Neurally Adjusted Ventilatory Assistance and Synchronized Intermittend Mandatory Ventilation in Children Assessed by Electrical Impedance Segmentography: A Prospective Randomized Case-Control Crossover Trial

Abstract

\n Background: Assessing relative differences of integrated impedance as a surrogate of volume changes between neurally adjusted ventilatory assist (NAVA) and synchronized intermittent mandatory ventilation (SIMV) by using electric impedance segmentography in children.Methods: Performed as a prospective randomized case-control crossover trial in a pediatric intensive care unit of a tertiary center including eight mechanically-ventilated children, four sequences of two different ventilation modes were consecutively applied. The children were randomized in two groups; one that was started on neurally adjusted ventilatory assist and the other on synchronized intermittent mandatory ventilation. During ventilation, electric impedance segmentography measurements were recorded.Results: The relative difference of vertical impedance between both ventilatory modes was measured (median 0.52, IQR 0-0.87). These differences in left apical lung segments were present during the first (median 0.58, IQR 0-0.89, p=0.04) and second crossover (median 0.50, IQR 0-0.88, p=0.05) as well as across total impedance (0.52 IQR 0-0.87; p=0.002). During neurally adjusted ventilatory assist children showed a shift of impedance towards caudal lung segments, compared to synchronized intermittent mandatory ventilation.Conclusion: Electrical impedance segmentography enables dynamic monitoring of transthoracic impedance. Segmental measurements, however, were of low reproducibility due to various limiting factors in its application. For further evaluation, larger prospective clinical trials are necessary.