A nurse is preparing to administer a vaccine to a 4-year-old child. Which of the following vaccines should the nurse administer?

Choice A reason: Improved hydration is not a specific indicator of the effectiveness of the treatment for acute laryngotracheobronchitis. Hydration status should be monitored for any child with a respiratory infection, but it does not reflect the severity of the airway inflammation.

Choice B reason: Decreased temperature is not a specific indicator of the effectiveness of the treatment for acute laryngotracheobronchitis. Fever may or may not be present in this condition, and it does not correlate with the degree of airway obstruction.

Choice C reason: Decreased stridor is a specific indicator of the effectiveness of the treatment for acute laryngotracheobronchitis. Stridor is a high-pitched sound caused by turbulent airflow through a narrowed upper airway. It indicates a significant obstruction that can compromise breathing. A reduction in stridor means that the airway inflammation has subsided and the child can breathe more easily.

Choice D reason: Barking cough is not a specific indicator of the effectiveness of the treatment for acute laryngotracheobronchitis. Barking cough is a characteristic symptom of this condition, caused by the swelling of the vocal cords. It may persist for several days after the acute episode, even when the child is improving.

Choice A reason: Using a 20 gauge needle is not the best action, as it is too large for a preschooler's deltoid muscle. A 20 gauge needle has a diameter of 0.9 mm, which may cause more pain and tissue damage. A smaller gauge needle, such as a 23 or 25 gauge, is recommended for intramuscular injections in children.

Choice B reason: Inserting the needle just below the acromion process is not the best action, as it may not reach the deltoid muscle. The acromion process is the bony prominence at the top of the shoulder. The deltoid muscle is located on the lateral aspect of the upper arm, about two finger widths below the acromion process. The nurse should palpate the acromion process and measure the distance to the injection site.

Choice C reason: Inserting the needle at a 15 degree angle is not the best action, as it may not penetrate the muscle tissue. A 15 degree angle is used for intradermal injections, which are given into the dermis, the layer of skin below the epidermis. Intramuscular injections are given into the muscle tissue, which requires a 90 degree angle. The nurse should hold the syringe perpendicular to the skin and insert the needle quickly and firmly.

Choice D reason: Using a 1.8 mm (0.5 in) needle is the best action, as it is the appropriate length for a preschooler's deltoid muscle. The length of the needle should be based on the child's age, weight, and muscle mass. A 1.8 mm (0.5 in) needle is suitable for children who weigh less than 12 kg (26 lb). A longer needle, such as a 2.5 mm (1 in) needle, may be used for children who weigh more than 12 kg (26 lb).