Spirometry and shit

Question 1

How spirometry is performed

Answer 1

• Take a deep breath in
• Exhale as hard as posisble onto the sensor
• Rapidly inhale

This creates a flow-volume loop

Question 2

Forced Expiratory Volume in 1 second (FEV1)

Answer 2

Volume of air that can be forcibly be blown out in one second after full inspiration measured in litres

Question 3

Forced Vital Capacity

Answer 3

Volume of air that can forcibly be blown out after full inspiration (litres)

Question 4

Obstructive lung disease

Answer 4

• Airway obstruction, typically narrowing- makes breathing out air difficult
• e.g Asthma, Copd, oesophageal cancer

Ratio less than 0.7

Question 5

Restrictive lung disease

Answer 5

• Lung capacity restricted- lungs unable to fill up fully
• e.g neuromuscular disorders, obesity, pregnancy etc.

Ratio greater than 0.8

Question 6

Diffusion Capacity

Answer 6

Measure of how well O2 can diffuse from alveoli to capillaries

• Affected by SA, Hb levels and blood supply

Question 7

Measuring Diffusion Capacity

Answer 7

• Patient fully exhales then fully inhales a mixture of 0.3% CO and 10% Helium
• After inhalation, hold breath for 10 seconds
• Patient exhales and mesure levels of CO and He