Anesthesia · single question
During sedation, SpO₂ drops below 92%. What is the most likely cause?
Show answer and explanation
Correct answer: A. Airway obstruction
- A. Correct. Desaturation under sedation most commonly reflects a compromised/obstructed airway or hypoventilation; head-tilt/chin-lift and oxygen are the first responses.
- B. Hyperventilation lowers CO₂ and typically maintains or raises oxygenation, not the cause of desaturation.
- C. Bradycardia is a heart-rate change; it may follow hypoxia but is not the primary cause of falling SpO₂.
- D. Nitrous oxide itself is not toxic at clinical concentrations; diffusion hypoxia is prevented with 100% O₂ at the end.