Even though the person you're caring for is out of the ER, serious complications may still arise. An estimated one out of five stroke patients dies during his hospital stay.

The patient's treatment team has two main goals: To prevent another stroke from occurring and to minimize and respond to any complications.

To this end, the person you're caring for will undergo more testing to determine the cause of this stroke. Although the doctors should know what type of stroke he had, they'll still need to pinpoint the exact cause. They may perform one or more of the following tests:

• Carotid ultrasound to determine if either carotid artery is narrowed or blocked. This test is noninvasive and painless: A technician applies jelly to the patient's neck, then slides an ultrasound wand over the skin covering his carotid artery.

• Transcranial Doppler test for blockages in the large brain arteries. This test is similar to the carotid ultrasound, although the sound waves go through the patient's skull instead of his neck.

• Cerebral angiogram to look for atherosclerosis or a brain aneurysm. The patient will be sedated to minimize his anxiety and discomfort during this procedure. A long, thin catheter, or tube, is inserted into a large artery in his groin, then maneuvered all the way through blood vessels into his chest. Once the tube reaches his carotid artery, dye is injected, which travels through the artery into the brain. Then a series of X-rays is taken to spot any abnormalities in the blood vessels of the brain. Because this procedure carries a slight risk of causing another stroke, it will be performed only if other tests are inconclusive.