[16] Acute Respiratory Distress Flashcards
What is acute respiratory distress syndrome (ARDS)?
A non-cardiogenic pulmonary oedema and diffuse lung inflammation syndrome
What can ARDS often complicate?
Critical illness
What is ARDS common in?
Traumatic brain injury
How does ARDS occur?
Increased permeability of pulmonary microvasculature causing leakage of protein rich fluid into the alveoli
What may increased permeability of pulmonary microvasculature be a manifestation of?
More generalised disruption of endothelium
What can ARDS result in?
Hypoxia and multipleorgan failure
How else can ARDS affect the respiratory systems normal function?
Reduced surfactant production
What are the most common risk factors for ARDS?
- Sepsis
- Massive trauma with shock and multiple transfusions
- Pneumonia
- Hypovolaemic shock
- Gastric aspiration
- Head injury
- Raised ICP
What are the three diagnosis criteria for ARDS?
- Acute onset (within 1 week)
- Bilateral CXR opacities
- PaO2/FiO2 (arterial to inspired oxygen) ratio of ≤300 on PEEP or CPAP ≥ 5cm H2O
What may be in the history of a person with ARDS?
- Relevant injury
- Increasing dyspnoea
- Other precipitating event
What are the potential signs of ARDS?
- Cyanosis
- Tachypnoea
- Tachycardia
- Peripheral vasodilation
- Bilateral fine inspiratory crackles
What investigations can be useful in ARDS?
- FBC, U&E’s, LFT, amylase, CRP, clotting, blood cultures, ABG
- CXR
- Those relevant to clinical scenario
What will a CXR show in ARDS?
Bilateral alveolar shadowing with air bronchograms
What are the differentials for ARDS?
- Acute exacerbation of congestive heart failure
- Bilateral pneumonia
- Acute interstitial pneumonia
- Diffuse alveolar haemorrhage
- Hypersensitivty pneumonitis
What should happen to patients with ARDS?
Be admitted to ITU for supportive therapy and treatment of underlying cause
What may be adequate to maintain oxygenation in early ARDS?
CPAP with 40-60% oxygen
What do most patients with ARDS need to maintain oxygenation?
Mechanical ventilation
What are the indications for ventilation in ARDS?
Severe hypoxaemia (PaO2 8.3 kPa) or PaCO2 >6kPa
What other supportive therapies are required in ARDS?
- Circulatory support
- Invasive haemodynamic monitoring with arterial line
- Inotropes
- Blood transfusion
- Nutritional support
- VTE prevention
- Gastric ulcer prevention
What are inotropes used for in ARDS?
Maintaining cardiac output
Give an example of an inotrope used in ARDS?
Dobutamine
What are the potential complications of ARDS?
- Pneumothorax
- Ventilator-associated pneumonia
- Multiple organ failure
- Pulmonary fibrosis