Assessment of Human Diaphragm Strength by Magnetic and Electric Stimulation After Ultrasonography Phrenic Nerve Tracking

Inclusion Criteria: * ICU patient with invasive mechanical ventilation * Sedated patient with a Richmond Agitation-Sedation Scale of -4 or -5 Exclusion Criteria: * Contraindication for magnetic stimulation (Pacemaker) * Hemodynamic or respiratory instability : PaO2/FiO2 \< 200 mmHg, noradrenaline \> 0,3 µg/kg/min, dobutamine \> 10 µg/kg/min * Neuromuscular disease or recent use of neuromuscular blocking agents (2h30) with a TOF ratio below 4/4 95%. * Refusal of study participation or to pursue the study by the patient, no consent * Pregnancy or breastfeeding * Absence of coverage by the French statutory healthcare insurance system