Lecture 14: Pulmonary Function Tests (Exam III) Flashcards

1
Q

Where on the PFT graph below does N2 start to show up on our nitrogen meter?

A
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2
Q

What is the partial pressure of nitrogen in room air?

A

560mmHg

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3
Q

What test is depicted in the graph below?

A

Nitrogen washout test

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4
Q

What should a normal nitrogen concentration in the atmosphere be?

A

75 - 80 %

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5
Q

What percentage nitrogen should a healthy 20 y/o have at 3 minutes into a nitrogen washout test?

A

2.5% in 3 min

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6
Q

What is a normal reading on a nitrogen washout test?

A

2.5% in less than 7 min

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7
Q

What is an abnormal reading on a nitrogen washout test?

A

2.5% in greater than 7 min

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8
Q

Which of the two nitrogen washout tests below displays an abnormal and uneven air distribution?

A

Right graph

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9
Q

How might VD be estimated from the graph below?

A

VD = phase I + ½(phase II)

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10
Q

What lung volume comprises the entirety of phase I in the figure below?

A

VD (Anatomical Dead Space)

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11
Q

What lung volume(s) comprise phase II in the figure below?

A

Phase II = Transitional Phase = VD + VA air

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12
Q

Where is air coming from in phase III in the figure below?
What is the nitrogen concentration of this air?

A
  • All areas of the lungs
  • [N₂] ≈ 20%
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13
Q

What phase in a closing capacity/volume test is the longest for healthy people?

A

Phase III

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14
Q

What causes the sharp upswing noted in Phase IV in the figure below?

A

Lung base small airways start to collapse so [N₂] starts to increase.

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15
Q

In what area of the graph below will we notice excessive compliance?

A
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16
Q

At what lung volume does inspiration start when conducting a closing volume/capacity test?

A

RV

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17
Q

What is indicated by 1 in the figure below?

A

Closing Volume

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18
Q

What is indicated by 2 in the figure below?

A

Residual Volume

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19
Q

What is indicated by 3 in the figure below?

A

Closing Capacity

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20
Q

What is indicated by 4 in the figure below?

A

Vital Capacity

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21
Q

What lung capacity changes the most with age?

A

Closing Capacity

22
Q

At what age will closing capacity equate to functional residual capacity?
What does this mean?

A
  • Age: 50
  • CC = FRC means that the airways of the lung base collapse in normal respiration.
23
Q

Which lung capacities decrease with age?

A
  • IC
  • VC
  • ERV
24
Q

Which lung capacities increase with age?

A
  • FRC
  • RV
  • CC
25
Q

Where would closing volume be located on the graph below?

A
26
Q

Why are small airways more prone to collapse as we age?

A

Loss of traction

27
Q

If a full inspiration of FiO₂ 100% were taken from this lung in the graph below, where would [N₂] be more diluted?

A

Base of the lung due to having a lower starting volume of 20%.

someone check this one, the O₂ should theoretically go to the apex first since we’re taking an inspiration from RV, right?

28
Q

At what stage of the respiratory cycle would you expect a healthy person to have the best possible traction?

A

2 seconds into inspiration and right before expiration when the lungs are fullest.

Best traction at higher lung volumes.

29
Q

Does traction increase or decrease as we get closer to RV?

A

Traction decreases

30
Q

How can vital capacity be determined from the graph below?

A

TLC - RV

31
Q

Would effort-dependent expiration occur at higher or lower lung volumes?

A

Effort-dependent expiration = TLC and higher lung volumes

32
Q

Would effort-independent expiration occur at higher or lower lung volumes?

A

Effort-independent expiration = RV and lower lung volumes

33
Q

In a healthy patient, what percentage of vital capacity expiration should occur in the first second of expiration?

A

80% of VC expired in 1st second of expiration.

34
Q

What is the forced expiratory flow rate in someone young and healthy?

A

10 L/s

35
Q

What sort of pathology would you expect from the peak expiratory curve below? Why?

A
  • Emphysema
  • Loss of PER causes leftward shift of effort independent expiratory flow.
36
Q

What sort of pathology is indicated by figure 1 below?

A

Obstructive disease (Emphysema)

37
Q

What sort of pathology is indicated by figure 2 below?

A

No Pathology, normal expiratory function curve.

38
Q

What sort of pathology is indicated by figure 3 below?

A

Restrictive disease (Fibrosis)

39
Q

What causes the pathology noted by 1 in the figure below?

A

Emphysema → Loss of PER

40
Q

Which of the following curves would have the greatest degree of effort-independent expiratory flow?

A
  1. Emphysema
41
Q

What are the peak expiratory flow rates of each of the curves below?

A
  1. 8 L/s
  2. 13 L/s
  3. 10 L/s
42
Q

What are vital capacities of each of the curves below?

A
  1. VC ≈ 3.75L (8.5 - 4.75)
  2. VC ≈ 4.5L (6 - 1)
  3. VC ≈ 3L (4.1 - 1.1)
43
Q

Does a forced expiration or a passive expiration present more of a risk for small airway collapse?

A

Forced Expiration

44
Q

When would small airway collapse be more likely?

A

COPD/Emphysema

45
Q

Loss of what capability would increase the risk of small airway collapse?

A

PER

46
Q

How does pursed-lip breathing prevent airway collapse?

A

Pursed-lip breathing will restrict outflow and increase airway pressures

Airway pressures > PIP = no collapse

47
Q

What causes the increased pressures seen in the rightmost figure below?

A

Contraction of intercostal muscles, accessory muscles, and abdominal muscles.

48
Q

Loss of _____ will result in more collapsible airways.

A

PER (Traction)

49
Q

The flow-volume curve below is indicative of what?

A

Fixed Obstruction (ex. ETT)

50
Q

The flow-volume curve below is indicative of what?

A

Variable extra-thoracic obstruction (ex. scar tissue, paralyzed vocal cords)

51
Q

The flow-volume curve below is indicative of what?

A

Variable intra-thoracic obstruction (ex. small airway collapse, traction loss on expiration)

52
Q

What does the dotted line in the graph below indicate?

A

Increased volume from emphysema allows some air escape at the beginning of expiration when lungs are fullest.