Anesthetic pungent odor requiring a vaporizer?

• A. Isoflurane
• B. Nitrous oxide
• C. Desflurane
• D. Sevoflurane

Answer: (C)

Desflurane is the inhaled anesthetic that fits this description. It has a distinctly pungent, airway-irritating odor, which is why it can provoke coughing or bronchospasm if used for mask induction. Its physical properties are unique among commonly used agents: it has an extremely high vapor pressure at room temperature, so it must be delivered with a specialized heated, agent-specific vaporizer to regulate the concentration accurately. Conventional vaporizers aren’t suitable for desflurane because of these requirements.

For context, nitrous oxide is a nonpungent gas and doesn’t rely on a liquid vaporizer; sevoflurane has a pleasant odor and is favored for induction, and isoflurane is pungent but doesn’t require the special desflurane vaporizer. The combination of a pungent odor and the need for a dedicated vaporizer points to desflurane.