Acute respiratory distress syndrome (ARDS)

Question 1

Describe what acute respiratory distress syndrome (ARDS) is and its cause

Answer 1

• Lung damage and release of inflammatory mediators cause increased capillary permeability and non-cardiogenic pulmonary oedema, often accompanied by multiorgan failure
• It may be caused by direct lung damage or occur secondary to severe systemic illness.

Question 2

List some of the potential causes of ARDS

Answer 2

• Infection: sepsis, pneumonia
• Massive blood transfusion
• Trauma
• Smoke inhalation
• Acute pancreatitis
• Cardio-pulmonary bypass

Question 3

What are the clinical features suggestive of ARDS?

Answer 3

• Tachypnoea
• Tachycardia
• Cyanosis - low O2 sats
• Peripheral vasodilatation
• Bilateral lung crackles

Question 4

What is the diagnostic criteria for ARDS?

Answer 4

The presence of the following 4 criteria:

1. Acute onset (<1 week of a known risk factor)
2. CXR shows - Pulmonary oedema: bilateral infiltrates
3. Pulmonary capillary wedge pressure < 19mmHg or a lack of clinical congestive heart failure
4. Refractory hypoxaemia with PaO2:FiO2 < 200

Question 5

What are the 2 key investigations for the diagnosis of ARDS?

Answer 5

A CXR and ABG’s

Question 6

What is the management of ARDS?

Answer 6

• due to the severity of the condition patients are generally managed in ITU
• oxygenation/ventilation to treat the hypoxaemia
• general organ support e.g. vasopressors as needed
• treatment of the underlying cause e.g. antibiotics for sepsis
• certain strategies such as prone positioning and muscle relaxation have been shown to improve outcome in ARDS