ARDS Morphology

A patient with ARDS can have severely impaired oxygenation for two very different mechanical reasons. In one pattern, much of the lung is collapsed but potentially recruitable. In another, disease is concentrated in dependent regions while the remaining aerated lung is exposed to much of the delivered breath. The CT pattern helps explain why the same airway pressure may improve one lung and overdistend another. That distinction is useful for assessment and for understanding ventilator responses. It is not, however, a licence to prescribe a focal or non-focal ventilator package independently. Current guidelines apply lung-protective ventilation to ARDS generally, and morphology-tailored ventilation remains investigational. The nurse's high-value work is to recognise the pattern, trend oxygenation and respiratory mechanics, watch the haemodynamic response to PEEP, protect the patient during proning, and escalate abrupt changes promptly.