prone positioning
When you lie on your back, gravity pulls the heavier, fluid-laden parts of the lungs downward — and in a diseased lung those dependent regions near the back tend to flood and collapse while still receiving plenty of blood. Prone positioning is the simple but powerful manoeuvre of turning a patient face-down, so that the previously squashed back of the lung opens up and air and blood flow match more evenly across the whole lung.
Lying face-down redistributes the weight of the heart and abdominal organs off the back of the lungs, helps drain secretions, and makes the lung's ventilation more uniform. The net effect in severe ARDS is better oxygenation and, importantly, less ventilator-induced injury because the strain is spread more evenly. Patients are typically proned for long stretches — around sixteen hours at a time — then turned back, repeated over several days while the lungs recover.
Prone positioning is one of the few interventions shown to improve survival in severe ARDS, and it can also help awake patients on high-flow oxygen. An honest caveat: turning a sedated, ventilated patient face-down is a careful team effort, with risks of dislodging tubes and lines, facial pressure sores, and nerve injury if limbs are poorly padded. The benefit is real but it depends on doing the manoeuvre safely and selecting patients who are sick enough to need it.
A ventilated patient with severe ARDS and stubbornly low oxygen is turned prone by a coordinated team; over the next hour his saturation climbs from 86 to 94 percent.
Turning the patient face-down can reopen collapsed lung and improve oxygenation.
Awake proning — asking a non-intubated, breathless patient to lie face-down — was used widely during COVID-19, though it helps less reliably than proning a ventilated patient.