Despite spectacular advances since the 90s mechanical ventilation used in intensive care units are amply associated with cardio-respiratory complications: nosocomial pneumonia, lung parenchyma lesions induced by ventilation, hemodynamic instability and ultimately to a significant morbidity and mortality.

NAVA (Neurally Adjusted Assist Ventilation) ventilatory support, provides synchronous support, proportionate to patient's respiratory efforts. More "physiological", this mode would decline its efficacy on patient hemodynamic response. However, to date, no study has focused on hemodynamic impact of NAVA. This is precisely the purpose of NAVADYN11 study, which aims to assess NAVA efficacy on cardiac index in pediatric intensive care unit.

Inclusion criteria:

• Servo-i with NAVA available at patient admission
• Sedation protocol compatible with NAVA functioning
• Parental consent

Non inclusion criteria:

• Digestive pathology incompatible with gastric tube.
• Deep sedation required defined by score ComfortB <11 (cranial traumatism…)
• Brain damage incompatible with spontaneous ventilation
• Duration of intubation too short for investigation

Exclusion criteria:

• Clinical worsening requiring treatment and/or management inconsistent with NAVADYN11 research (CPR, emergency surgery ...). However, the investigator is allowed to reiterate investigation when patient stabilized.