Background. Modern anesthesia workstations include various ventilator technologies, but the effects on pediatric ventilation are unclear. We hypothesized that performance during pressure support ventilation and times to increase oxygen concentrations depend on the type of anesthesia workstation. 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 evaluated in respiratory models of a preterm baby, a neonate, an infant and a toddler. Trigger response rates, trigger delay and time to reach 50 % of peak inspiratory pressure during pressure support ventilation were compared. Furthermore, the times required to increase oxygen concentration from 21 to 90 % during pressure-controlled ventilation at fresh gas flows of 1, 3 and 10 l·min -1 were assessed in a compartment of the lung models with the volume corresponding to the respective model’s functional residual capacity. Results. Trigger response rates were above 90 %, with few exceptions. Trigger delays ranged between 73 ± 6 ms and 145 ± 0 ms. Times to reach 50 % peak pressure ranged between 161 ± 1 ms and 312 ± 1 ms, with decreasing variability in the larger patient models. Oxygen rise time varied between 94 ± 3 s and 615 ± 60 s at the lowest fresh gas flow and decreased with increasing fresh gas flow to 3 l·min -1 , and less so with further increasing fresh gas flow to 10 l·min -1 . Activation of oxygen flush did not generally increase oxygen concentration but caused relevant airway pressure increases in some devices. Conclusions. Modern anesthesia workstations show an overall good performance during pressure support ventilation of children. During pressure-controlled ventilation a moderate increase of fresh gas flow accelerated the rise in oxygen concentration, depending on the device. Oxygen flush brings no advantage in this regard but may put the patient at risk of high airway pressure.
Spaeth et al. (Wed,) studied this question.