Pulmonary function testing

Question 1

what are pulmonary function testings (PFT’s) a measure of

Answer 1

• measure impairment of lung function, not very closely related to symptoms
• helps to differentiate the causes between respiratory and cardiac causes of breathlessness
• they aid screening resp. diseases in high risk populations (smokers)
• aid in determining the severity and progression of lung disease over time

Question 2

what does PFT not measure

Answer 2

activity limitation or participation restriction

Question 3

what affects normal lung values in PFT

Answer 3

• Gender
• Age
• Height
• Weight
• Ethnic group

Question 4

what are the effects of obesity on lung function

Answer 4

• Decreased chest wall compliance-> decreased FRC&ERV (Expiratory reserve volume) ->decreased ventilation = mild hypoxaemia
• Breathlessness
• Major cause of Obstructive Sleep apnoea

Question 5

What does spirometry fine

Answer 5

• FEV1
• FVC and FEV1/FVC
• flow-volume curve

Question 6

What is the effect of airway obstruction on lung volume

Answer 6

• takes longer to get to FVC
• FVC same
• FEV1 lower

Question 7

What is the effect of airway restriction on lung volume

Answer 7

decreased FVC and FEV1

Question 8

what are the ranges to determine severity of COPD

Answer 8

• 60-80 % mild
• 40-59% Moderate
• < 40% severe

Question 9

what are some examples of obstructive lung disease

Answer 9

• asthma
• COPD
• bronchiectasis

Question 10

what are examples of restrictive lung disease

Answer 10

• Interstitial lung disease
• CW abnormalities (Kyphoscoliosis, ankylosing spondylitis).
• Respiratory muscle weakness

Question 11

what is interstitial lung disease

Answer 11

• The disease cause thickening of the alveoli walls, it is a diffuse parenchymal lung disease
• F>M
• Inflammation -> fibrosis
• Dyspnoea
• PFT reduced
• Desaturate easily with exercise

Question 12

what are the changes to RV

Answer 12

-residual volume
- increases with age and is natural
-usually 20-30% of TLC of young adult
increases in COPD–> due to gas trapped in lungs

Question 13

what is TLCO

Answer 13

• carbon monoxide transfer factor

- used to gain the rate of transfer of carbon monoxide CO from inspired air to pulmonary capillary blood

Question 14

what is the importance of TLCO

Answer 14

• Helps to understand the state of the alveolar-capillary membrane or gas exchange surface
• Clinically a person with reduced TLCO will desaturate quickly with exercise.

Question 15

what is the affect of a low TLCO

Answer 15

• decreased surface area or quality of alveolar capillary bed
• increase VQ mismatch
• decreased Hb
• increased COHb