Acute Respiratory Distress Syndrome

Question 1

What is ARDS?

Answer 1

Adult respiratory distress syndrome (ARDS), also known as acute respiratory distress syndrome, is an acute respiratory failure occurring within 7 days of the onset of a lung injury.

Question 2

What cuases a diffuse bilateral alveolar injury?

Answer 2

ARDS involves a diffuse bilateral alveolar injury, as a result of inflammation mediated by inflammatory mediators

Question 3

What is ARDS not secondary to?

Answer 3

cardiogenic pulmonary oedema,
pleural effusion
atelectasis.

Question 4

Causes

Answer 4

Pneumonia (most common cause)
Sepsis
Aspiration
Pancreatitis
Transfusion reactions
Trauma and fractures
Fat embolism

Question 5

Presentation

Answer 5

ARDS presents with acute onset respiratory failure which fails to improve with supplemental oxygen, the symptoms of which include severe dyspnoea, tachypnoea, confusion, and presyncope.

Physical examination typically reveals fine bibasal crackles

Question 6

What will a CXR show?

Answer 6

Chest x-ray reveals bilateral alveolar infiltrates, without other features of heart failure (such as cardiomegaly and Kerley B lines).

Question 7

Treatment

Answer 7

Patients with ARDS require transfer to intensive care for cardio-respiratory support, where supportive treatment includes:

Ventilatory support - a low tidal volume is associated with better outcomes.

Haemodynamic support to maintain mean arterial pressure >60 mmHg.

DVT prophylaxis.

Nutritional support with enteral/parenteral means if necessary.

Regular repositioning of patient for pressure ulcer prophylaxis.

Note that antibiotics need only be administered if an infectious cause for the ARDS is identified (such as pneumonia or sepsis).