Work of Breathing Assessment During Weaning From Mechanical Ventilation

"1. Preparation:~ 1. Patient baseline characteristics will be collected.~ 2. Connection of the Indirect Calorimeter to the respiratory circuit.~ 3. Nasogastric tube installation: a specific modified Neurally Adjusted Ventilatory Assist (NAVA) catheter equipped with both microelectrodes for Electrical Activity of the diaphragme (EAdi) monitoring and an esophageal balloon (for esophageal pressure (PES) monitoring) will be installed.~2. Simultaneous recordings of: Oxygen Consumption (VO2) and Energy Expenditure (EE); Esophageal Pressure (PES), Airway Pressure (PAW), respiratory volume and flow; EAdi during (i) Conventional mechanical ventilation (ii) Spontaneous Breathing Trial in Continuous Positive Airway Pressure and (iii) Second period of Conventional mechanical ventilation with the same ventilator parameters set in STEP 1.~3. End of the physiological recordings. Collection of Pediatric Intensive Care Unit (PICU) outcome of patients."