A nurse is caring for a client who is febrile. To reduce the client's fever, the nurse applies a cooling blanket. Which of the following findings indicates the client is having an adverse reaction to the cooling?

Rationale: A. Shivering is an adverse reaction to external cooling measures such as a cooling blanket. It indicates that the client’s body is responding to the rapid decrease in temperature by generating heat through muscle activity. This response increases oxygen consumption and metabolic demand, which can counteract the goal of reducing fever and may place additional stress on the cardiovascular system. B. Flushing is more commonly associated with fever itself, vasodilation, or inflammatory processes. It is not a typical adverse reaction to cooling therapy and does not indicate an inappropriate response to the cooling blanket. C. Tachycardia may occur with fever, pain, dehydration, or anxiety. While temperature changes can influence heart rate, tachycardia alone is not a specific adverse reaction to cooling therapy. It is not the most direct indicator of intolerance to cooling. D. Restlessness can be caused by fever, discomfort, hypoxia, or anxiety. Although it may be seen in clients experiencing shivering or discomfort from cooling, it is nonspecific and not the best indicator of an adverse reaction to the cooling blanket compared to shivering.