Randomized crossover study of neurally adjusted ventilatory assist in preterm infants.
OBJECTIVE
To determine whether neurally adjusted ventilatory assist (NAVA), a new method of mechanical ventilation that delivers pressure assistance that is proportional to the electrical activity of the diaphragm (EAdi), could lower the inspiratory pressure and respiratory muscle load in preterm infants supported with ventilators.


METHODS
Twenty-six mechanically ventilated preterm infants were randomized to crossover ventilation with NAVA and synchronized intermittent mandatory ventilation (SIMV) with 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 CO(2). 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. Peak inspiratory pressure (PIP), work of breathing, and peak EAdi with NAVA were lower than those in SIMV with PS. Calculated tidal volume to peak EAdi ratio and PIP to peak EAdi ratio were higher with NAVA. There were no significant differences in mean airway pressure, inspiratory oxygen fraction, and blood gas values. The measurements of vital signs did not differ significantly between the 2 modes.


CONCLUSIONS
NAVA lowered PIP and reduced respiratory muscle load in preterm infants at equivalent inspiratory oxygen fraction and partial pressure of CO(2) of capillary blood in comparison with SIMV with PS.
Department of Pediatrics, Seoul National University College of Medicine, Seoul, Korea.
Juyoung
J
Lee
Han-Suk
HS
Kim
Jin A
JA
Sohn
Jin A
JA
Lee
Chang Won
CW
Choi
Ee-Kyung
EK
Kim
Beyong Il
BI
Kim
Jung-Hwan
JH
Choi
D018592:Cross-Over Studies; D003964:Diaphragm / Q000503:physiopathology; D005260:Female; D006801:Humans; D007223:Infant; D007231:Infant, Newborn; D007234:Infant, Premature; D007235:Infant, Premature, Diseases / Q000628:therapy; D059725:Interactive Ventilatory Support; D007385:Intermittent Positive-Pressure Ventilation / Q000379:methods; D008297:Male; D010100:Oxygen / Q000737:chemistry; D010865:Pilot Projects; D011312:Pressure; D011446:Prospective Studies; D012119:Respiration; D012120:Respiration Disorders / Q000628:therapy; D012121:Respiration, Artificial / Q000379:methods*; D013990:Tidal Volume; D012122:Ventilators, Mechanical
D010100:Oxygen