Ch. 16 PFTs (Test 2) Flashcards

1
Q

Define Tidal Volume

A

The volume of air (usually in milliliters) that is inhaled or exhaled during a normal breath

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2
Q

The exhaled Vt is usually measured with a _____________ at the bedside or by _________________

A

respirometer ;
spirometry

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3
Q

Vt is decreased or normal in ________ disease

A

restrictive

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4
Q

Vt is increased or normal in obstructive disease

A

know

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5
Q

What is a normal value for Vt

A

400 to 700 mL ( 3 to 4 mL/lb of IBW or 5 to 6 mL/kg)

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6
Q

Is the maximum volume of air that can be inspired after a normal inspiration

A

Inspiratory reserve volume (IRV)

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7
Q

IRV normally is not measured during simple spirometry, but if it is, it should be measured from a slow vital capacity

A

KNOW

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8
Q

Normal value for IRV

A

3000 mL

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9
Q

IRV can be both

A

obstructive and restrictive diseases

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10
Q

Expiratory reserve volume (ERV) is the volume of air after a

A

normal expiration

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11
Q

A normal ERV value is

A

1000 mL and 20% to 25% of the VC

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12
Q

The volume of air left in the lungs after a maximal expiration

A

Residual volume (RV)

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13
Q

RV=

A

FRC-ERV

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14
Q

RV is ___________ in obstructive diseases and ___________ in restrictive diseases

A

increased;
decreased

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15
Q

A normal RV is

A

1500 mL

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16
Q

This test is the amount of air left in the lungs after a normal expiration

A

Functional lung capacity (FRC)

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17
Q

FRC=

A

ERV+RV

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18
Q

How is FRC measured (3)

A
  • Closed circuit helium dilution
  • Open circuit nitogen washout
  • Body plethysmography
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19
Q

IC is the maximun amount of air that can be inspired after a normal expiration

A

know

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20
Q

IC=

A

Vt+ IRV

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21
Q

A normal value for IC is

A

3500 mL (75% to 85% of the VC)

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22
Q

The maximum amount of air that can be exhaled after a maximum inspiration

A

Vital Capacity (VC)

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23
Q

VC=

A

Vt+IRV+ERV

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24
Q

A normal VC is

A

4800 mL

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25
Q

A decreased VC may be the result of (6)

A
  • pneumonia
  • atelectasis
  • pulmonary edema
  • pulmonary fibrosis
  • kyphoscoliosis
  • lung cancer.
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26
Q

Forced vital capacity (FVC) is the maximum amount of air that can beexhaled as

A

quickly and forcefully as possible after a maximum inspiration

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27
Q

Total lung capacity (TLC) is the amount of air remaining in the lungs at the end of a maximal inspiration

A

know

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28
Q

TLC=

A

FRC +IC
or
VC+ RV

29
Q

A normal TLC is

A

6000 mL

30
Q

TLC decreases as a result of

A
  • atelectasis
  • pulmonary edema
  • consolidation
31
Q

What disease process does TLC increase in?

A

Emphysema

32
Q

Vt

A

500 ml

33
Q

ERV

A

1000 ml

34
Q

RV

A

1500 ml

35
Q

IRV

A

3000 ml

36
Q

FRC

A

2500 ml

37
Q

IC

A

3500 ml

38
Q

VC

A

4500 ml

39
Q

TLC

A

6000 ml

40
Q

If FEV1/ FVC < 70 it is considered what

A

obstructed disease

41
Q

Decreased FVC is considered

A

restrictive disease

42
Q

Severity of obstruction (by interpretation of FEV1)
Mild:

A

70% to 74% of predicted value

43
Q

Severity of obstruction (by interpretation of FEV1):
Moderate

A

60% to 69% of predicted value

44
Q

Severity of obstruction (by interpretation of FEV1): Moderately severe

A

50% to 59% of predicted value

45
Q

Severity of obstruction (by interpretation of FEV1): Severe

A

35% to 49% of predicted value

46
Q

Severity of obstruction (by interpretation of FEV1): Very severe

A

<35% of predicted value

47
Q

Before-and-After Bronchodilator Studies

A

Reversibility of obstructed airways and improved flow rates are considered significant if increases in flow studies are at least 12%.

48
Q

On the graph obstructive looks like a boot

Restrictive looks long an tall

A

KNOW

49
Q

Predicted values are determined from (HGARW)

A
  1. Age
  2. Gender
  3. Height
  4. Ideal body weight
  5. Race
50
Q

If FRC and RV is elevated then it is an ______________ disease

A

obstructive

51
Q

Following are the results of a patient’s spirometry test before and after bronchodilator therapy.

Before
FEV1. 32% of predicted
FVC. 38% of predicted
FEV1/FVC 50%

After
FEV1 53% of predicted
FVC 66% of predicted
FEV1/FVC 64%

Which of the following is the correct interpretation of these results?

A. Mild restrictive disease with significant bronchodilator response

B. Severe obstructive disease with significant bronchodilator response

C. Severe restrictive disease with no significant bronchodilator response

D. Severe obstructive disease with no significant bronchodilator response

A

Severe obstructive disease with significant bronchodilator response

52
Q

To best determine an asthmatic’s response to a bronchodilator, which of the following tests should be performed before and after the use of a bronchodilator?

A. VT
B. VE
C. Peak flow
D. MIP

A

Peak flow

An increase in the patient’s peak expiratory flow rate after being administered a bronchodilator is a good indicator of whether the airways responded well. Generally, a 12% or more improvement indicates a significant response to the bronchodilator.

53
Q

The FEF25-75 is measured using which of the following pulmonary function tests?

A. FRC
B. FVC
C. TLC
D. MVV

A

FVC

The forced expiratory flow (FEF25–75) is measured during the FVC maneuver as the patient takes the deepest possible breath and exhales the volume as fast and forcefully as possible. Values are decreased in obstructive disease. A normal value is 4 to 5 L/s.

54
Q

In which of the following lung conditions would the functional residual capacity (FRC) be increased?
1. Emphysema
2. Cystic fibrosis
3. Pneumonia

A. 1 only
B. 1 and 2 only
C. 1 and 3 only
D.2 and 3only

A

1 and 2

FRC is the amount of air left in the lungs after a normal exhalation. This capacity increases in any condition in which air-trapping occurs, such as in emphysema and cystic fibrosis.

55
Q

Which of the following values would you expect to be decreased in a patient with emphysema?

A. FEV1/FVC
B. TLC
C. FRC
D. RV

A

FEV1/FVC

The airways of emphysema patients tend to collapse prematurely, obstructing flow during exhalation and reducing exhaled volume. An FEV1/FVC ratio of less than 70% indicates obstructive lung disease. The collapsing airways also trap air in the lungs; therefore more air remains in the lungs after exhaling and is evidenced by increases in TLC, FRC, and RV.

56
Q

The respiratory therapist explains to the patient at his bedside to take the deepest breath he can and exhale completely as fast and forcefully as possible. From this instruction, the therapist will be able to measure the patient’s:

A. FVC
B. FRC
C.MVV
D. IC

A

FVC

The therapist’s instruction to the patient in this question describes an FVC maneuver. Normal value is 65 to 75 mL/kg.

57
Q

What is the minimum percent increase in expiratory flow following a before-and-after bronchodilator study that indicates significant improvement?

A. 8%
B. 12%
C. 18%
D. 20%

A

12%

A 12% improvement in a before-and-after bronchodilator study indicates that significant improvement was achieved with the bronchodilator.

58
Q

Which of the following pulmonary function tests would best determine the patient’s ability to cough?

A. VT
B. Alveolar VE
C. FRC
D. MIP

A

MIP

MIP is the maximum amount of negative pressure a patient can generate during inspiration. It determines how deep a breath the patient can take, which is essential for an adequate cough. Normal MIP is -50 to -100 cm H2O. An MIP of greater than -20 cm H2O indicates that the patient has not produced enough negative pressure to cough adequately and ventilator assistance is necessary.

59
Q

To evaluate the distribution of ventilation to perfusion with a V/Q scan, instruct the patient to inhale which of the following substances?

A. Helium
B. CO
C. Xenon
D. Argon

A

Xenon

Xenon is a radioactive isotope that the patient inhales. Photoscintigrams are used to determine how well the xenon was distributed in the lung. Photoscintigraphy evaluates the relationship of the distribution of ventilation to pulmonary perfusion

60
Q

Maximal expiratory pressure (MEP)

A
  1. An aneroid manometer is attached to the patient’s ET tube, and the patient is instructed to inhale as deeply as possible and exhale forcefully and completely.
61
Q

A normal MEP is

A

90 to 100 cm H2O

62
Q

Patients unable to generate an MEP of at least 40 cm H2O of pressure are not able to maintain adequate spontaneous ventilation or secretion clearance, which makes mechanical ventilation necessary.

A

KNOW

63
Q

NO is produced as a gas by macrophages,eosinophils, and endothelial and epithelial cells.It is present in exhaled air.

A

KNOW

64
Q

NO increases when airway inflammation occurs
and is a valuable method to both diagnose andmanage asthma

A

KNOW

65
Q

What is a Wright Respirometer ( Vane respirometer?

A

A handheld device that is frequently used at the pt’s bedside to measure VC, Vt, and VE

66
Q

Wright Respirometer may be placed in-line to vent circuits to measure the pt’s exhaled volume and should be placed on the

A

expiratory side of the circuit as close to the pt as possible

67
Q

Bedside (Portable) Spirometers- These flow-sensing spirometers can interface with either a laptop computer or a personal computer. Some types utilize microprocessors that are as small as a calculator. With the use of the appropriate software, spirometry can be performed at the bedside.

A

KNOW

68
Q

Bedside (Portable) Spirometers can measure

A
  • FVC
  • FEV1
  • FEV/FVC ratio