Pulmonary Function Test

Question 1

What are common causes of dyspnea (SoB)?

Answer 1

Deconditioning (obese)
Cardiac causes
Anemia
Pulmonary Causes (Obstructive vs Restrictive)

Question 2

What is determined in PFT?

Answer 2

• Flow and volume to determine cause of dyspnea

- Determines severity of disease (ie. COPD)

Question 3

How is PFT carried?

Answer 3

spirometry (volume of air blown out over time)

Question 4

What is a normal PFT pattern?

Answer 4

blowing out air in the few seconds and then plateauing
FVC = 5 L
FEV1 = 4L
FEV1/FVC = 0.8

Question 5

What is FEV1?

Answer 5

Forced expiratory volume in 1 second

Question 6

What is FVC?

Answer 6

The forced vital capacity, the total amount of air blown out after a maximum inspiration

Question 7

The shape of the spirogram changes for restrictive disease?

Answer 7

F –> restrictive has the same shape but lower FVC
obstructive has also has a lower FVC and change of shape of the curve (bc air goes out slowly)

FEV1 & FVC lowest with obstructive

Question 8

T or F: FEV1/FVC falls in obstructive diseases

Answer 8

T: bc FEV1 falls much lower than the FVC

Question 9

On a spirogram with starting volumes, why does an obstructive disease start with a high volume?

Answer 9

Because obstructive diseases have a hard time getting air out of the lungs (ie. TLC is higher to hyperinflation)

Question 10

Which type of disease has a lower peak expiratory flow (PEF)?

Answer 10

obstructive

Question 11

T or F: the slower one breathes the lower the airway resistance

Answer 11

T (higher RR increases airflow resistance)

Question 12

T or F: alveoli are more deflated with slower RR

Answer 12

T

Question 13

A deflated alveoli has increased what type of resistance?

Answer 13

Elastic resistance

Question 14

What is the pattern of breathing in obstructive disease?

Answer 14

slow RR, and long breaths to prevent flow from becoming turbulent when exhaled

Question 15

How is airway obstruction defined?

Answer 15

Airway obstruction is defined as FEV1/FVC < 88% predicted (FEV1/FVC < 0.75 in young people; < 0.70 in older people)

Question 16

What are some obstructive diseases?

Answer 16

COPD (emphsema, chronic bronchitis)
	Bronchiectasis
	Sarcoidosis
	Long-standing asthma
	Asthma
	Cystic fibrosis

Question 17

What is airway restriction?

Answer 17

Restriction is indicated by a decreased total lung capacity (TLC). TLC is the lung volume when
the lungs are at their maximum volume. A decreased
vital capacity or FVC does not always indicate restriction.

Question 18

What are some causes of restrictive defectcs?

Answer 18

Lungs that are stiff and difficult to inflate
Pulmonary fibrosis
Thickening of the visceral pleura
Pulmonary edema
Large space-occupying lesion in the lungs
Atelectasis

Chest wall disease
	Obesity
	Structural changes
		Kyphoscoliosis
		Paralyzed diaphragm
		Pectus excavatum
	Respiratory muscle weakness

Pleural space disease
Pneumothorax
Pleural effusion

Question 19

FRC is determined by what?

Answer 19

Balance of chest wall recoil and lung elastic recoil

Question 20

What is called the maximum volume of air that can be exhaled after a full inspiration to TLC?

Answer 20

VC

Question 21

What is called the maximum lung volume?

Answer 21

TLC

Question 22

What is called the minimum lung volume?

Answer 22

RV

Question 23

What is FRC?

Answer 23

the volume of the lungs at the start of a normal tidal volume inspiration

Question 24

What usually happens to lungs in obstructive diseases?

Answer 24

• Hyperinflation (high TLC)
• High RV due to the inability to empty the lungs as narrow airways close as they decrease their diameter during exhalation
• -> causes VC to be decreased in severe airway obstruction
• -> FRC [RV +ERV} must be increased to offset the effects of the increased RV.

Question 25

What happens in obese people and their airways?

Answer 25

In obesity the FRC is decreased and this decreases the diameter of the airways. So, obese people are often mistakenly thought to have an airway disease, like asthma.

Question 26

At high lung volumes, the forced expired flow depends on what?

Answer 26

depends on patient effort, lung recoil, and airway resistance

Question 27

Which pressure depends on effort?

Answer 27

pleural pressure (ie. intrathoracic pressure)

Question 28

What is alveolar pressure (Palv)

Answer 28

summation of pleural pressure and lung recoil pressure (Ppl + Pst)

Question 29

How to calculate flow in high lung volume?

Answer 29

Flow = pressure differences (Palv - Patm)/R

R = total airway resistance

Question 30

At low lung volumes, the forced expired flow depends on what?

Answer 30

At low lung volumes, forced expiratory flow depends
on peripheral airway resistance (Rusaw) and lung recoil (Pst).

Effort (Ppl) is no longer important

Question 31

How to calculate flow in low lung volume?

Answer 31

Flow = Pst/R

R = peripheral airway resistance

Question 32

What affects forced inspiration flow?

Answer 32

During forced inspiration, flow depends on total airway resistance, pleural pressure and lung recoil. Effort (Ppl) is important.

Since 90% of Raw is in the upper airways they are important in determining inspired flow

Question 33

Which measures provides info on small airway function?

Answer 33

FEF 75%

Question 34

T or F: FEV1 is effort dependent and affected by resistance in large airways

Answer 34

T