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Flashcards in Resp - Ventilation Deck (15):
1

Henry's law

amt of a gas that dissolves into a fluid is proportional to:
solubility
temp
partial P

2

Dalton's law

total P of a gas mixture is equal to sum of Ps that each gas exerts independently
(Patm = PO2 + PN2...)

3

effects of humidity on O2

dilute PP
no change in O2, just partial P

4

total ventilation

VE = VT x f
(total ventilation = tidal volume x respiratory rate)
VT more important

5

types of dead space

anatomical (conducting airways)
alveolar (in unhealthy)
physiological = anatomical + alveolar
(healthy physiological = anatomical)

6

alveolar ventilation

VA = (*VT - VD) x f
alveolar ventilation = (tidal V - anatomic dead space) x resp rate
VT most imporant

7

alternate equation to VA

VA = VECO2 x 0.863/ PACO2
show how effecctively reducing CO2

8

CO2 alveolar P eq

PACO2 = VECO2 x 0.863/VA
PACO2 can be substituted by PaCO2

9

hypo/hyperventilation and CO2

hyperventilate --> PaCO2 down
hypoventilate --> PaCO2 up

10

conclusions drawn from high PaCO2

not enough ventilation (CNS, muscle weak)
too much ventilation ending up as dead space (COPD, rapid shallow breaths)

11

alveolar gas equation

PAO2 = PIO2 - PACO2/R
R usually 0.8

12

respiratory quotient

R
usually 0.8
ratio of VCO2/VO2
CO2 produced/O2 taken up

13

A-a gradient

for healthy person, PAO2 ~ PaO2
diff is A-a gradient

14

reason for A-a gradient

50% due to regional diff in V/Q (high at apex)
50% due to anatomic shunt (broch veins drain into pulm veins)

15

why is PACO2 = PaCO2

high diffusibility (very soluble)