ATS Pulmonary Function Laboratory Manual

chapter  8

Appendix 8. 1 Calculations for FRC N2

= ( gas volume washed out ) × F N2 2 − ( N 2 volume from tissue ) F N2 1 − F N2 2

FRC N2

in the end-tidal air before the 1 st breath of washout in the volume of gas washed out at the end of the test

Where: F N2

1 = fractional concentration of N 2 2 = fractional concentration of N 2

F N2

Note: FRC N2

should be corrected to BTPS conditions and the volume of the equipment dead space subtracted. N 2 Tissues Excertion ( ml ) = ( BSA × 96 . 5 ) + 35 0 . 8

Where: BSA is body surface area in m 2 and determined by using:

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