Bedside tests in chest medicine

Question 1

Name 5 bedside tests.

Answer 1

• Sputum examination
• Peak expiratory flow (PEF)
• Pulse oximetry
• Arterial blood gas (ABG) analysis
• Spirometry

Question 2

What can the appearance of a sputum sample tell us? (5)

Answer 2

• clear and colourless – chronic bronchitis
• yellow-green – pulmonary infection
• red – haemoptysis
• black – smoke / coal dust
• frothy white-pink – pulmonary oedema

Question 3

What should be carried out when sending a sputum sample for microscopy? (2)

Answer 3

• Gram stain

* auramine / ZN stain

Question 4

What other tests can be done on sputum sample? (2)

Answer 4

• Culture

* Cytology

Question 5

What is peak expiratory flow (PEF)?

Answer 5

• Is measure by a maximal forced expiration through a peak flow metre.
• Correlates well with FEV1
• Used as an estimate of airway calibre, but is more effort dependent

Question 6

What is pulse oximetry and what is it useful for?

Answer 6

• Non-invasive assessment of peripheral O2 saturation.

* Useful tool for monitoring patients that are acutely ill or at risk of deterioration.

Question 7

What is arterial blood gas (ABG) analysis?

Answer 7

• Heparinised blood is usually taken from the radial or femoral artery , and pH, PaO2 and PaCO2 are measured.

Question 8

What are the normal ranges for: pH, PaO2 and PaCO2?

Answer 8

• pH – 7.35-7.45 – below and above this range indicates acidosis and alkalosis respectively.
• PaO2 – 10.5-13.5kPa
• PaCO2 – 4.5-6.0kPa

Question 9

What causes hypoxia? (4) Which is the most common cause?

Answer 9

• ventilation/perfusion (VQ) mismatch - MOST COMMON
• hypoventilation
• abnormal diffusion
• right to left cardiac shunts

Question 10

What does PaCO2 directly relate to? What is indicated if the value is below or above the normal range?

Answer 10

• alveolar ventilation

* PaCO2 6 = hypoventilation

Question 11

How is type I respiratory value defined?

Answer 11

• PaO2

Question 12

How is type II respiratory failure defined?

Answer 12

• PaO2 6.0kPa

Question 13

What is spirometry?

Answer 13

• measures functional lung volumes.

Question 14

What does the FEV1/FVC ratio provide a good estimate of? What is the normal ratio?

Answer 14

• the severity of airflow obstruction

* 75-80%

Question 15

A FEV1/FVC ratio of

Answer 15

• Obstructive defect – asthma / COPD

* FEV1 is reduced more than the FVC

Question 16

If the FVC is reduced and the FEV1/FVC ratio is equal or increased what does this indicate? Give examples of disease where this occurs. (8)

Answer 16

• restrictive defect
• Lung fibrosis (MOST COMMON) / sarcoidosis / pneumoconiosis / interstitial pneumonias / connective tissue diseases / pleural effusion / kyphoscoliosis / neuromuscular problems