Definition
- Dead space is the space within the airways that does not allow gas exchange with pulmonary capillary blood.
- Normal anatomical dead space volume is 150 ml, out of a normal tidal volume of 500 ml.
Anatomical Dead Space
- Air within the conducting airways takes no part in gas exchange; because this is due to the structural (anatomical) arrangement of the airways, this volume is called anatomical dead space.
Dead space normal values
Parameter
Tidal volume
- Normal value
- 500 ml
Air reaching alveoli
- Normal value
- 350 ml
Anatomical dead space volume
- Normal value
- 150 ml
Dead space to tidal volume ratio
- Normal value
- 25 to 30%