If alveolar ventilation is `4200 mL//min`, respiratory frequency is `12` breaths per minute, and tidal volume is `500` mL, what is the anatomical-dead-space ventialtion ?

Options

A. `1800 "mL"//"min"`
B. `6000 "mL"//"min"`
C. `350 "mL"//"min"`
D. `1200 "mL"//"min"`

Explanation

To calculate the anatomical dead space ventilation, we can follow these steps:

### Step-by-Step Solution:

1. **Understand the Given Values**:
- Alveolar ventilation (VA) = 4200 mL/min
- Respiratory frequency (f) = 12 breaths/min
- Tidal volume (TV) = 500 mL

2. **Calculate Total Minute Ventilation (TMV)**:
- Total Minute Ventilation (TMV) is calculated using the formula:
\[ TMV = TV \times f \]
- Substituting the values:
\[ TMV = 500 \, \text{mL/breath} \times 12 \, \text{breaths/min} = 6000 \, \text{mL/min} \]

3. **Relate Total Minute Ventilation to Alveolar Ventilation and Dead Space Ventilation**:
- The relationship can be expressed as:
\[ TMV = VA + \text{Dead Space Ventilation (VD)} \]
- Rearranging gives us:
\[ VD = TMV - VA \]

4. **Calculate Dead Space Ventilation**:
- Now substituting the values we have:
\[ VD = 6000 \, \text{mL/min} - 4200 \, \text{mL/min} = 1800 \, \text{mL/min} \]

5. **Conclusion**:
- Therefore, the anatomical dead space ventilation is:
\[ \text{Anatomical Dead Space Ventilation} = 1800 \, \text{mL/min} \]

### Final Answer:
The anatomical dead space ventilation is **1800 mL/min**.

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