An infant is brought to the emergency department with poor skin turgor, weight loss, irritability, and tachycardia. The nurse analyzes the data to suggest:

Choice A reason: This statement is correct, as asking about the child's contacts over the last three weeks can help the nurse identify the possible source of infection and the risk of transmission. Rubella is a viral infection that spreads through respiratory droplets or direct contact with an infected person. The incubation period of rubella is 14 to 21 days, meaning that the child could have been exposed to the virus up to three weeks before developing symptoms.

Choice B reason: This statement is incorrect, as asking about the child's immunizations is not the most effective way to determine how the child was exposed to the virus. Although immunization can prevent rubella infection, it is not 100% effective, and some children may still get the disease despite being vaccinated. The nurse should also consider other factors, such as the child's medical history, travel history, and exposure to other people with rash or fever.

Choice C reason: This statement is incorrect, as asking about the medications given to the child is not the most effective way to determine how the child was exposed to the virus. Medications can help relieve the symptoms of rubella, such as fever, rash, or joint pain, but they do not affect the transmission or the course of the infection. The nurse should focus on the epidemiological aspects of the disease, such as the mode of transmission, the incubation period, and the contagious period.

Choice D reason: This statement is incorrect, as asking about the onset of the rash is not the most effective way to determine how the child was exposed to the virus. The rash of rubella usually appears 14 to 17 days after exposure, and lasts for about three days. However, the child can be contagious from seven days before to seven days after the rash appears, meaning that the child could have been exposed to the virus up to four weeks before or after the rash. The nurse should ask about the child's contacts during this period, not just the rash.

Choice A reason: Slowing the heart rate does not increase diastolic filling time. Diastolic filling time is the time during which the ventricles are relaxed and filling with blood. Slowing the heart rate would decrease the cardiac output and worsen the heart failure.

Choice B reason: Increasing urine output does decrease pulmonary congestion, but it is not the primary effect of Captopril. Captopril is an angiotensin-converting enzyme (ACE) inhibitor, which blocks the conversion of angiotensin I to angiotensin II, a potent vasoconstrictor. This reduces the blood pressure and the afterload on the heart. Diuretics are the drugs that increase urine output and reduce fluid overload.

Choice C reason: This is the correct choice. Decreasing the afterload means reducing the resistance that the heart has to overcome to pump blood to the body. This lowers the blood pressure and the workload on the heart, which improves the cardiac function and reduces the symptoms of heart failure.

Choice D reason: Increasing serum potassium does not improve cardiac performance. In fact, high levels of potassium can cause cardiac arrhythmias and cardiac arrest. Captopril can cause hyperkalemia (high potassium) as a side effect, which is why patients on this drug need to monitor their potassium levels and avoid potassium supplements or salt substitutes.