Final answer:
Using a defibrillator is the least appropriate intervention for a 4-year-old boy with a broken arm and an infected laceration who has an elevated heart rate. Managing fever with antipyretics, administering analgesics for pain, and comforting the child are appropriate measures. Hypothermia is used in specific clinical settings and is not applicable for routine care of an elevated heart rate. The correct option is B.
Step-by-step explanation:
In addressing the scenario of a 4-year-old boy with a broken arm and an infected laceration, the most important consideration is to assess and manage his immediate symptoms. The least appropriate intervention for an elevated heart rate in this context would be using a defibrillator to reduce heart rate.
A defibrillator is a tool used in emergency situations for life-threatening cardiac arrhythmias, not for elevated heart rates due to fever, pain, or the presence of the parents. Appropriate measures would include administering antipyretics to manage fever and administering analgesics to relieve pain. Allowing the parents to comfort the child can also be beneficial, as emotional support can help reduce stress and potentially assist in normalizing the child's heart rate.
Understanding the physiological responses to temperature variations gives insight into the appropriateness of different interventions. Hyperthermia can cause an increase in heart rate, and thus managing fever could help in stabilizing it.
On the other hand, inducing hypothermia is a controlled medical practice used in specific circumstances, such as during open-heart surgery, where potassium chloride (KCl) may be used to stop the heart safely, under carefully managed conditions with the support of a heart-lung machine. This clinical application is vastly different from the symptomatic care of a child with an infection and should not be confused with the routine care of elevated heart rate due to pain or fever.