title: Patient-ventilator interaction during neurally adjusted ventilatory assist in low birth weight infants.
abstract: Neurally adjusted ventilatory assist (NAVA), a mode of mechanical ventilation controlled by diaphragmatic electrical activity (EAdi), may improve patient-ventilator interaction. We examined patient-ventilator interaction by comparing EAdi to ventilator pressure during conventional ventilation (CV) and NAVA delivered invasively and non-invasively. Seven intubated infants [birth weight 936 g (range, 676-1266 g); gestational age 26 wk (range, 25-29)] were studied before and after extubation, initially during CV and then NAVA. NAVA-intubated and NAVA-extubated demonstrated similar delays between onset of EAdi and onset of ventilator pressure of 74 +/- 17 and 72 +/- 23 ms (p = 0.698), respectively. During CV, the mean trigger delays were not different from NAVA, however 13 +/- 8.5% of ventilator breaths were triggered on average 59 +/- 27 ms before onset of EAdi. There was no difference in off-cycling delays between NAVA-intubated and extubated (32 +/- 34 versus 28 +/- 11 ms). CV cycled-off before NAVA (120 +/- 66 ms prior, p < 0.001). During NAVA, EAdi and ventilator pressure were correlated [mean determination coefficient (NAVA-intubated 0.8 +/- 0.06 and NAVA-extubated 0.73 +/- 0.22)]. Pressure delivery during conventional ventilation was not correlated to EAdi. Neural expiratory time was longer (p = 0.044), and respiratory rate was lower (p = 0.004) during NAVA. We conclude that in low birth weight infants, NAVA can improve patient-ventilator interaction, even in the presence of large leaks.
authors.affiliation: Keenan Research Centre, St Michael's Hospital, Toronto, Ontario, Canada. beckj@smh.toronto.on.ca
authors.forename: Jennifer
authors.initials: J
authors.lastname: Beck
authors.forename: Maureen
authors.initials: M
authors.lastname: Reilly
authors.forename: Giacomo
authors.initials: G
authors.lastname: Grasselli
authors.forename: Lucia
authors.initials: L
authors.lastname: Mirabella
authors.forename: Arthur S
authors.initials: AS
authors.lastname: Slutsky
authors.forename: Michael S
authors.initials: MS
authors.lastname: Dunn
authors.forename: Christer
authors.initials: C
authors.lastname: Sinderby
mesh_terms: D003964:Diaphragm / Q000294:innervation / Q000502:physiology; D005865:Gestational Age; D006801:Humans; D007230:Infant, Low Birth Weight; D007231:Infant, Newborn; D007234:Infant, Premature; D007442:Intubation, Intratracheal / Q000379:methods; D047928:Premature Birth; D012121:Respiration, Artificial / Q000379:methods*; D015656:Respiratory Mechanics; D012815:Signal Processing, Computer-Assisted