Acute respiratory distress syndrome in adults: diagnosis, outcomes, long-term sequelae, and management

Question 1

Characterize ARDS

Answer 1

Acute hypoxaemic respiratory failure with bilateral
infiltrates on chest imaging, which is not fully explained by cardiac failure or fluid overload.

Question 2

What is the Berlin criteria?

Answer 2

The Berlin definition criteria: (1) presence of acute hypoxemic respiratory failure, (2) onset within 7 days of insult, or new (within 7 days) or worsening respiratory symptoms; (3) bilateral opacities on chest x-ray or CT not fully explained by effusions, lobar or lung collapse, or nodules; and (4) cardiac failure not the primary cause of acute respiratory failure.

Question 3

List the predisposing factor of ARDS

Answer 3

• Pneumonia
• Non-pulmonary sepsis
• Gastric aspiration
• Trauma
• Pancreatitis
• Burns
• Inhalation injury
• Drug overdose
• Multiple transfusions
• Shock

Question 4

Classically the histological hallmark of ARDS was described as diffuse alveolar damage. What percentage of patients with ARDS show a diffuse alveolar damage on autopsy?

Answer 4

Less than 50%

Question 5

What is the difference between ARDS and acute hypoxaemic respiratory failure?

Answer 5

The requirement for bilateral
infiltrates on chest imaging (for ARDS).

Question 6

Which criteria of the Berlin definition, might not be needed? and why?

Answer 6

Bilateral infiltrates.
Because outcomes are similar in patients with unilateral or bilateral infiltrates.

Question 7

What tools are used to diagnose ARDS?

Answer 7

• Radiographs
• The Radiographic Assessment of Lung Oedema score.
• The ARDS detection Tool (Artificial intelligence) still in research
• Ultrasound imaging

Question 8

Which tool is under-recognised in clinical settings?

Answer 8

Chest radiographs - suboptimal interobserver reliability.

Question 9

What other diagnostic tool could be used in resource-limited settings?

Answer 9

Oxygen saturation, measured by pulse
oximetry, and fraction of inspired oxygen ratio (SpO2/FiO2 ratio) and lung ultrasound

Question 10

What are the limitations of these tools?

Answer 10

High rate of false positive and pulse oximetry could cause disparities in the
identification of occult hypoxaemia due to skin colour.