3 - Lung function Tests

Question 1

What are the four primary clinical indications for performing respiratory function tests?

Answer 1

Diagnostic, prognostic, screening, and pre-operative.

Question 2

Why can forced expiratory manoeuvres be dangerous for patients with recent eye surgery?

Answer 2

They significantly increase intra-cranial pressure.

Question 3

List three cardiovascular conditions that serve as potential contra-indications for PFTs.

Answer 3

Unstable cardiovascular status, recent myocardial infarction, or pulmonary embolus.

Question 4

Which specific respiratory condition is the primary indication for using Peak Expiratory Flow Rate (PEFR)?

Answer 4

Asthma.

Question 5

How many readings are required for a PEFR test, and which one is recorded?

Answer 5

Three readings are taken, and the best of the three is recorded.

Question 6

An increased likelihood of asthma is indicated by a PEFR diurnal variability of ≥ 20%.

Answer 6

True.

Question 7

What specific airway size does PEFR primarily reflect?

Answer 7

Large airway flow.

Question 8

What are the three basic related measurements obtained during spirometry?

Answer 8

Volume, time, and flow.

Question 9

In spirometry, what is the required minimum duration for the forced exhalation phase?

Answer 9

6 seconds.

Question 10

What is the maximum number of attempts a patient should be given to perform spirometry in one session?

Answer 10

8 tries.

Question 11

According to spirometry quality standards, the best two readings should be within 100 ml or 5% of each other.

Answer 11

True.

Question 12

Term: FEV1

Answer 12

Definition: The volume of gas expired in the first second of forced expiration.

Question 13

Term: FVC

Answer 13

Definition: The total volume of gas expired during a forced expiration manoeuvre.

Question 14

How does an obstructive lung defect typically affect the FEV1/FVC ratio?

Answer 14

The ratio is reduced.

Question 15

What is the hallmark measurement used to define a restrictive lung defect?

Answer 15

Reduced Total Lung Capacity (TLC).

Question 16

How does the FEV1/FVC ratio typically appear in a patient with restrictive lung disease?

Answer 16

It is normal or high.

Question 17

Identify three examples of obstructive lung diseases.

Answer 17

COPD, Asthma, and Bronchiectasis.

Question 18

Identify three examples of restrictive lung diseases.

Answer 18

Pulmonary fibrosis, pleural disease, and chest wall disease.

Question 19

Respiratory muscle weakness typically causes a(n) _____ pattern on lung function tests.

Answer 19

Restrictive

Question 20

Which four demographic factors are required to generate computer-predicted normal spirometry values?

Answer 20

Biological sex, age, height, and ethnicity.

Question 21

The 2022 ATS/ERS guidelines emphasise using _____ sex rather than gender for reference equations.

Answer 21

biological

Question 22

Which reference equations are recommended by the 2022 guidelines for spirometry, lung volumes, and DLCO?

Answer 22

GLI (Global Lung Function Initiative) reference equations.

Question 23

Why is the use of a fixed 0.70 cut-off for the FEV1/FVC ratio discouraged in the 2022 guidelines?

Answer 23

It leads to misinterpretation, particularly in women, children, and older adults.

Question 24

The Lower Limit of Normal (LLN) for FEV1 is age-specific, varying from 81% predicted at age 10 to _____ at age 85.

Answer 24

68% predicted

Question 25

According to the Fletcher-Peto curve, what is the average annual decline of FEV1 in a healthy, non-smoking adult?

Answer 25

20-30 ml per year.

Question 26

What is the typical annual rate of FEV1 decline in smokers susceptible to its effects?

Answer 26

> 60 ml per year.

Question 27

What is the standard adult dose of Salbutamol used via a spacer to test for asthma reversibility?

Answer 27

400 mcg.

Question 28

How long should a clinician wait after administering a bronchodilator before performing post-test spirometry?

Answer 28

At least 15 minutes.

Question 29

What is the 2022 recommended method for reporting bronchodilator reversibility in FEV1 or FVC?

Answer 29

As a 10% increase relative to the predicted value.

Question 30

Under the 2022 guidelines, what z-score range indicates a 'Mild' lung function impairment?

Answer 30

−1.65 to −2.5.

Question 31

Under the 2022 guidelines, what z-score range indicates a 'Moderate' lung function impairment?

Answer 31

−2.51 to −4.0.

Question 32

Under the 2022 guidelines, what z-score indicates a 'Severe' lung function impairment?

Answer 32

< −4.1.

Question 33

What is the clinical definition of a z-score in the context of pulmonary function tests?

Answer 33

How far an observed value is from the predicted value, expressed in standard deviations.

Question 34

What does DLCO (or TLCO) measure regarding lung physiology?

Answer 34

The efficiency of the lungs at transferring gas from inhaled air to red blood cells.

Question 35

Carbon monoxide (CO) binds to haemoglobin with an affinity _____ times greater than oxygen.

Answer 35

200-250

Question 36

Which three physical factors primarily determine DLCO?

Answer 36

Gas pressure difference, membrane thickness, and gas solubility.

Question 37

How much more soluble is CO2 in the alveolo-capillary membrane compared to O2?

Answer 37

20 times.

Question 38

Describe the exhalation step required immediately before the rapid inhalation in the single breath-hold DLCO technique.

Answer 38

Unforced exhalation to Residual Volume (RV).

Question 39

During a DLCO test, how long must the patient hold their breath at Total Lung Capacity (TLC)?

Answer 39

10 seconds.

Question 40

Formula: DLCO

Answer 40

LCO=Va(lungsurfacearea)×Kco (rateofcapillarybloodCOuptake)

Question 41

Name three pulmonary disorders that typically decrease DLCO by affecting the lung parenchyma.

Answer 41

Interstitial Lung Disease (ILD), Emphysema, and Pulmonary Oedema.

Question 42

Which specific condition is a notable exception that causes an increase in DLCO?

Answer 42

Pulmonary haemorrhage.

Question 43

DLCO is particularly useful for detecting _____ stage Interstitial Lung Disease (ILD) before lung volumes significantly reduce.

Answer 43

early

Question 44

Which lung volume remains in the lungs even after a maximal exhalation and cannot be measured by simple spirometry?

Answer 44

Residual Volume (RV).

Question 45

Term: Functional Residual Capacity (FRC)

Answer 45

Definition: The volume of air remaining in the lungs after a normal, passive exhalation.

Question 46

What is the primary purpose of the 6-Minute Walk Test (6MWT)?

Answer 46

To assess endurance and functional limitation in patients with severe respiratory disease.

Question 47

Which clinical parameters are recorded during a 6MWT besides distance covered?

Answer 47

Pre- and post-test breathlessness and blood oxygen saturation levels.

Question 48

What does CPET stand for in the context of respiratory medicine?

Answer 48

Cardio-pulmonary Exercise Testing.

Question 49

Identify two common indications for performing a CPET.

Answer 49

Assessment of pre-operative fitness and evaluation of unexplained shortness of breath.

Question 50

Which test measures the maximum workload capacity of a patient using an incremental increase in resistance?

Answer 50

CPET (Cardio-pulmonary Exercise Testing).