Alveolar Gas Exchange Flashcards

1
Q

What is the principle function of the lungs and thorax?

A

respiration

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2
Q

What does gas exchange depend on?

A

ventilation, profusion, barriers (air-liquid interface)

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3
Q

The lung gas exchange begins at the level of (blank)

A

respiratory bronchiole

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4
Q

What does fick’s law tells us?

A

diffusion is proportional to surface area and inversely proportional to thickness of surface

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5
Q

In normal lungs is greater at the (Blank) and becomes progressively less towards the (blank).
In supine position this effect is (blank(

A

base
apex
less

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6
Q

Intrapleural pressure is more negative at the (blank) or compared to the bottom

A

top

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7
Q

The change in ventiliation per unit volume is greater at the (blank) than the (blank).

A

base

apex

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8
Q

Blood flow decreases from the (blank) as compared to ventilation which is less step but still decreases from (blank) of lung

A

bottom to the top

bottom to top

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9
Q

In the upright position there is a linear decrease of blood flow from the base to the apex, and (blank) from hilum to outer peripheral lung near pleura.

A

decreases

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10
Q

It is the alteration and abnormalities of the V/q rations that causes what?

A

hypoxia and disease states (ideal is v=q or a v/q=1)

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11
Q

What is the normal range of PaO2 (arterial)

A

70-100

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12
Q

Is PAO2 equal to PaO2?

A

no

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13
Q

decreased PaO2= (blank)

A

hypoxemia

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14
Q

What are basic causes of hypoxemia?

A
decreased PAO2
hypoventilation
reduced FiO2 or low atmospheric pressure
venitlation-perfusion mismatch
diffusion defects
right to left shunt
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15
Q

The higher the altitude the lower the (blank)

A

barometric pressure and PIO2

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16
Q

What is the alveolar gas equation?

A

PAO2=PIO2 or FIO2(Pb-Ph20)-PCO2/R

17
Q

What is a normal P(A-aO2) or A-a gradient or PAO2-PaO2 difference?

A

3-15 on room air

18
Q

How can you have hypoxemia due to hypoventilation?

A

you have decreased PAO2 an PaO2 even with normal A-a difference, just means both are low

19
Q

As you decrease alveolar ventilation, your PACO2 will (blank)

A

increase

20
Q

What causes hypoxemia due to hypoventilation?

A

sedation, neuromuscular diseases, muscle disorders, pharmacologic blockade, high spinal cord lesions, Brainstem infarction/trauma

21
Q

If you have an abnormal A-a gradient what does this tell you?
If you have a normal A-a gradient but low PaO2 and PAO2 what does this tell you?

A

intrinsic lung problem

problems with respiration (breathing messed up)

22
Q

How can you tell a person is brain death?

A

give pure oxygen to 100% point, stop giving it to them and watch to see if they take a breath, their CO2 should increase significantly if they have brain death. You take an ABG and check CO2 levels, if high=brain death

23
Q

(blank) V/Q ratio indicates increased dead space ventilation or increased Vd (there is ventilation to non-perfused lung units->happens with pulmonary emboli)

A

high

24
Q

COPD can do what to your ventilation and profusion? What is your VQ ratio?

A
reduce it (destroy alveolar membrane and induce hypoxic vasoconstriction)
less than 1 and this person is unhealthy
25
Q

The thin and abundant surface area of the NORMAL alveolar-capillary membrane is very well suited for (blank) of gas.The air-liquid interface normally avidly allows (blank). Thickness of RBC can is a barrier for (blank).

A

diffusion
diffusion
diffusion

26
Q

When the alveolar-capillary membrane is compromised you can get what? What will this cause?

A
fluid-pulmonary edema
diffuse pneumonitis
fibrosis (scarring disease)
bronchoalveolar destruction
HYPOXIA
27
Q
What are these:
Right to left shunts:
Intra-cardiac shunts (hole in cardiac chamber)
 -Patent foramen 
 -Atrial septal defects
 -Ventricular septal defects
 -Congenital heart disease
 Extra-cardiac shunts
 -Pulmonary AVMs (arteriovenous malformations)
 -A-V fistulas
A

shunts that cause hypoxemia

28
Q

In a right to left shunt what happens to your V/Q ratio?

A

it approaches zero because your profusion is normal but you are bypassing your alveoli so you are having no ventilation

29
Q

Point is that in a right to left shunt there is minimal effect on (blank) but dramatic effect on (blank)

A

PaCO2

PaO2

30
Q

In a normal healthy person, the physiological shunt is rarely over (blank)

A

4%.

31
Q

What is hypoxemia?

A

Lower than normal PaO2 for a person’s age

Low CaO2

32
Q

What are tools to approach a patient with?

A
hypoxemia
ABG values
PaO2
PaCO2 
Calculated PAO2
P(A-a)O2 difference