The volume/capacity that can be measured by Hutchison’s spirometer is:
## **Core Concept**
Hutchison's spirometer is a device used to measure lung volumes, specifically designed to assess the lung's functional capacity. It is primarily utilized to measure volumes that can be exhaled or inhaled.
## **Why the Correct Answer is Right**
The Hutchison's spirometer is capable of measuring **tidal volume (TV)**, **inspiratory reserve volume (IRV)**, and **expiratory reserve volume (ERV)**. However, it cannot directly measure **residual volume (RV)**. The volume that can be measured by Hutchison's spirometer includes **Vital Capacity (VC)**, which is the sum of **TV**, **IRV**, and **ERV**. Vital Capacity is the maximum amount of air a person can expel from the lungs after a maximum inhalation.
## **Why Each Wrong Option is Incorrect**
- **Option A:** This option is incorrect because, although related, the specific combination or single volumes might not directly relate to what Hutchison's spirometer measures most directly or comprehensively.
- **Option B:** This option is incorrect for similar reasons; it might represent a different lung volume or capacity not directly measured by Hutchison's spirometer.
- **Option D:** This option is incorrect because it likely represents a volume or capacity not directly assessable by Hutchison's spirometer, such as **Residual Volume (RV)**.
## **Clinical Pearl / High-Yield Fact**
A key point to remember is that **Vital Capacity (VC)**, which can be measured by Hutchison's spirometer, is an important indicator of lung function. It is calculated as **VC = IRV + TV + ERV**. This measurement is crucial in assessing respiratory diseases and conditions.
## **Correct Answer:** C. Vital Capacity.