**Question:** A person is having normal lung compliance and increased airway resistance. The most economical way of breathing for him

A. Increase tidal volume
B. Maintain tidal volume while decreasing respiratory rate
C. Decrease tidal volume while increasing respiratory rate
D. Increase inspiratory time

**Core Concept:**

In the context of the question, understanding the relationship between lung compliance, airway resistance, and breathing efficiency is crucial. Lung compliance refers to the ease with which the lungs can expand and contract, while airway resistance is the opposition to air flow in the airways. In this scenario, the person has normal lung compliance, meaning the lungs can expand and contract easily, and increased airway resistance, indicating narrower airways that hinder airflow. The goal is to find the most economical way to breathe, which means finding the combination of tidal volume and respiratory rate that consumes the least energy while maintaining adequate gas exchange.

**Why the Correct Answer is Right:**

When dealing with increased airway resistance, the body attempts to compensate by adjusting tidal volume and respiratory rate to maintain oxygenation and carbon dioxide removal. In this case, the most economical way to breathe is to **decrease tidal volume while increasing respiratory rate**. This is because:

1. Decreasing tidal volume reduces the work of breathing, as less force is required to move air through the narrower airways. This reduces energy consumption and allows the person to breathe more efficiently.
2. Increasing respiratory rate helps to compensate for the decreased tidal volume, ensuring adequate gas exchange. A higher respiratory rate allows for a greater number of breaths per minute, increasing the overall amount of gas exchange and maintaining oxygenation and carbon dioxide removal.

**Why Other Options are Incorrect:**

Option A (increase tidal volume) is incorrect because increasing tidal volume would increase the work of breathing due to the narrow airways, and may not effectively improve gas exchange.

Option B (maintain tidal volume while decreasing respiratory rate) is incorrect because decreasing respiratory rate would lead to inadequate gas exchange, as the overall amount of gas exchange decreases with fewer breaths per minute.

Option C (decrease tidal volume while decreasing respiratory rate) is incorrect, as this combination would also result in inadequate gas exchange due to decreased tidal volume and respiratory rate.

**Additional Information and Clinical Pearls:**

In clinical scenarios, understanding this concept is essential for managing patients with respiratory issues, particularly those with obstructive airway diseases like asthma or chronic obstructive pulmonary disease (COPD). By optimizing tidal volume and respiratory rate according to the situation, healthcare professionals can help patients breathe more efficiently, reducing work of breathing and maintaining adequate gas exchange. Adequate ventilation is vital for oxygenation, which is crucial for tissue perfusion and overall systemic circulation.