IMV to Accelerate Recovery of Lung Function in Veno-venous Extracorporeal Membrane Oxygenation; Lung Rest Or Moderate Mechanical Ventilation in ECMO

Near Apnoeic ventilation (with a respiratory rate of 2 breaths per minute, plateau pressure of 30cmH20 and PEEP set according to the mean airway pressure being delivered during mechanical ventilation prior to randomisation) for a 72 hour period following randomisation

"When all patients are eligible for a trial of ECMO weaning, they will have standardised ECMO weaning trials lasting up to 1 hour with 0 sweep gas flow. 1) One-stage weaning- sweep gas flow rate sequentially decreased to zero 2) Two-stage weaning- fraction of oxygen of sweep gas flow decreased to 0.21 sequentially. Then the sweep gas flow rate decreased to 0 sequentially"