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Flashcards in Ventilation Deck (24):
1

define alveolar ventilation

rate at which air actually reaches alveoli

2

2 requirements of vent

1. air must reach alveolus
2. lung must be perfused

3

only way to secrete CO2

increase vent

4

2 things which CO2 excretion depends on

1. rate of alveolar vent
2. pACO2

5

how to assess paCO2

K(VCO2/VA)

6

name for area without alveoli

dead space

7

definition of resistance

change in pressure/flow

8

formula for resistance (poiseuilles law)

(8 x viscosity x length)/radius to the 4th

9

most important factor in resistanct

radius (to the 4th)

10

formula for resistance in series

R = R1 + R2 + R3...

11

formula for resitiance in parralell

1/R = 1/R1 + 1/R2 + 1/R3

12

normal volume of dead space

150ml

13

how to measure dead space

one breath of 100% O2 and measure N2 breathed out
- dead space = volume of 0% N2 and 1/2 of mixed volume

14

definition of alveolar dead space

anatomic dead space + unperfused portions of alveoli

15

normal ratio of dead space to tidal vol.

0.2 -0.35

16

formula to measure ratio of dead space to tidal vol

VD / VT = (PACO2-PECO2)/PACO2

17

where does gas come from in alveolus

mix of venous gases and airway gases

18

formula for alveolar air equations

PAO2 = PIO2 – (PaCO2/0.8)

19

what is A-a gradient

measure of PA02 to PaO2

20

normal PiO2 at sea level

150

21

what is a significant A-a gradient

>15mmHg

22

what happens to A-a gradient if patient stops breathing?

stays the same

23

2 diffs between basal and apical alveoli

basal are smaller but diffuse more

24

what is importance of FRC

point of match between lung in and chest out

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