A nurse is caring for a patient who is receiving mechanical ventilation. Which of the following actions should the nurse take to prevent ventilator-associated pneumonia? Which action prevents ventilator-associated pneumonia?

The correct answer is B: Keep the head of the bed elevated to 30-45 degrees. Elevating the head of the bed helps prevent aspiration, which is a significant risk factor for ventilator-associated pneumonia. This position promotes proper lung expansion and drainage of secretions, reducing the likelihood of bacterial growth in the lungs. Performing oral care every 12 hours (A) is important for oral hygiene but does not directly prevent ventilator-associated pneumonia. Administering antibiotics prophylactically (C) can lead to antibiotic resistance and is not recommended routinely. Changing the ventilator circuit daily (D) is important for infection control but does not directly prevent ventilator-associated pneumonia.