Final answer:
The nurse should initially elevate the head of the bed to address the client's symptoms indicative of autonomic dysreflexia, and then immediately notify the healthcare provider for further intervention.
Step-by-step explanation:
The nurse should first address the signs of potential autonomic dysreflexia, which may include facial flushing, headache, nausea, and an elevated blood pressure of 220/110 mmHg. In this scenario, the client is quadriplegic due to a cervical fracture at the C5 level. Given these symptoms, the most appropriate first action is to elevate the head of the bed. This action helps to lower the blood pressure and can alleviate the discomfort. Although the other actions are also important, they do not address the immediate life-threatening situation presented by the high blood pressure.
Once the immediate step is taken to mitigate the blood pressure crisis, the nurse should then notify the healthcare provider immediately regarding the client's condition. Given the urgency of the symptoms, prompt medical intervention is necessary to further evaluate and manage the situation.