2. Pulmonary Function Tests Flashcards

1
Q

the rate at which the lung deflates (exhales) is a function of what?

A

resistance, and elastic recoil.

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2
Q

elastic recoil is determined by what?

A

properties of the tissue, and the volume to which it is inflated

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3
Q

stiff balloon will empty more or less air in one sec than floppy?

A

more

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4
Q

balloon that is inflated to a higher volume will empty more or less air in one sec than a less-volume balloon?

A

more

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5
Q

low FEV1 comes from what 3 things/

A
  • incr in airway resistance
  • decr in recoil
  • decr in volume
  • any combo of these
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6
Q

diseases in which airway resistance is incr

A

asthma, bronchitis, tracheal tumor, aspiration

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7
Q

diseases in which recoil is decr

A

emphysema

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8
Q

diseases in which lung vol decr

A

restrictive disease

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9
Q

in restrictive disease, is the VC incr or decr?

A

decr

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10
Q

in obstructive disease, is the VC incr or decr?

A

normal or decr

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11
Q

how does pulm fibrosis have opposing effects on the FEV1?

A

elastic recoil incr -> incr FEV1

stiff lungs cannot be inflated very much -> decr FEV1

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12
Q

what measure distinguishes between obstructive and restrictive disease?

A

RATION of FEV1 to FVC.

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13
Q

PFTs in obstructive disease

A

FEV1 decr, FVC normal or decr, ratio decr

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14
Q

PFTs in restrictive disease

A

FEV1 decr, FV decr, ration normal or incr

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15
Q

since we can’t measure FRC or RV with spirometry, how do we measure them?

A

plethysmography (like Inyang did?)

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16
Q

VC + RV = what?

A

TLC.

17
Q

what is FRC?

A

point at which the elastic recoil of lungs exactly balances the recoil of the chest wall

18
Q

what is RV when does it increase?

A

RV = amt of gas left in lungs after max expiratory effort. incr in obstructive disease (air trapping)

19
Q

what is a restrictive ventilatory defect?

A

expansion of the lungs is restricted. reduction in TLC. NOT a reduction in VC. caused by insp muscles being unable to fully inflate the lungs and rib cage.

20
Q

examples of restrictive defect?

A

neuromuscular disease, chest wall problems, pleural disease, loss of lung, interstitial lung disease

21
Q

when is the flow-volume loop most useful?

A

in dx problems with inspiration, exp extra-thoracic airflow obstruction.

22
Q

what affects the diffusing capacity?

A
  • partial pressure gradient of CO between alveolus and blood.
  • total surface area avail for gas exchange
  • hemoglobin
  • thickness of diffusing surface
  • lung vol (if can’t take deep breath, DLCO decr)
23
Q

what happens to diff capacity in smokers?

A

in smokers, there is incr CO in blood, which decr the partial pressure gradient, and decr measured DLCO

24
Q

combination of obstructive pattern and low DLCO suggests what disease?

A

emphysema

25
Q

combination of restrictive pattern, incr ratio, and low DLCO suggests what disease?

A

interstitial lung disease