Nitrogen Washout

1
(No Transcript)
2
(No Transcript)
3
(No Transcript)
4
(No Transcript)
5
(No Transcript)
6
Nitrogen Washout
Total volume expired x N2 Original volume of
N2 in lungs
Original volume of N2 in lungs x 1.25
Original lung volume
7
(No Transcript)
8
Helium Dilution
Amount of solute (mg) concentration of
solute (mg/ml) x volume of solvent (ml)
Total amount of He before test total amount of
He at end of test
9
(No Transcript)
10
BODY PLETHYSMOGRAPH

• PBOX x VBOX PBOX x (VBOX - ?V)

i
i
f
i
where (VBOX - ?V) VBOX
i
f

• PM x VL PM x (VL ?V)

i
i
f
i
where (VL ?V) VL
i
f
11
ANATOMIC DEAD SPACE
12
(No Transcript)
13
PHYSIOLOGIC DEAD SPACE
Physiologic Dead space
Anatomic Dead space
Alveolar Dead space


14
BOHR EQUATION DERIVATION
FE x VT Fi x VD FA x
VA
CO2
CO2
CO2
CO2
The volume of CO2 in mixed expired air
The volume of CO2 coming from dead space
The volume of CO2 coming from alveoli
Where F fractional concentration E mixed
expired I inspired A alveolar
15
Substituting (VT VD ) for VA
CO2
16
FA - FE
VD
CO2
CO2
CO2

FA
VT
CO2
Pa - PE
VD
CO2
CO2
CO2

VT
17
(No Transcript)
18
Bohr Equation
Pa - PE
VD
CO2
CO2
CO2

VT
19
.
.
VE VA x FA
.
CO2
CO2
V VA
CO2
FA ?
.
CO2
Since
FA x (760 47) PA
CO2
CO2
.
V VA
CO2
Then PA ?
.
CO2
20
(No Transcript)
21
( PB - PH O) -
22
(No Transcript)
23
(No Transcript)
24
(No Transcript)
25
(No Transcript)
26
(No Transcript)
27
Nitrogen Concentration
Expired volume, L
28
(No Transcript)