Airway closure Flashcards

1
Q

What is the physiological basis of airway closure?

A

Pressure drops as fluid flows through a tube

P1 > P2

AKA- As gas flows through a tube, pressure falls. In the airway, pressure decreases as gas flows along the bronchioles.

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2
Q

Forces keeping airway open during inspiration and forces causing closure during forced expiration:

During forced expiration intrapleural pressure becomes what?

A

Positive

30 cm H20 in picture

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3
Q

Forces keeping airway open during inspiration and forces causing closure during forced expiration:

the high intrapleural pressure (30 cm H2O) is transmitted to the what?

A

Alveoli

38 cm H2O in this picture

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4
Q

Forces keeping airway open during inspiration and forces causing closure during forced expiration:

As the air flows along the airway, the pressure in the airway begins to what?

A

fall

(remamber as fluid or gas flows through a tube, pressure falls)

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5
Q

Forces keeping airway open during inspiration and forces causing closure during forced expiration:

At some point in the airway the intrapleural pressure sufficiently exceeds airway pressure, and the airway does what?

A

closes

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6
Q

Forces keeping airway open during inspiration and forces causing closure during forced expiration:

in the diagram the airway closes when the pressure falls to 19cmH2O

A
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7
Q

why does the trachea not close then?

A

b/c it has rings

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8
Q

what part of the airway is suceptable ro collapsing

A

bronchioles to alveoli

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9
Q

why do the mainstems not collapse?

A

b/c they have rings also

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10
Q

Closing volume (CV) and Closing Capacity (CC):

at some point during forced expiration, airways begin to close. The volume that can subsequently be exhaled is called the

A

closing volume

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11
Q

Closing volume (CV) and Closing Capacity (CC):

What makes up the closing capacity

A

the closing capacity is the closing volume plus the residual volume

CC = CV + RV

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12
Q

Closing volume (CV) and Closing Capacity (CC):

the CV and CC are measures how?

A

nitrogen washout test

and

helium dilution method

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13
Q

Closing volume (CV) and Closing Capacity (CC):

what happens if your CC is higher than your FRC?

A

you have no reserve (no FRC)

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14
Q

Closing volume (CV) and Closing Capacity (CC):

what typw of pt may have a CC higher than FRC

A

Elderly

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15
Q

Closing volume (CV) and Closing Capacity (CC):

since older peoples CC exceeds their FRC what does this mean in relation to thir airway closure?

A

they close without forced expiration

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16
Q

Young VS Eldery CC

A
17
Q

Fast Facts about Airway closure:

Airway closure in the yooung healthy individual during expiration at low lung volumes; expiration must be forced to acheive lung volumes where airway closure occurs

A

just read

18
Q

Fast Facts about Airway closure:

In young healthy individuals airway closure (CV) occurs at a lung volume equal to about __% of VC

A

10%

19
Q

Fast Facts about Airway closure:

the volume at which airway closure occurs _____ with age

A

increases

20
Q

Fast Facts about Airway closure:

CV are increased with what type of Airway dz

A

Obstructive

(asthma/COPD/ bronchitis)

21
Q

Fast Facts about Airway closure:

what are other things that can increase closing volumes

A

Smoking

bronchospasm

Airway secretions

Fluid retention

Anesthesia/surgery

22
Q

does pulmonary compliance increase or decrease with age?

A

increases

23
Q

How does FRC change w/ age?

A

since the lung does not recoil inward with as much force, FRC INCREASES slightly with age ~10%

24
Q

does chest wall compliance increase or decrease with age?

A

decreases

25
Q

FRC = what

A

FRC = RV + ERV

26
Q

VC = what

A

VC = ERV + TV + IRV

27
Q

what happens to FRC w/ obstructive dz?

A

increased

28
Q

what happens to VC with obstructive Dz

A

decreased

29
Q

what happens to TLC with obstructive dz

A

increase

30
Q

what happens to FRC, VC, and TLC with restricted dz

A

all decreased