This test places exercise demands on the heart and can uncover CAD not detected with an ECG. Many patients with diabetes have additional risk factors for CAD, such as obesity, hypertension, and abnormal blood lipid levels. Thus, a physician may have a patient undergo an exercise stress test even if her ECG is normal.

A stress test can also be used to monitor the progression of CAD. A patient may require periodic stress tests, especially if new symptoms of CAD appear or new risk factors are identified.

Nursing Considerations

Review your patient’s drug history and find out from her physician which drugs should be with­held and which she should take on the day of the stress test. A physician may withhold oral antidiabetic drugs because exercise lowers blood glucose levels. If your patient uses insulin, her physician may prescribe a lower dose to avoid hypoglycemia during the test.

Instruct your patient to rest the day before the test so that she has the energy to perform it. She should also fast for at least 3 hours and avoid smoking for at least 1 hour before the test. Explain to your patient what she can expect during the test and what she should wear. This information may ease her anxiety.

Determine if your patient has autonomic neuropathy, which affects involuntary functions, such as heart rate and blood pressure. During stress testing, patients with such neuropathy may not experience chest pain even though ischemia develops. Also, the blood pressure may go very high or very low when exercising. If your patient has autonomic neuropathy, closely monitor her throughout the test. The physician may even decide that an exercise stress test is inappropriate for such a patient and substitute a dipyridamole­thallium test. With this test, dipyridamole, instead of exercise, is used to put stress on the heart. The thallium acts as a contrast agent.