RESUMO
BACKGROUND: Apnea time allows the clinician to set a minimum spontaneous respiratory frequency when using noninvasive neurally-adjusted ventilatory assist (NIV-NAVA). Short apnea times may provide backup ventilation during periods of physiologic variability causing overventilation and suppression of spontaneous respiratory drive. Longer apnea times may allow more spontaneous ventilation but can result in insufficient respiratory support. The purpose of this study was to evaluate various apnea times in neonates on NIV-NAVA. METHODS: This was a 2-center, prospective, 1-factorial, interventional study of neonates <30 weeks gestational age on NIV-NAVA. Clinically important events and ventilator data were recorded for apnea times of 2 s and 5 s for 2 h each. RESULTS: 15 neonates (26 ± 1.6 weeks gestational age, birthweight 893 ± 202 g) were studied. When compared to the 5-s apnea time, the 2-s apnea time showed increased switches into backup ventilation from 0.5 switches/min to 2.5 switches/min (P < .001), and time spent in backup ventilation increased from 2%/min to 9%/min (P < .001). However, clinically important events decreased from 7 clinically important events per hour to 2 clinically important events per hour (P < .001). Measured breathing frequency increased with the 2-s apnea time but spontaneous breathing frequency, FIO2 , peak and minimum electrical activity of the diaphragm, and peak pressure remained unchanged. CONCLUSION: Short apnea times resulted in more switches into backup ventilation and longer time in backup ventilation but promoted clinical stability with fewer clinically important events in neonates ventilated with NIV-NAVA.