Pulmonary Function Tests

Question 1

Assessing the functional status of the lungs as it relates to:
5

Answer 1

1. How much air volume can be moved in and out of the lungs
2. How fast the air in the lungs can be moved in and out
3. How stiff the lungs and chest wall are - a question about compliance
4. The diffusion characteristics of the membrane through which the gas moves (determined by special tests)
5. Measurement of how the lungs have responded to treatment

Question 2

Indications for PFT?

5

Answer 2

1. Screening for lung disease in patients with symptoms
2. Following the progression of pulmonary disease - restrictive or obstructive
3. Evaluating the effectiveness of therapeutic intervention
4. Evaluating the patient prior to certain types of surgery:
5. Objective assessment of impairment or disability

Question 3

Evaluating the patient prior to certain types of surgery is an indication for PFTs. What would this help us with? 4

What kind of patients would benefit from this evaluation?? 3

Answer 3

1. risk for postoperative respiratory complications
   Reflects the patient’s ability to
2. take a deep breath,
3. to cough, and
4. to clear the airways of excess secretions

COPD, CHF, Do they have enough pulomnary reserve to get them off the ventilator?

Question 4

Types of Pulmonary Function Tests?

5

Answer 4

Spirometry

Peak flow

Measurement of lung volumes

Quantification of diffusion capacity

Oxygen uptake (VO2)—exercise capacity

Question 5

What does spirometry measure?

2

Answer 5

1. Forced expiratory volume in one second (FEV1)
2. Forced vital capacity—(FVC)

Most readily available and most useful PFT
$1,500 – $2,500

Question 6

Definition of spirometry?

What does it assess?

Answer 6

Spirometry with flow volume loops assesses the mechanical properties of the respiratory system by measuring expiratory volumes and flow rates
(how much they can inhale and exhale and how fast they can do it)

Question 7

Flow volume loops provide what?

How is the chart plotted?

Answer 7

a graphic illustration of a patient’s spirometric efforts

flow against volume

Question 8

The normal volume time curve for spirometry is shaped how?

The maximum volume attained represents what?

while the volume attained after one second represents what?

Answer 8

has a rapid upslope and approaches a plateau soon after exhalation

the forced vital capacity (FVC),

the forced expiratory volume (FEV1)

Question 9

Variables that might affect a spirometry test?

4

Answer 9

Age
Gender
Race
Body height and size

Question 10

Why would age change the PFT?
2

Why would gender affact the PFT?
2

How does race affect PFTs?

Answer 10

1. The natural elasticity of the lungs decreases
2. This translates into smaller and smaller lung volumes and capacities as we age
3. Usually the lung volumes and capacities of males are larger than the lung volumes and capacities of females.
4. Even when males and females are matched for height and weight, males have larger lungs than females.
5. Blacks, Hispanics and Native Americans have different PFT results compared to Caucasians

Question 11

If person becomes too obese how will this affect the PFT?

Answer 11

the abdominal mass prevents the diaphragm from descending as far as it could and the PFT results will demonstrate a smaller measured PFT outcome

Question 12

What are some examples of obstructive disorders?

7

Answer 12

1. Asthma
2. Bronchitis
3. Excessive mucus plugging
4. foreign object inhalation
5. invasive tumors
6. COPD
7. Emphysema

Question 13

1. “Restriction” in lung disorders always means a what?
2. This term can be applied with confidence to patients whose total lung capacity has been what?
3. What is total lung capacity?
4. Why cant TLC be measured by spirometry?
5. TLC is the summation of what?

Answer 13

1. decrease in lung volumes
2. measured and found to be significantly reduced
3. Total lung capacity (TLC) is the volume of air in the lungs when the patient has taken a full inspiration.
4. because air remains in the lungs at the end of a maximal exhalation - i.e. the residual volume or RV
5. The TLC is therefore the summation of FVC + RV

Question 14

What are the ways you can measure TLC?

4

Answer 14

1. Helium dilution
2. Nitrogen washout
3. Body plethysmography (gold standard)
4. Chest radiograph or HRCT measurements

Question 15

Neuromuscular Restrictive lung Disorders

6

Answer 15

1. Generalized Weakness – malnutrition
2. Paralysis of the diaphragm
3. Myasthenia Gravis
4. Muscular Dystrophy
5. Poliomyelitis
6. Amyotrophic Lateral Sclerosis

Question 16

Intrinsic Restrictive Lung Disorders?

4

Answer 16

1. Sarcoidosis
2. Tuberculosis
3. Pneumonectomy
4. Pneumonia

Question 17

Extrinsic Restrictive
Lung Disorders
8

Answer 17

1. Scoliosis, Kyphosis
2. Ankylosing Spondylitis
3. Pleural Effusion
4. Pregnancy
5. Gross Obesity
6. Tumors
7. Ascites
8. Pain on inspiration
   - -Pleurisy, rib fractures

Question 18

What is FEV1?

Answer 18

forced expiratory volume in1sec:
the volume of air that is forcefully exhaled in one second
It is 75% of FVC

Question 19

What is FVC?

Answer 19

forced vital capacity
the volume of air that can be maximally forcefully exhaled
NOT the TLC

Question 20

What is the FEF 25-75%?

What does it measure?

Answer 20

the average forced expiratory flow during the mid (25 - 75%) portion of the FVC

measures of the flow rate in liters per second of the middle half of a FVC test

Question 21

Why do we want to look at the middle half of the forced expiratory flow?
2

Answer 21

The first quarter is effected by the patients effort in overcoming the inertial forces which resist thoracic wall expansion

The last quarter is polluted by the pts dimishing physical effort in instigation of bronchospasm during forced expiration and the breathlessness associated with the terminal completion of a FVC test.

Question 22

What is FEF 25%-75% a senstive test for?

Answer 22

obstructive airway disease

Question 23

What is PEFR?

What does it measure?

Answer 23

The peak expiratory flow rate (PEFR) during expiration

Peak Expiratory Flow Rate (PEFR) is a measure of the highest expiratory flow rate during the PFT test

Question 24

What is PEFR best used for?

Answer 24

Patients with a low PEFR would have to be further evaluated for obstructive pathologies

A useful measure to see if treatment is improving obstructive disease (like bronchoconstriction in asthma)

Question 25

What is TLC?

Answer 25

Total lung capacity (TLC): The volume in lungs at maximum inspiration

Question 26

What is VC?

Answer 26

Vital capacity (VC): The maximum volume expired after a maximum inspiration

Question 27

What is TV?

Answer 27

Tidal volume (TV): The volume inspired and expired during normal breathing

Question 28

What is RV?

Answer 28

Residual volume (RV): The volume left in the lungs after maximal expiration

Question 29

What can lung volumes only be measured with?

Answer 29

body plethysmography (body box)

Question 30

Values for FVC and FEV1 that are over ____ of predicted are defined as within the normal range?

Answer 30

80%

Question 31

A normal flow volume loop has a ____ peak expiratory flow rate with a _____ decline in flow back to zero?

Answer 31

rapid gradual

Question 32

How does the inspiratory portion of the loop look like of the flow axis?

Answer 32

The inspiratory portion of the loop is a deep curve plotted on the negative portion of the flow axis

Question 33

Criteria for acceptability of a properly done PFT include? | 4

Answer 33

1. Lack of artifact induced by coughing, glottic closure, or equipment problems (primarily leak) 2. Satisfactory start to the test without hesitation 3. Satisfactory exhalation with six seconds of smooth continuous exhalation and/or 4. a plateau in the volume time curve of at least one second, or a reasonable duration

Question 34

What is the primary abnormality detected by spirometry?

Answer 34

airway obstruction

Question 35

Name three obstructive lung diseases? How is the FEV1 affected? How does this affect the FEV1/FVC?

Answer 35

1. COPD, 2. asthma, or 3. chronic bronchitis: the FEV1 is reduced disproportionately more than the FVC resulting in an FEV1/FVC ratio less than 70%.

Question 36

How does obstructive disease change the appearance of the flow volume curve? 3

Answer 36

1. There is a rapid peak expiratory flow 2. The curve descends more quickly than normal 3. It takes on a concave shape (reflected by the marked decrease in the FEF25-75)

Question 37

What is a Bronchoprovocation challenge used in? | 3

Answer 37

1. Patient who has symptoms of asthma, normal PFTs and no response to bronchodilator therapy 2. Patient who experiences symptoms not usually associated with asthma 3. Individuals who require screening tests for asthma such as scuba divers, military personnel or others where bronchospasm would pose a risk

Question 38

Patients who CANNOT be Bronchoprovocation challenged? | 6

Answer 38

1. Those who have unstable cardiac disease 2. Heart attack in the last 3 months 3. Stroke in the last three months 4. Uncontrolled hypertension 5. Those with significant bronchospasm already present 6. Pregnancy or nursing mother

Question 39

Describe the Methodology behind a Bronchoprovocation challenge? 4

Answer 39

1. Adequate spirometry—baseline 2. Administer the agent—methacholine via nebulizer: at decreasing dilutions of the agent 3. Repeat spirometry—30 and 90 seconds after 4. Positive test is a decrease of 20% in FEV1

Question 40

HOw would we determine the reversibility of an airway obstruction? 3

Answer 40

1. Pre- and post- bronchodilator spirometry (example of a bronchodilator?) 2. Used to determine if there is reversible airway obstruction 3. Used to determine if an intervention is helpful in treatment

Question 41

With the bronchodilator test, when is it said that the pt has reversible airway obstruction?

Answer 41

If two out of three measurements (FVC, FEV1 and FEF25% - 75%) improve, then it can be said that the patient has a reversible airway obstruction that is responsive to medication

Question 42

What values are reduced in restrictive lung disease? 2 HOw does this affect the FEV1/FVC ratio?

Answer 42

both the FEV1 and FVC are reduced proportionately by affecting both the FEV1 and the FVC, restrictive lung disease presents with a normal or increased FEV1/FVC ratio

Question 43

``` Obstructive: FEV1? FVC? Ratio? What kind of reduction? ``` ``` Restrictive: FEV1? FVC? Ratio? What kind of reduction? ```

Answer 43

``` FEV1 - down FVC - nl or down Ratio – down Disproportionate reduction in FEV1 to FVC ``` ``` FEV1 - down FVC - down Ratio - nl or up Proportionate reduction in FEV1 To FVC ```

Question 44

Criteria for Obstructive Disease ? | 4

Answer 44

1. Air in the lungs will not be readily exhaled because of physical obstruction 2. There will be airway collapse during exhalation (loss of elastic recoil of the lungs) 3. In obstructive diseases, the lung's air volume will be more slowly expelled 4. It will be a smaller volume over the time course of the FVC test

Question 45

Criteria for Restrictive Disease? | 3

Answer 45

1. Patients with restrictive lung disease, the FEV1 will be lower than predicted normal values and so will the FVC 2. Both of these values may equally be effected in restrictive disease, the FEV1/FEV may well be calculated to be between 85% - 100% of normal 3. In restrictive disease look closely at FEV1/FVC when FEV1 and FVC are low and if the FEV1/FVC is 85% or greater, then you should suspect the patient has a restrictive pathology.

Question 46

Criteria for a Mixed Disorder? | 4

Answer 46

1. If the patient demonstrates a reduced FVC, the patient may repeat the test after inhaling a bronchodilator 2. The post-bronchodilator test often shows an improved FVC 3. This simple clinical test strongly suggests that the FVC was low due to obstructive phenomenon 4. If the FVC did not change, it suggests the FVC was possibly low due to restrictive pathologies

Question 47

Grading the severity of disease American Thoracic Society Criteria for FEV1 % of predicted: 5

Answer 47

1. Mild: > 70 2. Moderate: 60-69 3. Moderately Severe: 50-59 4. Severe: 35-49 5. Very Severe: less than 35

Question 48

A Systematic Way To Interpretation of PFTs | 5

Answer 48

Step 1 - Determine the FEV1/FVC ratio (if (if less than 70% then abnormal) Step 2 – Determine if the FVC (if less than 80% of predicted then abnormal) Step 3 - a) If both FVC and FEV1 are normal, then the patient has a normal PFT test (do they need a challenge test?) b) if either are abnormal then do a bronchodilator challenge. Is there are change of at least 12% or 200mL in the FEV1 or FVC? Step 4 - If FVC and/or FEV1 are low, then the presence of disease is highly likely Step 5 - If Step 4 indicates that there is disease, then you need to go to the % predicted for FEV1/FVC

Question 49

If the % predicted for FEV1/FVC is normal or increased then the patient has what? If the % predicted for FEV1/FVC is 69% or lower, then the patient has what?

Answer 49

restrictive lung disease (next step is to order DLCO) an obstructive lung disease

Question 50

Diffusion Capacity (DLCO) It is a useful test for: 6

Answer 50

1. Determining the degree of emphysema in smokers 2. Differentiating chronic bronchitis from emphysema in smokers 3. In restrictive disease differentiating interstitial lung disease from external restrictive etiologies of disease 4. Recurrent PEs 5. Pulmonary HTN 6. Disability measurement

Question 51

Methodlology for DLCO? | 3

Answer 51

Patient quickly inhales a mixture of 0.3% CO and 10% helium Holds their breath for 10 seconds Exhales quickly and measurement obtained

Question 52

Why is CO preferred? (in DLCO) 4

Answer 52

1. not normally present in alveoli/blood 2. transfer is diffusion limited rather than perfusion limited 3. Avidly binds to Hb 4. CO diffusion is less affected by other factors

Question 53

Results of DLCO Low DLCO with obstruction: 2 Low DLCO with restriction: 2 Low DLCO with normal spirometry: 5 High DLCO: 3

Answer 53

1. emphysema 2. In children: cystic fibrosis 1. Pulmonary fibrosis 2. Hypersensitivity pneumonitis 1. Chronic pulmonary emboli 2. Anemia 3. Early interstitial lung disease 4. Increased carboxyhemoglobin level (?) 5. CHF 1. Asthma 2. Left to right intracardiac shunt 3. Polycythemia

Question 54

What test is Used by exercise physiologists, pulmonologists and cardiologists to determine a patient’s functional exercise capacity? What is it based on?

Answer 54

VO2 Testing Based on the Fick equation: VO2 = (SV x HR) x CaO2 – CvO2) VO2 = oxygen uptake

Question 55

The VO2 reflects what? | 3

Answer 55

the maximal ability of a person to take in, transport, and use oxygen—it defines that person’s functional aerobic exercise capacity

Question 56

Clinical Applications for Exercise Testing? | 5

Answer 56

1. Work up for heart transplant 2. Aid in determining the etiology of cardiac vs. pulmonary limitations of exercise 3. Evaluation of a patient who is going to undergo lung resection 4. Evaluation of exercise capacity when indicated for medical reasons in patients in whom the estimates of exercise capacity from exercise test time or work rate is unreliable 5. Objective grading system for patient’s with CHF