Anesthesia · single question
Nitrous oxide (N₂O) is CONTRAINDICATED in all of the following EXCEPT:
Show answer and explanation
Correct answer: D. Mild dental anxiety in a cooperative adult patient
✓ D) Mild dental anxiety in a cooperative adult = INDICATION, not contraindication.
N₂O INDICATIONS: mildly apprehensive/anxious patients, frightened children, gag reflex control, reduce stress, when requested by patient. ABSOLUTE contraindications: nasal obstruction, inability to communicate, increased intracranial pressure, substance abuse history. RELATIVE contraindications: COPD/pulmonary disease (impairs oxygen delivery), respiratory infections (nasal obstruction), pregnancy (especially first trimester — N₂O inhibits methionine synthase, teratogenic concern), multiple sclerosis, psychiatric patients, blocked middle ear. URI/COPD/Pneumonia are all contraindications.
N₂O INDICATIONS: mildly apprehensive/anxious patients, frightened children, gag reflex control, reduce stress, when requested by patient. ABSOLUTE contraindications: nasal obstruction, inability to communicate, increased intracranial pressure, substance abuse history. RELATIVE contraindications: COPD/pulmonary disease (impairs oxygen delivery), respiratory infections (nasal obstruction), pregnancy (especially first trimester — N₂O inhibits methionine synthase, teratogenic concern), multiple sclerosis, psychiatric patients, blocked middle ear. URI/COPD/Pneumonia are all contraindications.