Question

How do you measure respiratory volume?

Answer 1

Respiratory volume:

1. Respiratory volume, also called as lung volume or lung capacity, is the volume of gas in the lungs at a given time during the respiratory cycle.
2. The adult average total lung capacity is approximately 6 liters of air.
3. Example: tidal volume, inspiratory reserve volume, residual volume

Techniques to measure respiratory volume

1. Spirometry - The patient is required to breathe into a mouthpiece of an instrument called a spirometer, which measure the amount of air breathed.
2. Plethysmography - The person is asked to sit in an airtight box and breathe through a mouth piece. The pressure change inside the box is monitored to help determine the lung volume.
3. Lung capacity is measured by breathing a harmless gas (nitrogen/helium) through a tube connected to a chamber for some time. The concentration of the gas in the chamber is measured to calculate the lung volume.