**Question:** A 38-year-old man is scheduled for the extraction of his last molar tooth under general anaesthesia as a day care case. He intends to return to work after 6 hours. Which one of the following induction agents is preferred?

A. Propofol
B. Thiopentone
C. Sevoflurane
D. Desflurane

**Correct Answer: B. Thiopentone.**

**Core Concept:** Induction agents are drugs used to induce general anaesthesia by facilitating loss of consciousness and muscle relaxation. They are classified as short, intermediate, or long-acting agents based on their duration of action.

**Why the Correct Answer is Right:** Thiopentone (phenytoin) is a short-acting barbiturate induction agent that provides rapid onset and short duration of action, making it suitable for day care cases. It is also characterized by minimal cardiovascular and respiratory depression, minimizing the risk of complications in a day care setting.

**Why Each Wrong Option is Incorrect:**

A. **Propofol (Diprivan):** Although propofol is a short-acting induction agent, it has a longer duration of action than thiopentone and might cause more cardiovascular and respiratory depression, making it less suitable for a day care setting.

B. **Sevoflurane (Forane):** Sevoflurane is a long-acting inhalational induction agent, providing longer duration of action and more significant cardiovascular and respiratory depression. This makes it less suitable for a day care setting.

C. **Desflurane (Evoline):** Similar to sevoflurane, desflurane is also a long-acting inhalational induction agent with longer duration of action and more significant cardiovascular and respiratory depression. It is not the preferred choice for a day care setting.

**Clinical Pearl:** Choosing the right induction agent for a day care setting is essential to minimize complications and ensure a smooth recovery. Thiopentone's favorable properties, including rapid onset, minimal cardiovascular and respiratory depression, and shorter duration of action, make it the preferred induction agent for this scenario.