ABSTRACT
Acute respiratory distress syndrome (ARDS) is a severe form of respiratory failure and is often a result of severe physiological insult. ARDS is characterised by non-cardiogenic pulmonary oedema. It leads to diffuse alveolar and interstitial lung oedema, loss of surfactant and alveolar flooding with a proteinaceous exudate containing macrophages and neutrophils. There should be a known precipitant for ARDS, initiating the inflammatory response causing lung injury. This may be a direct pulmonary cause such as pneumonia, contusion, aspiration or smoke inhalation. Extra-pulmonary/systemic causes include sepsis, trauma, massive transfusion and pancreatitis. Patients present with respiratory distress, including tachypnoea and cyanosis, in conjunction with the signs of the precipitating condition. The prone position offers better ventilation/perfusion matching and less lung base compression by the abdomen. Patients may need to be heavily sedated to tolerate relatively un-physiological ventilation strategies of noncompliant lungs, especially in the prone position.
