Lower back-up rates improve ventilator triggering during assist-control ventilation: a randomized crossover trial

The objective of this study is to compare the effects of back-up ventilation rates (BURs) on triggered inflations and patient cardiorespiratory stability during assist-control/volume guarantee ventilation (AC/VG). STUDY DESIGN: This study is a randomized crossover trial conducted in a neonatal unit in an Australian tertiary NICU. In all, 26 stable preterm infants on AC/VG ventilation were studied at BUR settings of 30, 40 and 50 min(-1). Inflation rate, triggering and cardiorespiratory measures of patient stability were compared during 20 min epochs with 10 min washout periods. RESULT: The 26 infants studied were median (inter-quartile range) gestational age 27 (26, 30) weeks, birth weight 0.84 (0.75, 1.14) kg and FiO(2) 0.24 (0.21, 0.31) and age 6 (4, 19) days. At BURs of 30, 40 and 50, the proportions of inflations, which were triggered, were mean (s.d.) 85 (11), 75 (19) and 61 (25); P