proportion to the measured electrical activity of the diaphragm. This helps to limit the periods of insufficient assist delivery that could induce respiratory muscle fatigue with increased oxygen consumption, and periods of overassistance that can generate intrinsic PEEP with an inadequate increase in intrathoracic pressure [13] . NAVA can also prevent air swallowing and gastric distension by optimization of patient-ventilator synchrony [14] . Third, it is likely that NAVA can help clinician avoiding inappropriate ventilator settings that overload (or underload) respiratory muscles, preventing recovery. Finally, improvements in pulmonary gas exchange, systemic blood flow and oxygen supply to tissues which have been observed when spontaneous breathing has been maintained during mechanical ventilation with clinical improvement in the patient's condition [15] , are assumed to occur in NAVA, when breathing efforts by the patient and the initiated breaths are in synchrony.