A Comparison of Two Ventilators Using Volume Guarantee Modes for Ventilation of the Neonate Using a Lung Model

Background: Volume guarantee modes (VG) are used with increasing frequency for the neonatal population in an attempt to minimize lung injury and hypocarbia due to unintentional hyperventilation. Ventilator manufacturers utilize different proximal flow sensor technology and software to achieve VG, and investigation of the behavior of each ventilator is useful. This ex vivo experimental design evaluated the Vti, Vte, and PIP delivered during VG modes with the Vyasis Avea (Avea) and Drager VN500 Babylog (VN500) using the IngMar Medical ASL 5000 electronic lung simulator (ASL 5000). Results: The Avea and VN500 delivered similar volumes and pressures as recorded by the ASL 5000 with less than ± 0.02 standard deviation for each parameter. The Avea demonstrated wider standard deviation due to periodic spikes in Vti and PIP. The VN500 consistently delivered lower tidal volumes as measured by the ASL 5000 compared to the Avea, usually at lower measured PIP. This delta varied with each breath. Conclusions: The VN500 and Avea deliver consistent Vti, Vte, and PIP in a passive model. Measured values higher than set VG on both ventilators, and lower Vti and Vte on the VN500, may be due to variances in how each ventilator deals with the compressible volume of the breathing circuit and temperature and saturation of the inspired gas