OBJECTIVENeurally adjusted ventilatory assist (NAVA) is a new mode of mechanical ventilation that delivers ventilatory assist in proportion to neural effort. This study aimed to compare the hemodynamic safety, oxygenation and gas exchange effects ventilated with NAVA and with pressure support ventilation (PSV) in infants who underwent open-heart surgery.

METHODSTwenty-one infants who underwent open-heart surgery for congenital heart disease (mean age 2.9+/- 2.1 months and mean weight 4.2+/- 1.4 kg) were enrolled. They were ventilated with PSV and NAVA for 60 minutes respectively in a randomized order. The hemodynamic, oxygenation and gas exchange effects produced by the two ventilation modes were compared.

RESULTSThree cases failed to shift to NAVA because of the bilateral diaphragmatic paralysis after operation. In the other 18 cases, there were no significant differences in the heart rate (HR), systolic blood pressure (BPs) and central venous pressure (CVP) in the two ventilation modes. The PaO2/FiO2 (P/F) ratio in NAVA was slightly higher than in PSV, but there was no statistical difference. PaCO2 did not show significant differences in the two modes. The peak inspiratory pressure (PIP) and electrical activity of the diaphragm (EAdi) in NAVA were significantly lower than in PSV. The EAdi signal after extubation was higher in infants who needed reintubation or intervention of noninvasive mechanical ventilation than in those who were extubated successfully (30.0+/- 8.4 microV vs 11.1+/- 3.6 microV; P<0.01).

CONCLUSIONSAs the first study of application of NAVA in infants in China, this study shows that NAVA has the same homodynamic effects as PSV. However the PIP for maintaining the same level of PaCO2 in NAVA is significantly lower than that in the traditional PSV. Monitoring the EAdi signal after extubation may show the risks of reintubation or intervention of noninvasive mechanical ventilation.