Which of the following is a critical step in preventing ventilator-associated pneumonia (VAP)?

Correct Answer: B

Rationale: Elevating the head of the bed to 30-45 degrees is a critical step in preventing ventilator-associated pneumonia (VAP) because it helps reduce the risk of aspiration, which is a significant factor in the development of VAP. Elevating the head of the bed enhances pulmonary hygiene, decreases the risk of microaspiration, and promotes better lung function. Performing oral care with chlorhexidine is essential for oral hygiene but is not specifically aimed at preventing VAP. Administering prophylactic antibiotics without a clear indication can lead to antibiotic resistance and is not a recommended routine practice to prevent VAP. Changing the ventilator circuit daily is essential for infection control but is not the most critical step in preventing VAP.

Correct Answer: B

Rationale: The correct answer is B: Ensuring the tracheostomy ties are secure. This is the nurse's first priority because it is critical to prevent accidental decannulation, which could compromise the patient's airway. Providing humidified oxygen, suctioning the tracheostomy tube, and monitoring for signs of infection are important aspects of care but ensuring the tracheostomy ties' security takes precedence to maintain the patient's airway.

Correct Answer: B

Rationale: The correct answer is B: Airborne isolation. Measles is highly contagious and can be transmitted through airborne particles, so airborne isolation is necessary to prevent its spread. Choice A, Contact isolation, is incorrect because measles is not primarily transmitted through direct contact. Choice C, Droplet isolation, is also incorrect as measles is not transmitted through large droplets but through smaller airborne particles. Choice D, Reverse isolation, is used to protect a patient from outside infections, not to prevent the spread of a contagious disease like measles.

Correct Answer: A

Rationale: The correct answer is A: B lymphocytes. B lymphocytes (B cells) are a crucial part of the adaptive immune system. They produce antibodies, which are proteins that specifically target and neutralize pathogens such as bacteria and viruses. T lymphocytes (choice B) are involved in cell-mediated immunity rather than antibody production. Macrophages (choice C) are phagocytic cells that engulf and digest pathogens but do not produce antibodies. Neutrophils (choice D) are a type of white blood cell that primarily function in the innate immune response by phagocytosing pathogens.

Correct Answer: A

Rationale: The olfactory nerve (Cranial Nerve I) is indeed responsible for the sense of smell. It is located in the nasal cavity and transmits olfactory information to the brain. The optic nerve (Choice B) is responsible for vision, the trigeminal nerve (Choice C) is responsible for sensation in the face, and the vagus nerve (Choice D) is responsible for various functions such as heart rate, digestion, and speech. Therefore, the correct answer is the olfactory nerve (Choice A).