Adjusted Ventilatory Assist (NAVA-NIV) in Infants: Short-term Physiological Study

Neurally Adjusted Ventilatory Assist (NAVA) is a new form of partial support wherein the machine applies positive pressure throughout inspiration in proportion to the Electrical Activity of the diaphragm (EAdi), as assessed by trans-esophageal electromyography. Because ventilator functioning and cycling are under control of the patient's respiratory drive and rhythm, NAVA has the potential to enhance patient-ventilator interaction ensuring synchrony and minimizing the risk of over-assistance. A high incidence of asynchrony events has been demonstrated to have a significant clinical impact by favouring weaning failure and longer duration of mechanical ventilation. NAVA has been implemented safely in animals, in healthy volunteers and in critically ill adults and has been shown to improve patient-ventilator synchrony, to limit excessive airway pressure and tidal volume, and to unload the respiratory muscles in tracheally intubated patients. Moreover NAVA was found to be effective in delivering non-invasive ventilation (NIV) even when the interface was excessively leaky (75% leak) with reduced positive end-expiratory pressure. With these conditions, NAVA was able to unload the respiratory muscles and preserve gas exchange, while maintaining synchrony to respiratory demand. To date, no data exist on the use of NAVA in infants during noninvasive ventilation. The aim of this physiological study is to compare patient-ventilator interaction in infants receiving NIV by NAVA and Pressure Support Ventilation (PSV).