Sonographic Evaluation of Diaphragmatic Function in Critical Care Patients With Use of Non Invasive Ventilation

Usefulness of non invasive ventilation in patients extubated after more than 48 hours of invasive ventilation is still in debate except for specific patients (chronic pulmonary disease and chronic heart failure). Many experimental and clinical studies have shown that diaphragmatic function is depressed by mechanical ventilation in intubated patients. The investigators will test the hypothesis that non invasive ventilation after extubation may improve diaphragmatic function