Diaphragm Ultrasonography Reveals Progressive Changes in Diaphragmatic Function, Morphology, and Muscle Trophism During Invasive Mechanical Ventilation in Children

BACKGROUND: This study aimed to evaluate diaphragmatic muscle behavior via ultrasound in children over the course of invasive mechanical ventilation in a PICU. METHODS: An observational, longitudinal, quantitative study was conducted in a PICU, including children on IMV for more than 48 h. Ultrasound assessments were performed on the first, third, and seventh days of IMV. Measurements included inspiratory and expiratory diaphragmatic thickness, thickening fraction, diaphragmatic excursion, and diaphragmatic slope. RESULTS: A significant reduction in inspiratory thickness (Tdi), expiratory thickness (TDe), and diaphragmatic excursion (DE) was observed over the IMV period (p < 0.001), while the diaphragmatic thickening fraction (DTF) showed a progressive increase (p < 0.001). The diaphragmatic slope showed a downward trend, though not statistically significant (p = 0.06). Patients who received neuromuscular blocking agents (NMBA) exhibited lower DTF values, with a strong correlation (r = 0.79; p < 0.01). CONCLUSION: Diaphragmatic ultrasound demonstrated the ability to detect morphofunctional changes in the diaphragm during IMV in children throughout their PICU stay. The observed changes-particularly in diaphragmatic thickness, excursion, and thickening fraction associated with the use of NMBAs-reinforce the potential of ultrasound as a monitoring tool.