Determination of the Optimal Spontaneous Breathing Trial During Weaning of Mechanical Ventilation

Inclusion Criteria: * ICU patient with invasive mechanical ventilation for at least 24 hours * Physician decision to extubate and all criteria for ventilatory weaning must be present * Resolution of disease acute phase for which the patient was intubated * Conscious patient (Richmond Agitation-Sedation Scale (RASS) \> 0), no sedation * Good coughing effort, good swallowing, positive leak test (\> 12% of tidal volume (VT)) * No important secretions * No respiratory acidosis, adequate oxygenation (PaO2 / FiO2 \> 150 mmHg and CPAP ≤ 8) * Adequate pulmonary function (respiratory rate (RR) ≤ 35, negative inspiratory force (NIF) \> 20 cmH2O, RR/VT \< 105) * Stable cardiovascular status (heart rate (HR) \< 140 bpm, systolic blood pressure \> 90 mmHg, no or minimal vasopressors) * If severe brain injury, the VISAGE score must be ≥ 3 (visual pursuit, good swallowing, GCS \> 10) Exclusion Criteria: * Obese patients with BMI ≥ 35 kg/m2 * Contraindication for nasogastric tube or esophageal manometric balloon placement * 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