Abstract Rationale In the last 3 years, several mechanical ventilator models have become available for use in the pediatric population. Our clinical practice suggests these ventilators function differently even when settings are identical across them. The purpose of this study was to determine how varying set pressures and intentional leak levels affect the percent error between measured and ventilator-estimated tidal volumes of three ventilators commonly used in pediatrics (EV300, Vivo45, and V-Pro). Methods This study utilized three different ventilators commonly used in the pediatric population: the EV300, Vivo45, and V-Pro. We used a 0.5L infant test lung (SmartLung; IMT Analytics AG) and a single-limb, passive circuit (Fischer and Paykel, adult). Exhaled tidal volumes were measured using a flowmeter between the exhalation valve and the test lung. Two different exhalation valves were used to create two different intentional leak conditions. For each ventilator, we analyzed the following four conditions: low pressure with high leak valve, high pressure with high leak valve, low pressure with low leak valve, and high pressure with high leak valve. The estimated exhaled tidal volume reported by each ventilator was compared to the exhaled tidal volume measured by the flowmeter for each condition. A peak inspiratory pressure of 30 cmH2O was used for the high pressure setting and a peak inspiratory pressure of 20 cmH2O was used for low pressure setting. All other settings were held constant with a PEEP of 8 and inspiratory time of 0.7 seconds. Results For the EV300 and Vivo45 ventilators, the percent error between estimated and measured exhaled tidal volume was very low when using a low leak valve at both low pressure (3.1% for EV300 and 0% for Vivo45) and high pressure (2.6% for EV300 and 2% for Vivo45). The percent error increased for both ventilators with transition to a high leak valve (15-36%). In contrast, the V-Pro ventilator had a more significant percent error (19% or greater) under both high and low leak conditions. The percent error was more elevated at high pressure setting (29-36%) than low pressure setting (19-23.7%). CONCLUSIONS Two main conclusions were drawn from this study. First, within the tested parameters, lower leak levels reduce the percent error for ventilator tidal volume estimation in most, but not all, ventilators. Second, at higher pressures, the actual delivered tidal volume varies more from the estimated tidal volumes across different ventilator models. This abstract is funded by: None
Boullt et al. (Fri,) studied this question.