Acute Respiratory Distress Syndrome

Question 1

What is acute respiratory distress syndrome

Answer 1

Acute lung damage

Usually secondary to lung injury/systemic illness

Leading to non cardiogenic pulmonary oedema

Question 2

Common causes of ARDS?

Less common causes?

Answer 2

Sepsis
Pneumonia
Aspiration
Pancreatitis
Major trauma

Less common:
Burns
Fat embolism
Drowning
Transfusion related lung injury

Question 2

Pathophysiology of acute respiratory distress syndrome?

Answer 2

Infection/injury -> within 1 week, diffuse alveolar damage, hyaline membrane formation, decreased surfactant production
-> fluid leaks into alveoli from pulmonary capillaries

Question 3

What criteria is used to diagnose ARDS?

Answer 3

Berlin criteria - 1 of the following:
- Acute onset < 1 week

• Chest x-ray shows bilateral opacities
• Decreased ratio of arterial O2 conc (PaO2) to inspired O2 conc (FiO2) of less than or equal to 300

Question 4

Signs and symptoms of acute respiratory distress syndrome?

Answer 4

Acute onset respiratory failure which worsens and has identifiable trigger

Severe dyspnoea
Tachypnoea
Confusion + presyncope (hypoxia)
Multiorgan failure

Signs: diffuse crepitations

Question 5

Investigations for ARDS?

Answer 5

Viral swab - look for infection triggers (flu, COVID)

sputum culture
Blood culture
Urine culture

ABG - determine hypoxaemia

Serum amylase - pancreatitis

Chest x ray

CT chest - show underlying cause, e.g. pneumonia

Question 6

What chest x ray findings would you get in someone with Acute Respiratory Distress Syndrome?

Answer 6

Bilateral alveolar infiltrates without heart failure signs (Kerley B lines, cardiomegaly)

Question 7

Management of Acute respiratory distress syndrome

Answer 7

Manage underlying cause, e.g. antibiotics for sepsis

Usually ICU management with intubation and ventilation

Maintain mean arterial pressure of >60mmHg.

Transfusion if Hb < 70

Repositioning to prevent ulcers.

DVT prophylaxis

PPI cover to prevent gastric ulceration