Noninvasive NAVA Versus NIPPV in Low Birthweight Premature Infants

Very low birthweight (VLBW) premature infants in the NICU (Neonatal Intensive Care Unit)
frequently require respiratory support for prolonged periods of time. Invasive mechanical
ventilation (which requires intubating the baby with a tube to provide breaths) can lead to
ventilator induced lung injury. Because of this, noninvasive respiratory support has become
increasingly popular, as this form of ventilation has been shown to reduce the incidence of
permanent lung injury.

There are several methods to provide non-invasive support. The gentlest is continual flow of
air and oxygen via nasal cannula. However, premature infants often develop apnea, either
because the signals from their immature brain are not yet sufficient or because the muscles
in the back of their throat do not get enough nerve signals to maintain sufficient opening.
As a result, babies on nasal cannula often develop clinical apnea/bradycardia/desaturations.
Before putting these babies back on invasive ventilation, clinicians often try to provide the
baby with machine breaths while still on non-invasive ventilation.

This method is called nasal intermittent positive pressure ventilation and studies have
demonstrated that this method reduces the need for re-intubation in VLBW infants (1) and
reduces the rate of apneic events.

A newer method of non-invasive breathing support that has been FDA approved and used in VLBW
infants, synchronizes the machine generated breath with the patient's own breath. Neurally
adjusted ventilatory assist (NAVA) does this by replacing the standard nasogastric tube with
a nasogastric tube that has sensors which detect the baby's natural diaphragm activity, which
signal the ventilator to breath in synchronization with the baby. Studies have shown that the
efficacy of nasal ventilation is significantly enhanced when the machine breath is
synchronized with the patient breath (2). Synchronization also reduces diaphragmatic
dysfunction (3). It can improve gas delivery, reduce work of breathing, and make patients
demonstrably more comfortable (4).

Neurally Adjusted Ventilatory Assist (NAVA) is a mode of partial support. NAVA can be used
both in intubated patients (invasive NAVA) as well as in extubated patients who require
noninvasive positive pressure ventilation (noninvasive NAVA) (5). Invasive NAVA has been
shown to deliver equivalent ventilation while requiring lower peak inspiratory pressure, as
well as reduced respiratory muscle load, compared to conventional pressure support
ventilation.

Currently, the choice of using NIPPV or NAVA is at the clinician's discretion. Both are
regularly and frequently used in the VCU (Virginia Commonwealth University) Health System's
NICU. There are no studies that have examined whether NAVA triggered synchronized ventilation
is more effective than nonsynchronized NIPPV. In addition, there is limited data on the
synchronicity and mechanics of non-invasive NAVA in VLBW infants. Information comparing
clinical and lung mechanical outcomes between NIPPV and NIV (Nasal noninvasive ventilation)
NAVA would significantly benefit VLBW care providers and, consequently, their patients in
getting the best evidenced based therapy.

Inclusion Criteria:

- < 1501 grams (VLBW (very low birth weight) infant)

- Patient must be receiving daily caffeine therapy for apnea

- On non-invasive ventilation, either NIPPV or non-invasive NAVA

Exclusion Criteria:

- No concerns for acute sepsis (i.e., blood cultures, if drawn, have been negative for
48 hours, and no active signs/symptoms of sepsis).

- No history of meningitis or seizures

- No signs of increased intracranial pressure, including bulging fontaneIle, presence of
ventricular shunt device, or ventriculomegaly by most recent ultrasound.

- Presence of Grade III or IV intraventricular hemorrhage

- No cyanotic heart defects or clinically significant congenital heart disease. Will
allow PDA (patent ductus arteriosus), PFO (patent foramen ovale), and mild to moderate
ASD (atrial septal defect)/VSD (ventricular septal defect) as determined by pediatric
cardiology.

- Non -English speaking legal representatives (parents)