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nitrogen washout
Indications:
- measurement of anatomic dead space in the lung during a respiratory cycle
- estimation of functional residual capacity & absolute lung volume
Procedure:
- a single nitrogen breath, or multiple breaths
- breath of 100% oxygen with exhalation through a one-way valve
- nitrogen content & volume are measured
- a plot of the nitrogen concentration vs expired volume is obtained that shows increasing nitrogen concentration from zero to the % of nitrogen in the alveoli*
* the nitrogen concentration is initially zero because the subject is exhales the dead space oxygen they just breathed in
General
pulmonary function test (PFT)
References
- Wikipedia: Nitrogen washout
https://en.wikipedia.org/wiki/Nitrogen_washout