Non-invasive neurally adjusted ventilatory assist in preterm infants: a randomised phase II crossover trial.

<bold>Objective: </bold>To compare non-invasive ventilation neurally adjusted ventilatory assist (NIV-NAVA) and non-invasive pressure support (NIV-PS) in preterm infants on patient-ventilator synchrony.<bold>Design: </bold>A randomised phase II crossover trial.<bold>Setting: </bold>Neonatal intensive care units of two tertiary university hospitals in Korea.<bold>Patients: </bold>Preterm infants born <32 weeks.<bold>Intervention: </bold>NIV-NAVA and NIV-PS were applied in random order after ventilator weaning. Data were recorded for sequential 5 min periods after 10 min applications of each mode.<bold>Main Outcome Measures: </bold>The electrical activity of the diaphragm (Edi), ventilator flow and pressure curves were compared to examine the trigger delay (primary outcome) and other parameters of patient-ventilator interaction (secondary outcomes) for each period.<bold>Results: </bold>Fifteen infants completed the protocol. Trigger delay (35.2±8.3 vs 294.6±101.9 ms, p<0.001), ventilator inspiratory time (423.3±87.1 vs 534.0±165.5 ms, p=0.009) and inspiratory time in excess (32.3±8.3% vs 294.6±101.9%, p=0.001) were lower during NIV-NAVA compared with NIV-PS. Maximum Edi (12.6±6.3 vs 16.6±8.7 μV, p=0.003), swing Edi (8.8±4.8 vs 12.2±8.7 μV, p=0.012) and peak inspiratory pressure (12.3±1.5 vs 14.7±2.7 cm H2O, p=0.003) were also lower during NIV-NAVA. The main asynchrony events during NIV-PS were ineffective efforts and autotriggering. All types of asynchronies except double triggering were reduced with NIV-NAVA. Asynchrony index was significantly lower during NIV-NAVA compared with NIV-PS (p<0.001). No significant differences in leakage, expiratory tidal volume or minute ventilation were observed, but the respiratory rate was lower during NIV-PS than during NIV-NAVA.<bold>Conclusions: </bold>NAVA improved patient-ventilator synchrony and diaphragmatic unloading in preterm infants during non-invasive nasal ventilation even in the presence of large air leaks.<bold>Trial Registration Number: </bold>Registered with http://www.clinicaltrials.gov (NCT01877720). [ABSTRACT FROM AUTHOR]