ABSTRACT
New modes of ventilation generally introduce novel approaches to support delivery.1 Non-invasive ventilation (NIV) can be considered a specific technique, in which the tracheal tube is replaced by an external interface, such as a mask, mouthpiece or helmet. Although, in principle, NIV can be applied using the same ventilator equipment as is used for invasive ventilation, several features make NIV a unique technique. As for mechanical ventilation through an endotracheal tube, the primary reasons for applying NIV are improving gas exchange and reducing inspiratory effort. Although intubated patients commonly receive continuous sedative infusion, those undergoing NIV are awake or only mildly sedated, so that patient comfort becomes a key issue for NIV success. In fact, poor tolerance is not infrequently reported as the primary reason for NIV failure.2,3 In contrast to invasive ventilation, NIV is characterized by almost constant air leaks,4which
interfere with support delivery, causing patient-ventilator mismatch, adding to patient discomfort, and, overall, impairing NIV tolerance.2
