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.