1. Nitrous Oxide Hazards and Proper Use College of Dental Medicine

2. What is Nitrous Oxide?
Nitrous oxide (N20) is nonflammable, colorless gas with pleasant, sweet odor and taste
Also called dinitrogen monoxide or laughing gas
When inhaled, it produces relaxation, and a reduced sensibility to pain

3. Uses Anesthetic agent in dental, medical and veterinary operations
Analgesic agent for conscious sedation in dental operations
Other uses include foaming agent for whipped cream and component of rocket fuels

4. Exposure Routes & Safe Limits
Inhalation – common exposure route
Dermal – in liquid form
NIOSH: 25 ppm time-weighted average for duration of use
ACGIH: 50 ppm time-weighted average for 8 hour of use

5. Metabolism Mixed with oxygen for surgical anesthesia
Absorbed by diffusion through inhalation
Eliminated through respiration
Elimination half-life is ~ 5 minutes
Minimally metabolized through excretion

6. Health Effects Exposure to high concentrations may cause
Acute Effects:
Breathing difficulty and asphyxia from abuse by inhalation
Nausea or Headache
Vitamin B12 interference
Frostbite in liquid form
Chronic Effects:
Megaloblastic bone-marrow depression
Neurological symptoms
Adverse reproductive effects

7. Potential for Exposure in Dental Clinics
Inadequate Ventilation Systems
Inadequate Scavenging Systems
Equipment Malfunction
Equipment failure
Leaks due to poor connections
Poor Technique or Use
Uncooperative Patient

8. Exposure Controls Engineering Controls
General room ventilation provides 12 air changes per hour hence keeping the Nitrous Oxide concentration <25ppm
Scavenging system used when administering N2O captures all exhaled and unused gas and keeps out of the office area thereby protecting you
Report any damage and non-functional scavenging and ventilation systems

9. Exposure Controls
Proper work practices, training, patient and equipment management are part of administrative controls and contribute to controlling N2O exposure to you
Inspect delivery system prior to N2O administration
Check connections, breathing bags, hoses and clamps.
Do not fill breathing bag to capacity
Over inflation can cause excessive leakage from the mask
The bag should collapse and expand as the patient breathes
Flush the system of N2O after the procedure by administering O2 to the patient for five minutes before disconnecting the gas delivery system
Improper Fit
Proper Fit

10. Exposure Assessments
Surveys performed by consultant to ensure systems are working properly and-
Nitrous oxide levels are < 5ppm
Air changes are adequate (> 10ACH) in rooms
All rooms are confirmed to be under negative pressure