A client arrives at the ER exhibiting right-sided weakness and expressive aphasia of one hour duration. Several exams are ordered by the physician. Which exam should the nurse make sure is done first? A. CT scan B. CBC C. Chest X-ray D. Carotid Doppler study

First, let's understand the symptoms of the patient. Right-sided weakness indicates a potential issue with the left side of the brain, as the right side of the body is controlled by the left hemisphere. Expressive aphasia means the patient has difficulty speaking or forming words coherently, which is also typically governed by the left side of the brain.

Next, let's briefly go over the different exams and their significance: A. CT scan: A computerized tomography scan provides detailed images of the brain and can quickly detect signs of a stroke or other abnormalities that could cause the patient's symptoms. B. CBC: A complete blood count evaluates the number of blood cells and can help diagnose various disorders, though it may not directly diagnose the cause of the patient's symptoms. C. Chest X-ray: A chest X-ray can reveal lung or heart issues, but it is not the best exam to diagnose the cause of right-sided weakness and expressive aphasia. D. Carotid Doppler study: This noninvasive ultrasound exam measures the blood flow in the carotid arteries and can detect stenosis or blockage, but it is not as rapid of an exam as a CT scan and might not pinpoint an immediate issue in the brain.

Given the patient's symptoms and the relevance of the exams, it is crucial to determine which exam should be conducted first for the most efficient diagnosis and treatment. In this case, a CT scan is the most relevant and urgent exam because it can detect a potential stroke that might be causing the right-sided weakness and expressive aphasia.

Based on our analysis, the most critical exam to be conducted first in this situation is the CT scan. Therefore, the correct answer is: A. CT scan