Correct Answer: B

Rationale: The correct answer is the sweat chloride test. This test is crucial in diagnosing cystic fibrosis as it measures the amount of chloride in sweat, which is typically elevated in individuals with cystic fibrosis. A chest X-ray (Choice A) may show characteristic findings like hyperinflation or bronchiectasis, but it is not a definitive diagnostic test for cystic fibrosis. Pulmonary function tests (Choice C) may help assess lung function but are not specific for cystic fibrosis. Sputum culture (Choice D) may be used to identify specific pathogens causing respiratory infections but is not a primary diagnostic test for cystic fibrosis.

Correct Answer: B

Rationale: The correct answer is B: Steroids. Children receiving steroids should not receive the varicella vaccine as it can increase the risk of severe infection due to the immunosuppressive effects of steroids. Insulin (Choice A) is not a medication that contraindicates varicella vaccination. Antibiotics (Choice C) and anticonvulsants (Choice D) are also not medications that would impact the decision to immunize against varicella.

Correct Answer: A

Rationale: The correct answer is A: Administering chemotherapy. In the care of a child with acute lymphoblastic leukemia (ALL), the priority nursing intervention is administering chemotherapy. Chemotherapy is the primary treatment for ALL and plays a crucial role in managing the disease. While preventing infection, monitoring for signs of bleeding, and providing nutritional support are important aspects of caring for a child with ALL, administering chemotherapy takes precedence as it directly targets the cancer cells and aims to induce remission.

Correct Answer: A

Rationale: The nurse should suspect measles based on the symptoms described, including the presence of Koplik spots (small, red spots with blue-white centers in the mouth). Measles typically presents with fever, irritability, runny nose, and a rash that begins on the face and spreads downward. Chickenpox (choice B) presents with vesicular lesions in different stages of healing and usually starts on the trunk. Fifth disease (choice C) presents with a 'slapped cheek' rash on the face and can cause joint pain. Scarlet fever (choice D) is characterized by a sandpaper-like rash, fever, and strawberry tongue.

Correct Answer: B

Rationale: The most important factor in preparing a toddler for additional surgery is their previous experience of hospitalization. This familiarity can help reduce anxiety and fear associated with the hospital environment and medical procedures. Choice A, satisfying the child's wishes, may not always be feasible or in the child's best interest during medical procedures. Choice C, preventing the child from being with strangers, may not address the core issue of preparing the child for surgery. Choice D, ensuring the child still receives parental affection, is important but may not directly address the preparation needed for surgery.