Correct Answer: B

Rationale: During a vaso-occlusive crisis in sickle cell anemia, ensuring adequate hydration is crucial because it helps to reduce the viscosity of the blood and prevent further sickling of the cells. Administering oxygen may be necessary in some cases to improve tissue oxygenation, but hydration is the priority to prevent complications. Monitoring vital signs is important, but hydration takes precedence during a vaso-occlusive crisis. Administering pain medication is important for pain management but does not address the underlying issue of vaso-occlusion.

Correct Answer: A

Rationale: The correct answer is A: 'Mental retardation occurs if PKU is untreated.' Phenylketonuria (PKU) is a metabolic disorder that results in the inability to metabolize phenylalanine properly. Without proper dietary management, high levels of phenylalanine can lead to severe mental retardation and other neurological problems. Therefore, educating parents about the importance of early and consistent treatment to prevent mental retardation is crucial. Choice B is incorrect because testing for PKU is typically done shortly after birth, not immediately. Choice C is incorrect because treatment for PKU primarily involves strict dietary management to control phenylalanine intake, not lifelong medications. Choice D is incorrect because PKU is inherited in an autosomal recessive pattern, not as an autosomal dominant gene.

Correct Answer: B

Rationale: The most important factor in preparing a toddler for additional surgery is their previous hospitalization experience. This familiarity with the hospital setting and procedures can help reduce anxiety and fear in the child. Choice A, meeting the child's wishes, may not always align with what is medically necessary or safe for the child. Choice C, preventing the child from staying with strangers, is important for general comfort but may not directly address the child's preparation for surgery. Choice D, ensuring ongoing parental affection, is crucial for emotional support but may not have the same impact as the child's previous hospitalization experience in preparing them for the surgery.

Correct Answer: C

Rationale: The correct answer is to maintain standard and contact precautions. RSV is highly contagious, primarily spreading through respiratory secretions. Therefore, it is crucial to implement infection control measures to prevent the spread of the virus within the healthcare setting. Option A is incorrect as warmth and dryness are not the primary concern in RSV management. While family support is important, allowing visits may increase the risk of spreading the infection, making option B less appropriate. Option D is incorrect because RSV is a viral infection, and antibiotics are not effective against viruses.

Correct Answer: D

Rationale: While catheterization can be uncomfortable, it does not typically result in long-term psychological harm, and obtaining a sterile specimen is important for accurate diagnosis.