Correct Answer: D

Rationale: The most accurate way to determine a therapeutic dose for children is based on their weight rather than age. Weight-based dosing accounts for individual variations in drug metabolism and distribution, ensuring a more precise and safer medication administration. Choices A, B, and C are incorrect as they do not address the importance of weight-based dosing in children, potentially leading to inappropriate dosing and safety concerns.

Correct Answer: D

Rationale: Surgical repair of patent ductus arteriosus (PDA) aims to prevent increased pulmonary vascular congestion, which can lead to congestive heart failure and respiratory distress. Choice A, pulmonary infection, is not a direct complication of PDA but rather a result of other factors. Choice B, right-to-left shunt of blood, is a characteristic of a different heart condition (e.g., Tetralogy of Fallot) and not specifically associated with PDA. Choice C, decreased workload on the left side of the heart, is not a typical complication of PDA but rather a consequence of left-to-right shunting that can cause volume overload in the pulmonary circulation.

Correct Answer: B

Rationale: The correct technique for opening the airway of an infant with no suspected neck injury is to tilt the head back without hyperextending the neck. This method helps to keep the airway open without risking injury to the infant's delicate neck structures. Choice A, lifting up the chin and hyperextending the neck, can potentially harm the infant's neck. Choice C, gently lifting the chin while maintaining slight flexion of the neck, is not as effective as tilting the head back. Choice D is incorrect as infants require a different approach compared to older children or adults due to their anatomical differences.

Correct Answer: D

Rationale: The correct answer is D: Serum immunoglobulin E (IgE) level. An elevated serum IgE level is commonly associated with atopic dermatitis, reflecting an allergic response. Choice A, erythrocyte sedimentation rate, is a nonspecific test for inflammation and not specific to atopic dermatitis. Choice B, potassium hydroxide prep, is used to diagnose fungal infections like tinea versicolor, not atopic dermatitis. Choice C, wound culture, is not typically indicated for the diagnosis of atopic dermatitis as it is a chronic inflammatory skin condition rather than an infectious process.

Correct Answer: A

Rationale: When assessing a 2-year-old child with abdominal pain and adequate perfusion, it is essential to examine the child in the parent's arms. This approach helps reduce anxiety, provide comfort, and establish trust with the child. Palpating the painful area of the abdomen first (Choice B) may cause discomfort and increase anxiety in the child. Placing the child supine and palpating the abdomen (Choice C) without considering the child's comfort and security may lead to resistance and inaccurate assessment. Separating the child from the parent (Choice D) can exacerbate the child's anxiety and hinder the examination process. Therefore, examining the child in the parent's arms is the most appropriate approach in this scenario.