Ultrasound Assessment of Ventilator-induced Diaphragmatic Dysfunction in Paediatrics

Abstract

Introduction: Invasive mechanical ventilation contributes to ventilator-induced diaphragmatic dysfunction, delaying extubation and increasing mortality in adults. Despite the possibility of having a higher impact in paediatrics, this dysfunction is not routinely monitored. Diaphragm ultrasound has been proposed as a safe and non-invasive technique for this purpose. The aim of this study was to describe the evolution of diaphragmatic morphology and functional measurements by ultrasound in ventilated children.
Material and Methods: Prospective exploratory study. Children admitted to Paediatric Intensive Care Unit requiring mechanical ventilation > 48 hours were included. The diaphragmatic thickness, excursion and the thickening fraction were assessed by ultrasound.
Results: Seventeen cases were included, with a median age of 42 months. Ten were male, seven had comorbidities and three in seventeen had malnutrition at admission. The median time under mechanical ventilation was seven days. The median of the initial and minimum diaphragmatic thickness was 2.3 mm and 1.9 mm, respectively, with a median decrease in thickness of 13% under pressure-regulated volume control. Diaphragmatic atrophy was observed in 14/17 cases. Differences in the median thickness variation were found between patients with sepsis and without (0.70 vs 0.25 mm; p = 0.019). During pressure support ventilation there was a tendency to increase diaphragmatic thickness and excursion. Extubation failure occurred for diaphragmatic thickening fraction ≤ 35%.
Discussion: Under pressure-regulated volume control there was a tendency for a decrease in diaphragmatic thickness. In the pre-extubation stage under pressure support, there was a tendency for it to increase. These results suggest that, by titrating ventilation using physiological levels of inspiratory effort, we can reduce the diaphragmatic morphological changes associated with ventilation.
Conclusion: The early recognition of diaphragmatic changes may encourage a targeted approach, namely titration of ventilation, in order to reduce ventilator-induced diaphragmatic dysfunction and its clinical repercussions.