Got Nitrous Oxide? Safety and Maintenance is No Laughing Matter

We’ve been getting lots of questions lately about the safety and required maintenance of nitrous oxide equipment, so we thought it would be good to provide a refresher on best practices:

Safety

• Inhalation equipment:
  • Must have the capacity for delivering 100%, and never less than 30%, oxygen concentration at a flow rate appropriate to the child’s size.
    • If equipment capable of delivering more than 70 percent nitrous oxide and less than 30 percent oxygen is used, an inline oxygen analyzer must be used.
• Fail-Safe System:
  • Must be installed so that the nitrous oxide supply will be turned off automatically when oxygen delivery is compromised or depleted.
  • Check and calibrate regularly according to state laws and regulations.
• Scavenging system:
  • Must be installed and working appropriately to minimize room air contamination and occupation risk.
  • Exhaust ventilation of nitrous oxide from the patient’s mask should be maintained at an air flow rate of 45 LPM, measured by a calibrated flow device, and vented outdoors — not into the room ventilation system.
  • Sample the air periodically (e.g., every four months) to measure personal breathing zone exposures of employees, detect leaks in the delivery system, or ineffective capture by the scavenging system.  The following sampling methods may be used:
    • Real-Time Sampling: 
• Utilizes a portable Infrared Gas Analyzer (IGA) to provide continuous sampling and instantaneous feedback
• Time-Integrated Sampling:
• Bag Sampling:  Sample for a selected time period during the time of nitrous oxide administration to the patient.  This is accomplished by collecting an integrated air sample in a plastic bag, using a portable battery-powered pump.  Analysis of the bag sample is accomplished using the IGA.  The nitrous concentration obtained is an average value for the entire sampling period; or 
• Diffusive Sampler:  Using a passive dosimeter, nitrous oxide levels can be collected and sent to a commercial laboratory for analysis. The dosimeter attaches to the employee’s lapel and is uncapped/recapped during the actual administration of nitrous oxide.  

• System Components – Routine Checks:
  • Prior to First Use Each Day and Whenever a Gas Tank is Changed:
    • Check low pressure connections for leaks
    • Check reservoir bag, lines, face masks and connectors for cracks, wear, holes or tears (any of which should be repaired or replaced immediately)
    • Check that the alarm is working
    • Check Fail-Safe system for proper function
  • Quarterly: Test high-pressure line connections for leaks by applying a non-oil based soap solution to the lines and connections to see if there are air bubbles.  You can also use a portable infrared spectrophotometer to test these connections. 
• Emergency Drug Kit – Keep Nearby:
  • Must include equipment to resuscitate a non breathing, unconscious patient.
• Oxygen Tank – Keep Nearby:
  • Must be capable of administering greater than 90% oxygen at a 10 L/min flow for at least 60 minutes (650 L, “E” cylinder).

Maintenance 

• Delivery and Scavenging Systems – Annual Inspections (generally):
  • Compliance with National Fire Protection Association (NFPA) 99 is mandated by applicable regulatory agencies
    • NFPA 99 requires verification testing for new, modified, or repaired compressed air systems and subsequent testing per manufacturer’s recommendations, often annually. 
    • Testing/analysis should be performed by a party other than the installer.  Look for companies that have American Society of Safety Engineer (ASSE) 6030 qualified employees.