Randomized Crossover Study of Neurally Adjusted Ventilatory Assist (NAVA) in Preterm Infants

Abstract

Introduction: Neurally adjusted ventilator assist (NAVA) is a new method of mechanical ventilation, which delivers pressure assistance that is proportional to the electrical activity of the diaphragm. Methods: To find out whether NAVA can be used to improve the lung-protective ventilator care of preterm infants, a prospective, randomized controlled, crossover clinical trial was performed. Twenty-six mechanically ventilated preterm infants were assigned to crossover ventilation with NAVA and synchronized intermittent mandatory ventilation (SIMV) + pressure support (PS) for 4 hours each in a randomized order. A 1-hour interval for washout was provided between the 2 modes of ventilation. The ventilator settings were adjusted to maintain similar levels of end-tidal partial pressure of CO2 (EtCO2). The ventilator parameters, vital signs, and gas exchange effects under the 2 ventilatory modes were compared. Results: Nineteen infants completed the 9-hour crossover comparison protocol. The peak inspiratory pressure (PIP), work of breathing (WOB) and peak electrical activity of the diaphragm (EAdi) with NAVA were significantly lower than those in SIMV + PS (P = 0.043, 0.002 and 0.004, respectively). Calculated tidal volume to peak EAdi ratio and PIP to peak EAdi ratio were higher with NAVA (P = 0.003 and 0.017, respectively). There were no significant differences in the mean airway pressure, inspiratory oxygen fraction (FiO2) and blood gas values. None of the measurements of vital signs differed significantly between the two modes. Conclusions: NAVA lowered PIP and reduced WOB in preterm infants at equivalent FiO2 and partial pressure of CO2 of capillary blood in comparison to SIMV + PS.