Page 128 - Color_Atlas_of_Physiology_5th_Ed._-_A._Despopoulos_2003

A. Measurement of dead space
Dead Space, Residual Volume, Airway Resist.
Alveolar part
of tidal Tidal
volume Dead space Mixing volume
VA volume VT
VD
FA CO 2 FI CO 2 FE CO 2

CO 2 volume
Dead space
Alveolar CO 2 + =
volume CO 2 volume in expired air
=
VA · FA CO 2 + VD·FI CO 2 VT · FE CO 2

VA =VT–VD FI CO 2 =0 Insert values

Bohr equation Using normal values:
) VD = 0.5 (0.056 – 0.040) Plate 5.5
VT (FA CO 2 – FE CO 2
Dead space VD = 0.056
Dead space VD = 143 mL
FA CO 2
B. Measurement of residual volume and functional residual capacity

VSp

FHe 0 FHe X

Mixing
VL

Helium volume Helium volumen
(in spirometer only) = (in lung and
spirometer)
=
VSp · FHe 0 (VSp+VL)·FHe X

. FHe 0 –FHe X VSp and FHe 0 are known
VL = VSp
FHe X FHe X : Measurement 115
Despopoulos, Color Atlas of Physiology © 2003 Thieme
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