A school-aged child is admitted to the hospital with a vaso-occlusive sickle cell crisis. Which measure in the child's care plan should be given priority?

The correct answer is B: Maintaining fluids through an intravenous line. During a vaso-occlusive sickle cell crisis, proper hydration is crucial to prevent further sickling of red blood cells and to improve blood flow. IV fluids help prevent dehydration, improve circulation, and decrease the risk of complications. Encouraging deep breaths (A) may help with pain management but does not address the underlying issue of dehydration. Beginning active range-of-motion exercises (C) could potentially worsen the crisis by increasing pain and tissue damage. Ensuring a protein-rich diet (D) is important for overall health but is not the priority in this acute situation.