Comparison of Work of Breathing Between Noninvasive Ventilation and Neurally Adjusted Ventilatory Assist in a Healthy and a Lung-Injured Piglet Model

BACKGROUND: Noninvasive ventilation (NIV) is commonly used in neonates. A mode of NIV called neurally adjusted ventilatory assist (NAVA) offers patient-ventilator interactions by using electrical activity of the diaphragm to control mechanical breaths. We hypothesized that the work of breathing (WOB) would decrease with NIV-NAVA. Secondary objectives evaluated the impact of NIV-NAVA on arterial blood gases and respiratory parameters. METHODS: We compared WOB between synchronized breaths in NIV-NAVA and NIV in piglets with healthy lungs and then with surfactant-depleted lungs. Neonatal pigs (median, 2.0 [range, 1.8-2.4] kg) with healthy and then surfactant depleted lungs were sedated and ventilated with NIV-NAVA and NIV in random order. Airway flow and pressure waveforms were acquired. Waveforms were analyzed for the pressure-time product that reflected WOB. The primary outcome between modes was assessed with repeated measurement analysis of variance. RESULTS: The pressure-time product was significantly decreased for NIV-NAVA in both healthy and injured lungs (P <.001). P-aO2, P-aCO2, inspiratory tidal volume, and peak inspiratory flow were not different in either model. CONCLUSIONS: Synchronized breaths during NIV-NAVA resulted in decreased WOB compared with synchronized breaths during NIV.