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 more than 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.

For routine clinical use, and at proper concentrations, nitrous oxide/oxygen has no toxic effects. Chronic exposure to nitrous oxide, especially recreational abuse, can produce neurotoxicity, impotency, renal and liver toxicity. There is concern those 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 has been shown to exhibit toxicity. Therefore, gas leakage should be reduced as much as possible. This can be accomplished by:

• Limit patient mouth breathing using 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.

• Inspect equipment each day to ensure that tubing and bags are free of damages and connections are tight.

• Using a scavenger system when administering nitrous oxide with a flow rate adjusted to 45L/min.

• Select an appropriately fitting mask to ensure a proper yet comfortable seal.

• Avoid 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