Mechanical ventilation in COPD requires a good interaction Patient-Ventilator without asynchronies in order to reduce mortality. Dynamic hyperinflation with PEEPi is responsible for major asynchronies in COPD. It is supposed to be symmetrical between the 2 lungs with the same PEEPi. EIT can measure the distribution of tidal ventilation and interlung lung insufflation delay on the impedance time curve of each lung. Moreover, it is possible in intubated COPD patients to assess one lung PEEPi during low flow insufflation with pressure-EIT monitoring. This study aims to measure interlungs insufflation delay under mechanical ventilation in COPD patients