Further studies are clearly needed to better determine the optimal EAdi target.Noninvasive ventilation, sleep and NAVANIV is a specific clinical situation during which the occurrence of leaks may greatly affect patient-ventilator interactions, thereby complicating the determination of optimal ventilator settings. In a study by Vignaux and colleagues, more than 40% of patients experienced various types of asynchrony during conventional NIV and the asynchrony rate correlated with the level of leakage [83]. With NAVA, assistance is delivered based on neural triggering, which is not affected by leakage. NAVA may thus, in theory, diminish asynchrony events, thereby improving the tolerance of NIV. New software for NIV has been developed using NAVA technology. With this specifically designed algorithm, NIV assistance is triggered and cycled-off by the neural diaphragmatic activity, which would be expected to improve patient- ventilator synchrony during NIV. This hypothesis has not yet been fully investigated.A study of NIV-PSV with a helmet interface in healthy volunteers compared asynchrony with a neural trigger and a conventional pneumatic trigger [59]. Increasing PSV levels and respiratory rates applied with neural triggering and cycling-off produced significantly less impairment of synchrony, trigger effort, and breathing comfort, compared with conventional pneumatic triggering and cycling-off .Cammarotta and colleagues recently compared NAVA and NIV-PSV delivered through a helmet interface in postextubation hypoxemic patients [32]. Ten patients underwent three 20-minute trials of helmet NIV in PSV, NAVA, and PSV again. The authors demonstrated that there was less asynchrony during NAVA than during PSV and no difference in gas exchange, although there were more leaks during NAVA. Moreover it is important to underline that the PSV mode chosen was specifically dedicated to NIV, whereas the NAVA mode dedicated to NIV that is now currently available did not exist at the time of this study.Recent data obtained in low-birth-weight infants indicate that NAVA can maintain synchrony – both in terms of timing and proportionality – even after extubation in patients with an excessively leaky interface under NIV (all infants in this study were ventilated using a single nasal prong) [29].Another consideration for NIV that deserves attention in the near future is the impact on swallowing, phonation, and sleep quality, most notably when NIV is used for several days. Improvements in swallowing performance have been reported in neuromuscular patients receiving MV compared with spontaneous breathing [84,85].