Correct Answer: B

Rationale: Administering the scheduled dose is appropriate in this scenario since the heart rate of 128 bpm is within an acceptable range for a 2-year-old child with heart failure. Monitoring for signs of digoxin toxicity is important; however, the immediate action required is to administer the scheduled dose as prescribed based on the heart rate assessment.

Correct Answer: A

Rationale: The first step in developing a behavior modification program for an extremely aggressive 10-year-old boy is to identify what activities, foods, and toys the child enjoys. Understanding the child's motivations is crucial in creating an effective behavior modification plan tailored to his interests and preferences, which can help in positively reinforcing desired behaviors.

Correct Answer: C

Rationale: In clients with bulimia nervosa, electrolyte imbalances are common due to purging behaviors and can lead to severe complications. Monitoring electrolyte levels is essential to detect and manage any imbalances promptly, as they can be life-threatening.

Correct Answer: C

Rationale: Using a barrier cream like zinc oxide forms a protective layer on the skin, creating a barrier against irritants and moisture, thus helping to prevent diaper rash. Unlike other options, barrier creams do not need to be completely removed at each diaper change, allowing the skin to remain protected between changes.

Correct Answer: D

Rationale: The presence of swollen red spots and fluid-filled blisters may indicate a contagious condition. Implementing transmission precautions is crucial to prevent the spread of the infection to others in the clinic setting.