Effect of prone or spine position on mechanically ventilated neonates after cardiac surgery with acute lung injury

Abstract

To compare the efficacy and safety ventilated with pressure support ventilation (PSV) or neurally adjusted ventilatory assist (NAVA) in neonates undergoing open-heart surgery with acute lung injury (ALI) in spine and prone positions. Fifteen neonates with a mean age of (15 +/- 9) days and a mean weight of (3.5 +/- 0.6) kg underwent open-heart surgery with ALI from July to December in 2009 were enrolled in this study. After hemodynamic stabilization ventilated with pressure regulated volume control (PRVC-base), all cases were ventilated with PSV and NAVA both in spine (SP) and prone (PP) positions for 60 minutes in a randomized crossover trial respectively. The hemodynamics, blood gas analysis, airway pressure, electrical activity of diaphragm (EAdi) and asynchrony index (AI) during every mode were recorded. The heart rate, systolic blood pressure and central venous pressure were stable in every mode. The peak inspiratory pressure and mean airway pressure in every mode had no significant difference but were significantly lower than in PRVC-base either in spine or prone position. The respiratory rate in PSV and NAVA with prone position was more rapid than in spine position and in PRVC-base (P < 0.05). But there was no significant difference in minute ventilation (MV) for each mode. The oxygenation index was higher in NAVA or PSV in both positions versus PRVC-base [(200 +/- 60) mm Hg in PRVC-base, (272 +/- 76) mm Hg in PSV-SP, (308 +/- 90) mm Hg in PSV-PP, (347 +/- 84) mm Hg in NAVA-SP and (365 +/- 87) mm Hg in NAVA-PP respectively, P < 0.01]. The oxygenation index was significantly higher in NAVA-PP than in PSV-SP (P < 0.05) while PaCO(2) was in normal range and had no significant difference for any mode. The minimal EAdi in NAVA-PP was significant lower than that in PSV-SP [(0.2 +/- 0.1) microV vs (0.5 +/- 0.2) microV, P < 0.05]. The AI of NAVA either in spine or in prone position was 0. It was significantly lower than that in PSV-SP [(21.5 +/- 4.8)%, P < 0.01] and PSV-PP [(22.4 +/- 3.4)%, P < 0.01]. Especially in a prone position, NAVA demonstrates a better synchrony in ALI neonates after cardiac surgery. It helps to provide a better oxygenation for the patients.