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Pulmonary Function Tests > Ch. 3 > Flashcards

Ch. 3 Flashcards

1
Q

What is TLC?

A

volume of gas that remains in the lungs after maximal inspiration

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2
Q

What is TLC used for?

A

To diagnose restriction, air trapping, and hyperinflation

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3
Q

What is RV?

A

The amount of gas that remains in the lungs at the end of maximal expiration

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4
Q

What is FRC?

A

Volume of gas remaining in the lungs after maximal breath

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5
Q

What’s the formula for FRC?

A

FRC = ERV+RV

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6
Q

What is the RV/TLC fraction? What must it be expressed as?

A

Amount of TLC that cannot be exhaled; a percentage

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7
Q

What does an inc. in the RV/TLC fraction indicate?

A

Hyperinflation or air trapping

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8
Q

The RV cannot be measured _______?

A

Directly

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9
Q

What are the 3 methods used for RV?

A

• helium dilution
• nitrogen washout
• body box

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10
Q

What is the He dilution method?

A

• Closed circuit system
• Measures 10% of helium
• Source of O2
• Volume based spirometer
• He analyzer (must be calibrated)
• CO2 & H2O absorber

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11
Q

What does He dilution measure?

A

FRC and estimates lung volumes

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12
Q

The helium is _______ until _______ is reached?

A

Diluted; equilibrium

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13
Q

Helium ______Vt & TLC

A

Underestimates

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14
Q

What is the nitrogen washout?

A

• open circuit system
• Pneumotachometer
• nitrogen analyzers & 100% O2
• pt is given 100% O2
• pt continues to rebreathe 100% O2

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15
Q

What does an inc in N2 mean?

A

You have leak

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16
Q

What does the N2 washout measure?

A

Flow rate of gases during breathing

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17
Q

How long must you wait before you can retest for N2 washout?

A

15 min

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18
Q

How long does the test take in healthy lungs?

A

3-4 (up to 7-8) mins

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19
Q

What does the body box measure?

A

• FRC & thoracic gas volume
• Gas in thorax

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20
Q

What is the body box based on?

A

Boyle’s law

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21
Q

What is Boyle’s law?

A

A volume of gas varies inversely w/pressure when temp is constant

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22
Q

What are the 2 types of body boxes?

A

• flow based
• constant volume (pressure type)

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23
Q

Changes in _______ pressure is measured at the _____ when shutter is closed?

A

Alveolar; mouth

24
Q

Test must be _____ & ______ .

A

Acceptable; replicable

25
Q

What are some examples of drift or artifact?

A

Cough or leaks

26
Q

How do you know if calibration is done correctly?

A

Tracing will go off

27
Q

What is the frequency for acceptable tests?

A

0.5-1

28
Q

How many test do you need within acceptable parameters?

A

3

29
Q

FRC must be within _____ %

A

15

30
Q

What is the most accurate test for measuring lung volumes?

A

Body box

31
Q

____ can also be monitored?

A

Raw

32
Q

Body box shows what?

A

Instant changes throughout testing

33
Q

Measurements are not affected by _____ effort?

A

Pt

34
Q

Comparing the FRC is optimal for assessing ______ _______ ?

A

Air trapping

35
Q

Single breath He dilution is?

A

• closed circuit
• calculated as part of DLCO

36
Q

What does Single breath He dilution measure?

A

TLC

37
Q

Single breath N2 washout is?

A

An open circuit

38
Q

What are the 4 phases of volume for N2 washout?

A

• lung volumes
• closing capacity
• closing volumes
• anatomic dead space (gas that does not participate in gas exchange).

39
Q

How many phases are there of the N2 washout curve?

A

Phase 1
Phase 2
Phase 3
Phase 4

40
Q

What is phase 1 of the N2 washout curve?

A

Upper airway gas from the anatomic dead space (V danat) consisting of 100% O2

41
Q

What is phase 2 of N2 washout?

A

Mixed dead space gas in which the relative concentration of O2 and N2 change abruptly as the V danat volume is expired

42
Q

What is phase 3 of N2 washout?

A

A plateau caused by the exhalation of alveolar gas in which relative O2 and N2 concentrations change slowly and evenly.

43
Q

What is phase 4 of the N2 washout?

A

An abrupt increase in the concentration of N2 that continues until RV is reached

44
Q

An increase in the stage of phase 3 indicates what?

A

Uneven distribution

45
Q

Deceased TLC =

A

Suspected restriction

46
Q

Increased TLC =

A

Suspected obstruction

47
Q

Increased FRC =

A

Suspected hyperinflation or air trapping

48
Q

Increased RV w/ normal TLC =

A

Air trapping

49
Q

Increased RV w/ inc.TLC =

A

Hyperinflation

50
Q

Inc. RV w/normal TLC & Inc RV w/ inc. TLC are indicators of what?

A

Obstruction

51
Q

⬇️ FRC, RV, & TLC are all indicators of what?

A

Restriction

52
Q

What makes up IC?

A

IC=IRV+Vt

53
Q

What make up VC?

A

VC=IRV+Vt+ERV

54
Q

What is the TLC made up of?

A

TLC = IRC+VC+Vt+FRC+ERV+RV+IC
Everything

55
Q

Label this pic

A
  1. IRV
  2. VC
  3. Vt
  4. FRC
  5. ERV
  6. RV
  7. IC
  8. VC
  9. ERV
  10. RV
  11. FRC
  12. Vt
  13. IRV
  14. TLC

Pulmonary Function Tests (8 decks)

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