As in many pediatric intensive care units, our rate of intubation of children hospitalized for bronchiolitis is tidal volume became much more variable from one cycle to another. Middle panels: One of the most remarkable changes observed with switching to the NAVA mode was the immediate reduction in the mean airway pressure (C) and in the peak airway pressure (D) which decreased from 30 to 10 cm H 2 O. Bottom panels: After starting NAVA, the respiratory rate became very variable over time (E). From a mandatory frequency set at 30 breaths per minute, respiratory rate increased to 40 and 60 breaths per minute. Clinically, the breathing became easier with harmonious chest movements. (F) Edi max that it is the sum of inspiratory Edi and Edi min corresponds to the peak of electrical activity of the diaphragm. In SIMV, this activity is depressed, and in NAVA, the inspiratory Edi (Edi max -Edi min) drives ventilation. Abbreviations: FiO 2 , fraction of inspired oxygen; Edi, electrical activity of the diaphragm; SIMV, synchronized intermittent mandatory ventilation. [5.7] Data in bold are prescribed settings. Other data are measured parameters that depend both on the ventilatory settings and the respiratory status of the child. * Data expressed in parentheses represent measurements that were very variable over time, and hence an estimate of the measured parameter is provided. Abbreviations: SIMV, synchronized intermittent mandatory ventilation; NAVA, neurally adjusted ventilatory assist; PEEP, positive end-expiratory pressure; FiO 2 , fraction of inspired oxygen; Edi, electrical activity of the diaphragm Figure 2 Screenshot with trends over 24 hours (case 1). In the window untitled "Courbes de tendances" (Trend curves), three panels report trends over 24 hours of peak inspiratory pressure (cm H 2 O), respiratory rate (resp/mn), and minute volume (l/min). On the right of these panels, the values of these ventilatory parameters were collected to the vertical bar (at 18:57 while the child was not receiving NAVA). The downward vertical arrow indicates the switch from SIMV to NAVA (at 20:30). Outside the window untitled "Courbes de tendances", on the right of the scrennshot, ventilatory parameters were collected the next day at 10:15 while the child was receiving NAVA. The upper pannel showed a decrease in peak inspiratory pressure after the switch of ventilation. The middle pannel showed the extreme variability of the respiratory ratein NAVA (the white area under the curve corresponds to the mandatory respiratory rate, while the black area corresponds to the spontaneous respiratory rate). The lower pannel showed minute volume that remained unchanged. When comparing values of ventilatory parameters in SIMV (at 18:57) with those in NAVA (next day at 10:15), peak inspiratory pressure decreased from 29 to 6 cm H 2 O, mean airway pressure decreased from 10 to 4 cm H 2 O, spontaneous respiratory rate varied from 0 to 29 breaths/min. Abbreviations: SIMV, synchronized intermittent mandatory ventilation; PEP, positive end-expiratory pressure; P crête, peak inspiratory pressure; P moyen, mean airway pressure; FR spont, spontaneous respiratory rate; F resp, respiratory rate; VM, minute volume; FiO 2 , fraction of inspired oxygen. low (< 20%) [7] . However, the severity of lung disease in some children still necessitates invasive mechanical ventilation. Our unit recruitment is both medical and surgical, and we therefore acquired expertise in NAVA through the weaning of children treated after cardiac surgery. We then expanded the indications of this mode of ventilation in children with severe respiratory disease. The positive results in the present study may be explained by the specific selection of children to whom we applied NAVA. First, there should be no specific contraindication to the placement of a nasogastric tube. Second, there should be no alkalosis or hypocapnia (in such cases there would not be sufficient diaphragmatic electrical activity). During alkalosis, the ventilatory brain centers no longer stimulate the diaphragm, and the respirator works on a backup mode, which is simply conventional ventilation. Finally, the level of sedation should not be too high, so that it does not depress brain centers that control breathing. If the sedation is too high, the Edi signal cannot be collected and the respirator works again in a backup mode. Likewise, neuromuscular connection from the respiratory center to the diaphragm must be intact. For example, NAVA cannot be used in case of post-surgical lesion of the two phrenic nerves [3] or diaphragmatic paralysis secondary to botulism [8] .