Pulmonary Function Tests

Question 1

What are some of the indications for doing pulmonary function testing?

Answer 1

Patient presents with possible pulmonary disease

Monitor patients with known pulmonary disease

Investigation in diseased patients with possible respiratory complications

Pre-op evaluation

Evaluation of patients at risk of lung disease

Surveillance following lung transplant

Question 2

One of the indications for performing PFTs is investigation of patients with presentation suggesting pulmonary disease. What symptoms might these patients present with, prompting you to perform pulmonary function testing?

Answer 2

Cough
Wheezing
Breathlessness
Crackles
Abnormal chest X ray

Question 3

One of the indications for performing PFTs is to monitor patients with known pulmonary disease to track progression or response to treatment. What are some conditions that require monitoring with PFTs?

Answer 3

Interstitial fibrosis
COPD
Asthma
Pulmonary vascular disease

Question 4

One of the indications for performing PFTs is investigation of patients with disease that may have respiratory complications. What are a couple examples of disease that may have respiratory complications?

Answer 4

Connective tissue disorders

Neuromuscular disorders

Question 5

One of the indications for performing PFTs is for pre-op evaluation. What are some types of operations require PFTs in pre-op?

Answer 5

Lung resection
Abdominal surgery
Cardiothoracic surgery

Question 6

One of the indications for performing PFTs is to evaluate patients at risk of lung disease. This may be done if a patient is exposed to what types of things?

Answer 6

Pulmonary toxins like radiation, medication, or environmental or occupational exposure

Question 7

One of the indications for performing PFTs is surveillance following lung transplant. What are these PFTs assessing for?

Answer 7

Acute rejection
Infection
Obliterative bronchiolitis

Question 8

What are some contraindications for performing PFTs?

Answer 8

Myocardial infarction within the last month
Unstable angina
Recent thoracoabdominal surgery
Recent ophthalmic surgery
Thoracic or abdominal aneurysm
Current pneumothorax

Question 9

T/F: active respiratory infections like tuberculosis are absolute contraindications to performing pulmonary function testing

Answer 9

False: patients with active infections such as Tb are not precluded from having PFTs, but they should be deferred until risk of cross contamination is negligable

Question 10

What position is the patient recommended to be in for PFTs?

Answer 10

Seated; if standing there is risk of syncope

[however they can be performed standing]

Question 11

What are the recommendations in terms of smoking, eating, and clothing prior to pulmonary function testing?

Answer 11

Patient advised not to smoke for 1 hour prior

No large meals 2 hours prior

No restrictive clothing

Question 12

How many times should PFTs be performed in order to ensure reproducibility?

Answer 12

3x with less than 200 mL variation

Question 13

What are the 3 primary pulmonary function tests?

Answer 13

Spirometry
Flow volume curves
Peak expiratory flow rate

Question 14

How does spirometry work?

Answer 14

Patient takes maximal inspiration and forcefull expels as long a they can, as quickly as they can

[called the forced vital capacity maneuver]

Question 15

What measurements are obtained with spirometry?

Answer 15

FEV1
FVC
FEV1:FVC ratio

[spirometry measures volume against time]

Question 16

What does the patient do to obtain a reading for flow volume curve PFT?

Answer 16

Patient performs maximal inspiratory maneuver followed by max expiratory effort

Question 17

Flow volume curves show a positive ________ limb, and a negative _________ limb.

A. Inspiratory; expiratory
B. Inspiratory; inspiratory
C. Expiratory; inspiratory
D. Expiratory; expiratory

Answer 17

C. Expiratory; inspiratory

Question 18

The max flow rate during expiration during the flow volume curve PFT can be measured as the _____ ______ _____ rate

Answer 18

Peak expiratory flow

Question 19

What are some other PFTs that are less common than the spirometry, flow volume curve, and peak expiratory flow rate?

Answer 19

Static lung volume
Bronchodilator testing
Diffusion capacity

Question 20

Static lung volumes cannot be measured via spirometry. What are some methods for measuring static lung volumes?

Answer 20

Whole body plethysmography in airtight body box

Nitrogen washout

Helium dilution

Question 21

What is the purpose of diffusion capacity PFT?

Answer 21

Gives information about the integrity and size of alveolar blood membranes

It measures the diffusion of gas across the alveolar membrane which is determined by the surface area and integrity of alveolar membrane and pulmonary vascular bed

Question 22

What type of lung disease causes a limitation in flow rate and is the more common type?

Answer 22

Obstructive

Question 23

Describe intrathoracic airway obstruction

Answer 23

Upper part of lumen has greater pressure than intrathoracic pressure

Almost always due to tumor in major airway, often caused by smoking

Question 24

Describe variable extrathoracic obstruction

Answer 24

Occurs outside pleural reflection; creates positive intrathoracic pressure. Pressure is also positive in lumen of airway.

Often due to vocal cord tumors or vocal cord spasm/muscle dysfunction

Question 25

What are some examples of obstructive lung diseases?

Answer 25

COPD
Chronic bronchitis
Emphysema
Asthma
Bronchiectasis

Question 26

A patient presents to your clinic with shortness of breath. You perform pulmonary function testing and the only abnormal finding is a reduction in expiratory reserve volume. What is your likely diagnosis?

Answer 26

Obesity

Question 27

A patient presents to your clinic with shortness of breath. You perform pulmonary function testing and the only abnormal finding is a reduction in diffusion capacity. You run some further tests but cannot determine any other obvious respiratory cause. What is your likely diagnosis?

Answer 27

Pulmonary embolism

Question 28

What effect does obstructive lung disease have on the FEV1:VC ratio determined by spirometry?

Answer 28

Decreased

Question 29

Obstructive lung disease causes a loss of elastic recoil and radial support. What changes might you see on the flow volume loop in a patient with COPD?

Answer 29

Concave appearance to desscending portion of expiratory limb (rather than straight line)

Question 30

The flow volume loop may appear normal in a patient with asthma, except for which value?

Answer 30

Peak expiratory flow rate will be reduced

Question 31

A patient presents to your clinic with shortness of breath. You run some basic PFTs and find some flattening of the expiratory limb while the inspiratory limb appears normal. What is your likely diagnosis?

A. Obesity
B. Intrathoracic obstruction
C. Fixed extrathoracic obstruction
D. Restrictive pulmonary disease

Answer 31

B. Intrathoracic obstruction

Question 32

A patient presents to your clinic with shortness of breath. You run some basic PFTs and find that the expiratory limb has a convex appearance on their flow volume loop. In addition, they have a low vital capacity but a normal FEV1:VC ratio. What is your likely diagnosis?

A. Obesity
B. Intrathoracic obstruction
C. Fixed extrathoracic obstruction
D. Restrictive pulmonary disease

Answer 32

D. Restrictive pulmonary disease

Question 33

What change occurs in the total lung capacity with restrictive pulmonary disease?

Answer 33

Decrease

Question 34

What changes occur in the total lung capacity and diffusion capacity in a patient with obstructive pulmonary disease?

Answer 34

TLC increase

Diminished diffusion capacity

Question 35

A patient presents to your clinic with shortness of breath. You run some basic PFTs and find symmetric flattening of both the inspiratory and expiratory limbs on their flow volume loop. What is your likely diagnosis?

A. Obesity
B. Intrathoracic obstruction
C. Fixed extrathoracic obstruction
D. Restrictive pulmonary disease

Answer 35

C. Fixed extrathoracic obstruction