Acute Respiratory Distress Syndrome (ARDS) Flashcards
What is the cause of ARDS?
Increased permeability of alveolar capillaries leading to fluid accumulation in the alveoli i.e. non-cardiogenic pulmonary oedema.
What is the mortality of ARDS?
40%
What are the causes or ARDS?
Infection: Sepsis, pneumonia Massive blood transfusion Trauma/ Direct lung injury Smoke inhalation Acute pancreatitis Cardio-pulmonary bypass Long bone fractures or multiple fractures (fat embolism) Head injury (can cause sympathetic nervous stimulation leading to acute pulmonary hypertension)
What are the clinical features of ARDS.
Acute dyspnoea and hypoxaemia (days/hours after event) Elevated respiratory rate Bilateral lung crackles Multi-organ failure Rising ventilatory pressures
Typically acute onset and severe
What are the investigations of ARDS?
Chest x-ray
ABG
What is the criteria for ARDS?
American-European Consensus Conference
- Acute onset (within 1 week of known risk factor)
- Pulmonary oedema: bilateral infiltrates in chest x-ray
- Non-cardiogenic (pulmonary artery wedge pressure needed if doubt)
- pO2/FiO2 < 40 kPa (200 mmHg)
What is the management of ARDS?
ITU Oxygenation/ventilation for hypoxaemia General organ support i.e. vasopressors Treatment for underlying causes Prone positioning and muscle relaxation Antibiotic if septic Negative fluid balance i.e. diuretics
(low tidal volume ventilation only)
What is ARDS?
Defined as an acute condition characterized by bilateral pulmonary infiltrates and severe hypoxemia (PaO2/FiO2 ratio < 200) in the absence of evidence for cardiogenic pulmonary oedema (clinically or pulmonary capillary wedge pressure of less than 18 mm Hg).
What happens in the early stage of ARDS?
Exudative phase of injury with associated oedema
What happens in the later stage of ARDS?
Repair and fibroproliferaitive changes. Subsequent scarring may result in poor lung function.
