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. Low-grade fever.' A low-grade fever is a common and mild side effect of the Hib vaccine, indicating that the immune system is responding to the immunization. Lethargy (choice A) can be a sign of more serious adverse effects and should be monitored closely but is not typically associated with the Hib vaccine. Urticaria (choice B) and generalized rash (choice C) are less common side effects of the Hib vaccine compared to low-grade fever.

Correct Answer: B

Rationale: The correct answer is B: Signs of dehydration. Infants with hypertrophic pyloric stenosis (HPS) are at high risk of dehydration due to frequent vomiting. Assessing for signs of dehydration, such as decreased urine output, dry mucous membranes, and sunken fontanelles, is crucial for early intervention and management. Choices A, C, and D are not the most critical assessments for HPS. The quality of the cry (choice A) may not provide as much relevant information in this case. Coughing up of feedings (choice C) may be a symptom but is not as crucial as assessing for dehydration. Characteristics of the stool (choice D) are important but assessing for signs of dehydration takes precedence due to the immediate risk it poses to the infant's health.

Correct Answer: B

Rationale: For a child with a disorder of the posterior pituitary gland, desmopressin acetate is a medication commonly used to manage the condition by replacing the antidiuretic hormone. Instructing the parents on how to administer desmopressin acetate correctly is essential for the child's care. Choice A is incorrect because growth hormone treatment is not typically used for posterior pituitary disorders. Choice C is incorrect as treatment for this condition usually continues beyond puberty. Choice D is incorrect as acute adrenal crisis is not directly related to a disorder of the posterior pituitary gland.

Correct Answer: A

Rationale: The correct answer is A: Incisors. In infants, incisors are usually the first teeth to erupt, typically around 6 months of age. These are the front teeth used for cutting food. Canines (Choice B), upper molars (Choice C), and lower molars (Choice D) typically erupt after the incisors. Canines are sharp teeth used for tearing food, while molars are flat teeth used for grinding food.