Calculate the Alveolar ventillation per minute of a patient with respiratory rate 14/min, tidal vol. 500 ml with a vital capacity 7000 ml, :
## Core Concept
Alveolar ventilation is the volume of air that reaches the alveoli and takes part in gas exchange per minute. It is calculated by subtracting the dead space volume from the tidal volume to get the alveolar tidal volume, then multiplying by the respiratory rate.
## Why the Correct Answer is Right
To calculate alveolar ventilation per minute, we first need to determine the alveolar tidal volume. This requires knowing the anatomical dead space, which is approximately 150 ml for an average adult.
Given:
- Respiratory Rate (RR) = 14/min
- Tidal Volume (Vt) = 500 ml
- Anatomical Dead Space (Vd) ≈ 150 ml (assumed, not given)
Alveolar Tidal Volume (VA) = Vt - Vd = 500 ml - 150 ml = 350 ml
Alveolar Ventilation per minute (VA/min) = VA * RR = 350 ml * 14/min = 4900 ml/min or 4.9 L/min
## Why Each Wrong Option is Incorrect
- **Option A:** Without calculation, we cannot assume this is correct or incorrect directly, but let's evaluate other options.
- **Option B:** Similarly, direct evaluation is not possible without calculation.
- **Option C:** This seems to match our calculation of 4.9 L/min, which equals 4900 ml/min.
- **Option D:** This option does not match any standard formula or calculation directly related to the given data.
## Clinical Pearl / High-Yield Fact
A key point to remember is that alveolar ventilation is a critical determinant of the effectiveness of breathing and directly impacts the levels of CO2 and O2 in the blood. The formula for alveolar ventilation (VA = Vt - Vd) * RR highlights the importance of both tidal volume and respiratory rate.
## Correct Answer Line
**Correct Answer: C. 4900.**