Why weaning matters
Time on a ventilator is not free. Every day intubated carries a risk of ventilator-associated pneumonia, the breathing muscles waste from disuse, sedation builds up, and the airway itself can be injured. So the moment the underlying problem starts to mend, the team begins thinking about weaning — gradually handing the work of breathing back to the patient. The art is to do it neither too early (and have to re-intubate) nor too late (and accrue harm).
Testing readiness: the breathing trial
- Check the basics are mending: oxygen needs are modest (low FiO2 and PEEP), the original cause is controlled, the patient is awake enough, and they are off (or nearly off) drugs that support the blood pressure.
- Run a spontaneous breathing trial: dial the support down to minimal and let the patient do the work of breathing for 30 minutes to 2 hours while you watch.
- Watch for failure: rising rate, falling oxygen, sweating, agitation, a fast heart, or paradoxical belly movement all say “not yet.”
- If the trial is passed comfortably and the patient can protect their airway and cough, remove the tube (extubate).
When someone needs the tube for many weeks — a slow wean, a brain injury, prolonged weakness — a tracheostomy (a tube placed through a small opening in the neck) is often kinder: it is more comfortable, needs less sedation, makes mouth care and speaking-valve use possible, and protects the vocal cords from a tube rubbing against them for too long.
ECMO: borrowing a lung from outside the body
Sometimes the lung is so badly injured — the worst ARDS, say — that even perfect, gentle mechanical ventilation cannot keep the blood oxygenated or clear the CO2. ECMO (extracorporeal membrane oxygenation) is the last resort: blood is drained from a large vein, pumped through an artificial membrane lung that adds oxygen and removes carbon dioxide, then returned to the body. The machine takes over gas exchange so the real lungs can be ventilated ultra-gently and given time to heal.
For pure lung failure the usual form is veno-venous ECMO (vein to vein), which supports the lungs but not the heart; when the heart is also failing, veno-arterial ECMO supports both. It is extraordinarily resource-intensive, needs blood-thinning that brings real bleeding risk, and is offered in specialist centres to carefully chosen patients. It is crucial to be honest about this: ECMO does not cure the lung — it buys time for the lung to recover or for another treatment to work. If there is no recoverable lung and no path forward, it cannot create one.