Question

Which mixture of gases are used in anesthesia?

• A. \( \text{O}_2 \text{ and CO}_2 \)
• B. \( \text{O}_2 \text{ and N}_2\text{O} \)
• C. \( \text{CO}_2 \text{ and N}_2\text{O} \)
• D. \( \text{O}_2\text{, CO}_2 \text{ and N}_2\text{O} \)

Hint:

Oxygen (\( \text{O}_2 \)) is always administered with inhaled anesthetics to ensure adequate oxygenation of the patient's blood. Nitrous Oxide (\( \text{N}_2\text{O} \)), also known as "laughing gas," is a weak anesthetic but a potent analgesic, often used as a carrier gas for more potent volatile anesthetics or alone for minor procedures.

Answer 1

The Correct Option is B

To solve this problem, let's analyze the gases used in anesthesia and their specific roles in the anesthetic mixture.

1. Understanding Anesthetic Gas Mixtures

Anesthesia typically uses a combination of gases to achieve three main objectives: 
- Oxygen (O₂) for maintaining oxygenation - Anesthetic agents (like nitrous oxide) for sedation/analgesia 
- Sometimes carbon dioxide (CO₂) in very specific situations

2. Analysis of Each Option

O₂ and CO₂:

Incorrect. While oxygen is essential, CO₂ is not typically used as an anesthetic gas. CO₂ is a respiratory byproduct that the body needs to eliminate.

O₂ and N₂O:

Correct. This is the most common anesthetic gas combination. Oxygen is always required, and nitrous oxide (N₂O) is a widely used anesthetic gas that provides analgesia and mild sedation.

CO₂ and N₂O:

Incorrect. This mixture lacks oxygen, which would be dangerous for the patient. CO₂ is not an anesthetic agent.

O₂, CO₂ and N₂O:

Partially correct but misleading. While O₂ and N₂O are used, CO₂ is not normally added to anesthetic mixtures as it's a waste product the body tries to eliminate.

3. Why O₂ and N₂O is the Correct Answer

This combination is commonly used because: - O₂ maintains proper oxygenation - N₂O provides analgesic effects - The mixture is stable and predictable - It allows for rapid induction and recovery

4. Clinical Considerations

Modern anesthesia often uses: - Oxygen as the carrier gas - Nitrous oxide for its analgesic properties - Volatile anesthetic agents (like sevoflurane) for deeper anesthesia - Never CO₂ unless in very specific experimental situations

5. Final Answer

The correct mixture of gases used in anesthesia is O₂ and N₂O, as this provides both oxygenation and anesthetic effects.