Respiratory

Acute Respiratory Distress Syndrome (ARDS)

ARDS is acute diffuse inflammatory injury of the alveolar-capillary barrier causing bilateral pulmonary opacities and severe hypoxaemic respiratory failure not fully explained by cardiac failure or fluid overload; treat the trigger while delivering lung-protective critical care and escalating early when oxygenation remains refractory.

Definition

ARDS is acute diffuse inflammatory lung injury with bilateral pulmonary opacities and hypoxaemic respiratory failure that is not fully explained by cardiac failure or fluid overload. Severity is graded by the PaO2/FiO2 ratio under positive end-expiratory pressure, and the syndrome occurs in the context of a recognised direct or indirect insult.

First principles

ARDS is permeability oedema rather than simple hydrostatic oedema

Inflammatory injury to the alveolar epithelium and capillary endothelium makes the barrier leaky, allowing protein-rich fluid into the airspaces. Cardiac failure or fluid overload can coexist, but they must not fully explain the respiratory failure. This is why echocardiographic and clinical assessment of cardiac and volume status matters, and why diuresis alone is not definitive treatment.

You’ve reached the end of the preview

The rest of this extended textbook page is part of full access. Create a free account to read the sample topics in full and try sample questions, then upgrade to unlock every high-yield and extended page, plus the complete question bank.

This page is exam revision material, not medical advice, and must not be used for patient care. Always check drug doses against the BNF and current guidance. Full disclaimer.