What major complication should be monitored in a child with prolonged respiratory distress?

In the context of prolonged respiratory distress in a child, hypoxemia, or low levels of oxygen in the blood, is a critical complication to monitor. This condition can arise when the lungs are unable to effectively exchange oxygen and carbon dioxide, leading to insufficient oxygenation of the body's tissues. In situations of respiratory distress, the airway may be compromised, or the respiratory muscles may become fatigued, preventing the child from ventilating adequately.

Monitoring for hypoxemia is essential, as it can quickly progress to more severe complications such as respiratory failure, which may necessitate urgent medical intervention. Symptoms of hypoxemia can include cyanosis, increased work of breathing, altered mental status, and lethargy, all of which indicate that a child's oxygen levels are dangerously low.

While hypertension, dehydration, and gastroesophageal reflux are important considerations in pediatric care, they are not direct or immediate consequences of prolonged respiratory distress. Hypertension can occur due to other medical conditions or stress responses, dehydration typically develops from persistent fluid loss or inadequate intake, and gastroesophageal reflux is more related to gastrointestinal issues rather than a direct result of respiratory problems. Therefore, hypoxemia is the primary complication that should be closely monitored in this scenario.