Introduction
Invasive mechanical ventilation (IMV) with positive pressure is
widespread in pediatric intensive care units (PICUs), with at least
one-third of children being mechanically
ventilated.1,2. Prolonged IMV is associated with
ventilator-related injury, increased nosocomial infection risk, longer
sedation requirement3 and diaphragmatic atrophy4. Ultimately, children should be weaned from the
ventilator once the clinical condition improves. However, the optimal
timing of extubation is not easy to determine, considering both early
and late extubation may affect clinical outcomes. Extubation failure is
associated with poorer clinical outcomes in children, with a reported
rate of 2.7 percent to 22%.3,5,6. Children’s weaning
practices vary depending on hospitals, staff, and resources. Therefore,
predictive indicators of successful extubation are needed. Several
indices have been developed to predict weaning success and extubation
failure, including the Rapid Shallow Breathing Index (RSBI = f/Vt);
Maximal Inspiratory Pressure (MIP), Compliance Resistance Oxygenation
Pressure Index (CROP); Volumetric Capnography; and Extubation Readiness
Test7 (ERT). However, none of the above indices have
been widely used in PICU practice except ERT8–10.
Due to the suppression of inspiratory effort, diaphragmatic atrophy
occurs quickly in mechanically ventilated children, resulting in
ventilator induced diaphragmatic dysfunction (VIDD), which is related to
difficulties weaning from IMV, prolonged duration of stay, and other
complications4,11,12. Additionally, high ventilator
mandatory breathing rates, corticosteroids, and neuromuscular blockers
aggravate VIDD13.
With the extensive use of ultrasound in critical care settings,
detecting VIDD and predicting weaning outcomes using ultrasonographic
diaphragm imaging have been clinical research hotspots in recent years.
Several adult studies demonstrated that some structural indexes such as
excursion, thickness and thickening fraction of diaphragm obtained with
the point of care diaphragm ultrasound (DUS) have good predictive values
on successful extubation14,15. Although various
research has demonstrated that DUS may be used to examine children’s
diaphragm functions16 and predict extubation
failure17,18, there is a dearth of evidence regarding
its use in weaning procedures.
This study aims to evaluate the predictive value of DUS in weaning
outcomes in mechanically ventilated children and develop a more reliable
tool for its use in pediatric intensive care units.