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

Patient Ventilator Interaction During Non-invasive Ventilation Delivered With Neurally Adjusted Ventilatory Assist (NAVA-NIV) in Infants

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. To test the hypothesis that NAVA could provide better patient-ventilator synchrony during NIV delivered by nasal-facial mask as compared to conventional flow-triggered PSV in infants with Acute Respiratory Failure.

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).

Inclusion Criteria: Infants aging > 1 month and < 2 yrs ARF (PaO2/FiO2 < 300 mmHg) Accessory muscle recruitment Respiratory Rate more than 2 SD related to age Intact neuromuscular pathway to the diaphragm Exclusion Criteria: Hemodynamic instability Facial Surgery Reduction in airway protection Coma Contraindication to insert the nasogastric catheter Heart and lung transplant Increase in PIC Refusal of the parents or legal guardian Enrolment in other research protocols

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