Vascular ultrasound in the intensive care unit.

Ultrasonography plays an increasingly important role in the evaluation of the vascular system. It is especially useful for the intensive care patient because of its ability to be performed at the patient's bedside, as well as the relatively high frequency of vascular complications in the ICU. Ultrasonography is the method of choice for evaluation of deep vein thromboembolic disease of the lower extremity in all patients, demonstrating excellent sensitivity and specificity for this condition. It also should be the initial method of evaluating upper extremity deep vein thrombosis. It may be limited in this assessment, however, because it does not reliably demonstrate the central subclavian and innominate veins, and therefore may be inadequate for evaluation of malfunctioning central venous catheters. Ultrasonography can reliably identify the presence of abdominal aortic aneurysms, although computed tomography is better able to demonstrate location and extent of these lesions. Finally, ultrasonography can be used to diagnose complications of arterial catheterization and, in selected patients, may direct compression of pseudoaneurysms, resulting in thrombosis and thereby averting surgical repair.