Nitrous oxide is an extremely safe medicinal gas when used appropriately and with the correct scavenging equipment and air exchange rates. The current UK exposure levels of a 100ppm (based on an 8hour time weighted average) are easily achieved when these systems are adopted.

Therefore nitrous oxide should be administered in rooms with suitable ventilation and/or scavenging equipment. It should be administered at the lowest effective flow to avoid waste and ecological consequences.

It has been demonstrated that, “as long as routines for gas scavenging, in line with occupational limits, are followed, there is insufficient evidence to recommend any routine medical surveillance of personnel exposed to trace concentrations of waste anaesthetic gases” (1)

Nitrous oxide is predominantly used as a background anaesthetic agent and as such would be used within the theatre setting which would allow scavenging to take place. In areas where it might be used outside of theatre such as the MRI suite then good ventilation must be ensured and exposure should be kept to a minimum. There are portable scavenging systems available for use in areas where ventilation may be restricted.

References:

(1) McGregor DG, Baden JM, Bannister C et al. Task force on anesthetic gases – Information for management in anesthetizing areas in a post-anesthetic care unit (PACU). American Society of Anesthesiologists – 1999 – Park Ridge, IL - USA