Final answer:
The nurse should administer an antipyretic medication to address the fever, as it may help reduce the child's distress and decrease the heart rate. Managing the fever is the immediate priority over options like sedatives or bronchodilators, which are not first-line treatments for croup and carry risks.
Step-by-step explanation:
The nurse should administer an antipyretic medication.
The 21-month-old child's increased respiratory rate of 48 breaths per minute is elevated compared to the normal rate for their age, but is not necessarily alarming, as stress and fever can contribute to a higher respiratory rate. Croup is a condition characterized by inflammation around the vocal cords, leading to a characteristic barking cough and can cause difficulty breathing. The child's heart rate of 120 bpm is mildly elevated, likely due to the fever and respiratory effort. Temperature management is crucial as fever can exacerbate respiratory symptoms in children.
It's important to note that while a cool mist humidifier might ease respiratory discomfort by moistening and soothing irritated airways, the immediate priority in this context is to reduce the child's fever, which is contributing to their distress and increased heart rate. Cooler ambient temperatures by using a humidifier might help, but directly addressing the fever with an antipyretic medication like acetaminophen or ibuprofen is the recommended next step to provide comfort and potentially ease the work of breathing. Sedatives and bronchodilators are not the first-line treatments in this scenario and carry risks especially if used without an appropriate indication and monitoring.