Pressure support ventilation, sigh adjunct to pressure support ventilation, and neurally adjusted ventilatory assist in infants after cardiac surgery: A physiologic crossover randomized study

Objectives We sought to compare gas exchange, respiratory mechanics, and asynchronies during pressure support ventilation (PSV), sigh adjunct to PSV (PSV SIGH), and neurally adjusted ventilatory assist (NAVA) in hypoxemic infants after cardiac surgery. Design Prospective, single-center, crossover, randomized physiologic study. Setting Tertiary-care pediatric intensive care unit. Patients Fourteen hypoxemic infants (median age 11.5 days [8.7-74]). Interventions The protocol begins with a 1 hour step of PSV, followed by two consecutive steps in PSV SIGH and NAVA in random order, with a washout period of 30 minutes (PSV) between them. Main Results Three infants presented an irregular Eadi signal because of diaphragmatic paralysis and were excluded from analysis. For the remaining 11 infants, PaO2/FiO(2) and oxygenation index improved in PSV SIGH compared with PSV (P < 0.05) but not in NAVA compared with PSV. PSV SIGH showed increased tidal volumes and lower respiratory rate than PSV (P < 0.05), as well as a significant improvement in compliance with respiratory system indexed to body weight when compared with both PSV and NAVA (P < 0.01). No changes in mean airway pressure was registered among steps. Inspiratory time resulted prolonged for both PSV SIGH and NAVA than PSV (P < 0.05). NAVA showed the higher coefficient of variability in respiratory parameters and a significative decrease in asynchrony index when compared with both PSV and PSV SIGH (P < 0.01). Conclusions The adjunct of one SIGH per minute to PSV improved oxygenation and lung mechanics while NAVA provided the best patient-ventilator synchrony in infants after cardiac surgery.