The Effects of Scavenging on Waste Nitrous Oxide Concentrations in Veterinary Operating Room Air

Veterinarians, their assistants, and animal researchers should consider the potential health hazards of chronic exposure to the inhalational anesthetic, nitrous oxide. Recent studies suggest that long-term human exposure to nitrous oxide can be associated with increased general health problems and reproductive difficulties. These adverse human health effects include spontaneous abortion, congenital abnormalities, kidney disease, liver disease and neurologic disease. The exposure level of medical and dental personnel to nitrous oxide in operating and treatment room air is well documented. There are however, few reports of the potential hazard to veterinary personnel. This study was conducted to determine the exposure levels to nitrous oxide in a veterinary surgery. Real-time analyses were obtained utilizing infrared spectrophotometry. Measurements were made both during scavenging and not scavenging of the waste anesthetic gas. The mean level of nitrous oxide during scavenging was significantly different from the mean during not scavenging. Furthermore, the 95 percent upper confidence limit for the scavenged mean was within the 25 parts per million standard for nitrous oxide recommended by the National Institute for Occupational Safety and Health. The 95 percent upper confidence limit for the not scavenged mean was well above that standard. Protection of veterinary personnel and animal researchers from chronic exposure to nitrous oxide vapors, therefore, seems advisable and achievable. Complete waste anesthetic gas management and periodic monitoring programs should be established to protect personnel involved.