7. Spirometry

Question 1

What are pulmonary function tests used for?

Answer 1

Used to diagnose patients with respiratory symptoms
Used to establish severity and progression of lung disease
Used to assess treatment response
Used to monitor patients on meds with lung toxicity

Question 2

What are pulmonary function tests?

Answer 2

Tests that measure lung volumes, rate of airflow, gas exchange

Question 3

What are the instruments/methods used in PFTs?

Answer 3

Peak flow meter
Spirometry
Diffusing capacity for carbon monoxide (DLCO)

Question 4

What is peak expiratory flow?

Answer 4

Maximum airflow rate attained during forces expiration

Using peak flow meter

Question 5

What is normal expiratory flow rate predicted off?

Answer 5

Ethnicity
Height
Gender
Age

Question 6

What is spirometry used for?

Answer 6

Used to measure some lung volumes

Calculates airflow as volumes are measured over time

Question 7

Which lung volumes can spirometry not measure?

Answer 7

Residual volume
Functional residual capacity
Total lung capacity

Question 8

What can be measured in spirometry?

Answer 8

Forced expiratory volume in 1 second (FEV1)
Forced vital capacity (FVC) - occurs over 6 seconds
FEV1/FVC

Question 9

What is forced vital capacity?

Answer 9

Total amount of air exhaled after maximal inspiration during entire FEV test - occurs over 6 seconds

Question 10

What does an FEV1:FVC <70% indicate?

Answer 10

Obstructive airway disease

Question 11

What is the flow volume loop?

Answer 11

Plot of inspiratory and expiratory flow (y-axis) against volume (x-axis) during performance of maximally faced inspiratory and expiratory manoeuvres

Question 12

What is the FEV1 in obstructive lung disease?

Answer 12

Decreased

How much its decreased below normal provides information about disease severity

Question 13

What is the FVC in COPD?

Answer 13

Initially normal, will decrease in severe disease

Question 14

What is FVC in asthma?

Answer 14

Typically decreased - small airways close prematurely

Question 15

Wha happens if there s air trapping because of small airways collapse?

Answer 15

Total lung capacity and functional residual capacity will be increased because of increased residual volume

Question 16

What are some restrictive lung disease?

Answer 16

Interstitial lung disease

Myasthenia gravis

Question 17

What does DLCO do?

Answer 17

Determines how much oxygen travels from alveoli of lungs to bloodstream i.e. diffusion provides information on alveolar-capillary membrane

Question 18

When may decreased DLCO be present?

Answer 18

Emphysema - decreased SA
Alveolar inflammation - increased thickness
Pulmonary fibrosis - increased thickness
Would all have abnormal spirometry or chest x-ray

Question 19

What does an abnormal DLCO with normal chest x-ray and spirometry suggest?

Answer 19

Problem with vascular part of membrane - idiopathic pulmonary arterial hypertension, chronic thrombi-embolism disease of lung
Need other tests to confirm

Question 20

What will parenchymal lung diseases, such as interstitial lung diseases show?

Answer 20

Restrictive pattern and abnormal DLCO

Question 21

What will restrictive lung diseases related to abnormalities in chest wall such as kyphoscoliosis show in DLCO?

Answer 21

Normal DLCO

Question 22

What will restrictive lung diseases related to neuromuscular disease, for example myasthenia gravis show in DLCO?

Answer 22

Normal DLCO