Nitrous oxide contraindications

The currently known contraindications to the use of nitrous oxide sedation include the following:

Breathing problems – Lung conditions

Inhalation sedation is not indicated for people with respiratory problems (asthma or emphysema) or difficulty breathing in through the nose. Patients with a cold are better to avoid inhalation sedation until they can breath normally. Nitrous oxide is given by a nose mask, so if patients are unable to breathe adequately through their noses, they will be unable to inhale sufficient nitrous oxide for sedation. Conditions relatively contraindicating the use of nitrous oxide include:

• Sinus infections (sinusitis)
• Nasal blocking conditions such as colds, influenza or allergies.
• Cystic fibrosis or
• Chronic obstructive pulmonary diseases (COPD) such as emphysema and bronchitis.

Mental conditions – Drug abuse

Some patients report that during nitrous oxide sedation they had dreams even though they were fully conscious. These potentially mind-altering effects of nitrous oxide may be a contraindication in patients with some mental or psychiatric disorders, patients with drug addictions, and patients under the influence of drugs or alcohol.

Patients suffering from severe phobias of any kind, or taking sleep-inducing medication, antidepressants, or psychotropic drugs are at high risk of having hallucinations when sedated with nitrous oxide. Because of the fact that dreams or hallucinations some patients have may be of sexual nature, a dentist will not perform nitrous oxide sedation when there is no other person present in the room, in order to avoid false abuse claims.

Patients with conditions that do not allow proper understanding of the procedure and maintaining communication with the dentist are not suitable for inhalation sedation dentistry, which is based essentially in the patient’s responsiveness to dentist’s questions and instructions.

First trimester of pregnancy

The first trimester of pregnancy is the most difficult period of pregnancy when most of the complications occur. Several researches have linked chronic occupational exposure to nitrous oxide with an increased percentage of pregnancy complications including spontaneous abortion among pregnant women working in places where nitrous oxide is administered. No risk have been found for pregnant patients sedated with nitrous oxide, provided that the dentist monitors closely the N2O/O2 mixture and does not allow oxygen levels fall below the safety level.

However dentists prefer not to use nitrous oxide sedation during the first trimester, and they will always request the patient’s physician or obstetrician consultation, to avoid any risk of their treatment being linked with the possibility of a patient’s pregnancy complications. In general it is recommended that dental treatments should be avoided in the first semester, except if absolutely necessary.