PFT

Question 1

What are PFTs used for?

Answer 1

• Measurement of breathing
• Shows abnormalities in lung function (not disease specific)
• Static Lung Volumes - how much air the lungs can hold
• Dynamic Lung Volumes - the flow of air through the airways, how fast that air can be moved

Question 2

Indications for PFTs

Answer 2

• Diagnostic - evaluate signs and symptoms, measure effects on pulmonary function, assess preoperative risk
• Monitoring - assess therapeutic intervention
• Disability - assess impairment/disability from lung disease

Question 3

Limitations for PFTs

Answer 3

• Muscle weakness
• Inadequate effort
• Poor technique
• Position of patient
• Fatigue

Question 4

Contraindications for PFTs

Answer 4

• Pneumothorax
• Haemoptysis
• Aneurysm
• Cerebral instability
• Recent surgery - eyes, chest, abdomen
• Chest infection (clear for two weeks)

Question 5

Factors influencing airway resistance?

Answer 5

• Types of airflow
• Lung volume
• Elastic recoil
• Airway obstructions

Question 6

What is measured in a PFT?

Answer 6

FVC - Forced vital capacity - volume expired FORCEFULLY - should be 80% or higher

FEV1 - Forced expiratory volume in 1 second - the volume of air a subject can exhale in the first second of a maximal breath out - should be 80% or higher

FVC/FEV1 ratio - looks at the amount expelled within the first second compared with the overall volume achieved - should be 70% or higher to be NORMAL

Question 7

What do Restrictive PFTs show?

Answer 7

• Fast rise with a plateau - FEV1 reached quickly
• FVC = >80%
• FEV1 = <80%
• Ratio = normal or increased (<70%)

Question 8

What do Obstructive PFTs show?

Answer 8

• Slow rise, prolonged time to full expiration
• Total volume may be normal
• FEV1 = <80%
• FVC = <80%
• Ratio = >70%