Nurse Bryan knows that the age group that uses the most units of blood and blood products is:

Correct Answer: A

Rationale: Premature infants, especially those born very premature or with health complications, often require blood transfusions due to their underdeveloped organs and medical conditions. Their small size and medical fragility make them the age group that typically uses the most units of blood and blood products. This high demand for blood products is necessary to support their growth, development, and overall health. Conversely, while individuals in other age groups may also require blood transfusions, premature infants have specific and ongoing needs that often result in a greater overall use of blood and blood products in this age group.

Correct Answer: C

Rationale: Iron is classified as an Antianemic agent. Anemia is a condition characterized by a lack of healthy red blood cells, which are responsible for carrying oxygen to the body's tissues. Iron is essential for the production of hemoglobin, the protein in red blood cells that binds oxygen. Therefore, iron supplements are commonly used to treat iron-deficiency anemia by replenishing the body's iron stores and supporting the production of healthy red blood cells.

Correct Answer: A

Rationale: Atropine given via intramuscular (IM) injection typically reaches its peak effects within 15 to 50 minutes after administration. The onset of action is relatively rapid, with faster absorption and distribution compared to oral administration. The effects of atropine can be seen within minutes, reaching peak concentration within the specified time frame. This rapid onset is important clinically when atropine is used to treat conditions such as bradycardia or nerve agent poisoning where a quick response is needed.

Correct Answer: A

Rationale: The concentration of a drug in the blood decreases by half with each half-life. Thus, after 4 to 5 half-lives, the amount of drug remaining in the blood would be approximately 6.25% to 3.125% of the original concentration. This translates to the concentration being around 50% or less, making the correct answer A. 50%.

Correct Answer: D

Rationale: Reye's syndrome is a rare but serious disorder that primarily affects children and teenagers. It is characterized by an acute encephalopathic illness along with fatty degeneration of the liver and other viscera. Reye's syndrome typically arises after a viral infection, such as influenza or chickenpox, rather than being enhanced by sodium and water retention. This condition is not caused by excessive sodium and water retention but rather by a possible link to the use of aspirin during viral infections in children.