Correct Answer: C

Rationale: The priority nursing action after a corrective surgery for hypertrophic pyloric stenosis (HPS) is to assess the IV site for infiltration. This is crucial to ensure proper fluid administration and prevent complications such as extravasation or infiltration. Applying restraints (Choice A) is not indicated in this scenario and can compromise the infant's comfort and safety. Administering a mild sedative (Choice B) is not necessary and should only be done based on specific clinical indications. Attaching the nasogastric tube to wall suction (Choice D) may be important for certain conditions but is not the priority immediately post-surgery; assessing the IV site is more urgent to prevent potential complications related to IV therapy.

Correct Answer: A

Rationale: Epicanthal folds are a distinctive physical feature commonly observed in individuals with Down syndrome. These are horizontal skin folds that cover the inner corners of the eyes. Webbed neck (choice B) is not typically associated with Down syndrome but can be seen in conditions like Turner syndrome. Enlarged head (choice C) is not a characteristic feature of Down syndrome; however, individuals with hydrocephalus may present with this finding. Polydactyly (choice D) is the presence of extra fingers or toes, which is not a typical feature of Down syndrome.

Correct Answer: B

Rationale: A lumbar puncture is performed to obtain a sample of cerebrospinal fluid for analysis. This fluid is then examined for signs of infection, bleeding, or other abnormalities. Measuring the pressure of cerebrospinal fluid is typically done during the procedure itself, but it is not the primary purpose of the lumbar puncture. While a lumbar puncture can indirectly help relieve intracranial pressure by removing excess cerebrospinal fluid, this is not its primary purpose. Assessing the presence of infection in the spinal fluid is part of the analysis that follows the collection of the sample, making it a secondary outcome of the procedure.

Correct Answer: B

Rationale: Intractable vomiting can lead to alkalosis due to loss of stomach acids.

Correct Answer: B

Rationale: The correct answer is B: 'Long-lasting active immunity is conferred.' Tetanus toxoid injection provides long-lasting active immunity by stimulating the body to produce its own antibodies. Choice A is incorrect because tetanus toxoid injection does not provide passive immunity. Choice C is incorrect because the immunity conferred by the vaccine is not natural but artificially induced. Choice D is incorrect as the immunity provided by the tetanus toxoid injection is active, not passive.