Adverse Effects and Toxicity

For the most part, nitrous oxide/oxygen analgesia has very few adverse effects. Nausea and vomiting are the most common adverse effects found in 1-10% of patients and are associated with nitrous oxide concentrations in excess of 50% and multiple repeated fluctuations in concentration increases and decreases. Unlike general anesthesia, fasting is not required prior to administration, however patients may be advised to limit their food intake to a light meal within 2 hours of the appointment.

During clinical use for sedation at proper concentrations, nitrous oxide/oxygen has no toxic effects. Chronic exposure to nitrous oxide, especially recreational abuse, can produce neurotoxicity, impotence and renal and liver toxicity. There is concern that dental personnel exposed to high ambient air levels of nitrous oxide during patient treatment can exhibit toxicity. Dentists and dental personnel exposed to high levels of nitrous oxide for more than 3 hours per week exhibited an increase in liver disease. Therefore, gas leakage should be reduced as much as possible. This can be accomplished by:

  • Limiting patient mouth breathing through the use of rubber dam and minimal conversation between the patient and dental personnel.
  • Proper ventilation of the office environment and use to exhaust fans to eliminate ambient excessive nitrous oxide to the outside.
  • Inspecting equipment each day to ensure that tubing and bags are hole free and connections are tight.
  • Using a scavenger system when administering nitrous oxide with a flow rate adusted to 45L/min.
  • Selecting an appropriately fitting mask to ensure a proper yet comfortable seal.
  • Avoiding overfilling the reservoir bag.
  • Schedule periodic inspections of the complete system every 3 months to check for leaks.
  • Periodic monitoring of office personnel with the use of dosimetry badges.7