An Investigation of Contamination with Nitrous Oxide(N2O) in Operating and Recovery Rooms Atmosphere

Chronic exposure to N2O environmental pollution may influence the health of personnel working in operating and recovery rooms. Human studies have indicated that chronic exposure to N2O may decrease mental performance, audiovisual ability, and manual dexterity and may also cause adverse reproductive effects like reduced fertility, spontaneous abortion and neurological, renal, and liver diseases. In this study, concentration of N2O in ambient air was monitored in 45 operating rooms and 12 recovery rooms at 12 hospitals. Ambient air was sampled automatically from three breathing sites in operating room(anesthetists, surgeons, operating room nurse) and one site in recovery room(recovery nurse) using a portable infrared spectrophotometer(N2O monitor 3010) with ppm mode. In addition, the effect of air ventilation system on the outcomes was measured. Statistical analysis of the data demonstrated that mean exposure of operating rooms was significantly lower in ventilated than unventilated rooms(P<0.05). Anesthetists showed higher mean exposure than other staff in all conditions, and operating room nurse showed lowest mean concentration. The breathing zone anesthetic concentration of N2O in 100% of sampling exceeded NIOSH recommended exposure limit(REL) for N2O (25ppm). Our data showed that exposure of recovery nurses to N2O was higher than REL of NIOSH but there was not any significant correlation between room air ventilation and the outcomes(P>0.05). In conclusion, proper use of air ventilation, anesthetic gases and scavenging system are necessary for having limited contamination with N2O.