Anesthesia workstation performance in pediatric ventilation – Part 1: Precision of ventilation.

BACKGROUND: Mechanical ventilation of children sets the highest demands on the performance of anesthesia workstations. Different ventilator technologies are available, each representing unique pneumatic characteristics. We hypothesized that precision of delivered ventilation parameters depends on the ventilator type. METHODS: Six modern anesthesia workstations (GE HealthCare Carestation 650; Mindray Bio-Medical Electronics Co. Ltd. Wato EX-65 Pro and A9; Dräger Medical Atlan A350 and Perseus A500; Getinge Flow-c) were tested in physical models simulating the respiratory systems of a preterm baby, a neonate, an infant and a toddler. Volume-controlled and pressure-controlled ventilation were investigated with and without airway leakage. Delivered tidal volume, peak inspiratory pressure, positive end-expiratory pressure and inspiratory to expiratory ratio were compared to the set values. Data are presented descriptively, a difference ≥ 10 % between delivered and the set values was considered clinically relevant. RESULTS: Deviations of the delivered volume from the set tidal volume during volume-controlled ventilation ranged between -19.5 ± 0.6 % and +35.1 ± 3.0 % in the preterm baby model, but decreased with increasing tidal volume. Positive end-expiratory pressure and peak inspiratory pressure during pressure-controlled ventilation did not differ relevantly from the set values in any device or lung model. Expiratory ratios varied widely in most devices leading to relevant differences in tidal volume during pressure-controlled ventilation. With leakage, tidal volume was on average 7 % lower during volume-controlled ventilation but 2 % lower during pressure-controlled ventilation. CONCLUSIONS: Precision of ventilation with modern anesthesia workstations varies depending on the ventilator type, ventilation mode and the set parameters. Pressure-controlled ventilation is advantageous in the six workstations tested considering the good agreement between the applied and the set parameters and leakage compensation. Our results imply precision superiority of pressure-controlled ventilation over volume-controlled ventilation in preterm babies and neonates, independent from the ventilator technology in use.