Introduction
Neurally adjusted ventilatory assist (NAVA) has been developed and evaluated in many studies, including studies of preterm infants, over the last decade. This technique uses the electrical activity of the diaphragm (Edi) to control respiratory support and the NAVA level as an amplification factor that converts the Edi signal into a proportional pressure.1 NAVA synchronizes mechanical breaths with the patient’s neural respiratory drive and supports this drive proportionally to its effort.1–3 Several studies have demonstrated that the patient-ventilator interaction is improved and that delivered pressure is decreased with NAVA compared with other conventional modes in preterm infants.4–9
NAVA uses the patient’s own respiratory effort as both a trigger and an assist control during respiratory support.1,10 Because of these characteristics, many clinicians are concerned if the weak respiratory effort of preterm infants would hinder NAVA working efficiently for them.11–14 This is one of the important obstacles causing hesitation regarding the use of NAVA in preterm infants. Additionally, there is a paucity of research on the use of NAVA in the most immature preterm infants.
We aimed to investigate the success of NAVA ventilation at different gestational ages in preterm infants by analyzing the proportion of backup ventilation during NAVA. In addition, the trends in backup ventilation were analyzed in relation to clinical deteriorations.