Nitrous Oxide Oversedation — NDEB AFK MCQ

Correct answer: D — Euphoria progressing to dysphoria and disorientation

The progression of nitrous oxide effects follows a dose-response continuum. Initial signs (therapeutic level, 20-35%) include relaxation, tingling, and mild euphoria. As concentration increases beyond the therapeutic range, the patient transitions to dysphoria, disorientation, sweating, nausea, and potentially loss of protective reflexes. Euphoria that transitions to dysphoria (sweating, agitation, disorientation) is the key clinical sign that the sedation level is becoming too deep and the N₂O concentration should be reduced immediately.

Reference: Malamed – Sedation: A Guide to Patient Management, 6th ed., 2018