Final answer:
To diagnose pulmonary embolism in a patient with symptoms, a D-dimer test is conducted first, followed by a CT pulmonary angiogram if the D-dimer is positive, providing a detailed look at the pulmonary arteries.
Step-by-step explanation:
The most appropriate next step in the diagnosis of pulmonary embolism in a 49-year-old woman presenting with chest pain and shortness of breath, after an ECG and chest X-ray, would be the administration of a D-dimer test. If the D-dimer test results are positive, suggesting an increased likelihood of blood clots, a CT pulmonary angiogram should follow. This imaging test provides a detailed look at the blood vessels in the lungs to confirm the presence of a pulmonary embolism. The D-dimer test is a blood test that measures the presence of fibrin degradation products in the blood, which can indicate that clotting has occurred. A CT pulmonary angiogram is a highly sensitive test for detecting blood clots in the pulmonary arteries.
It is important to accurately diagnose a pulmonary embolism due to its potentially serious consequences, which include disruption of pulmonary circulation, lung damage, and even instant death. When a deep vein thrombosis (DVT) occurs, as described in Figure 17.8.2, the risks are significant because of the potential for a clot to travel to and block a pulmonary artery.