Can a simple heart ultrasound prevent fluid overload in kids after surgery?

This study looks at whether a quick ultrasound of the heart can help doctors decide how much fluid to give children after major surgery. Giving too much fluid can be harmful, but there aren't good tools to guide this in kids. The researchers will measure blood flow changes in the aorta using a special ultrasound probe placed on the chest. The goal is to see if this method can predict which children need more fluids, helping to avoid complications.