Prevention of venous thromboembolism in the ICU.

BACKGROUND Although venous thromboembolism (VTE) is an important cause of morbidity and mortality in critical care unit patients, the risk of VTE and its prevention have been poorly characterized in this population. Evidence-based thromboprophylaxis guidelines are also not available for these critically ill patients. OBJECTIVES To review the prevalence of VTE, to summarize the available clinical trials of thromboprophylaxis, and to outline a practical approach to the prevention of VTE in critical care unit patients. METHODS Systematic review of the relevant literature. RESULTS Most patients in critical care units have at least one major risk factor for VTE, and many patients have multiple risk factors. Objectively confirmed deep-vein thrombosis (DVT) rates varied from 13 to 31% among the four prospective studies in which critical care unit patients did not receive prophylaxis. We were able to identify only three randomized trials of thromboprophylaxis conducted in critical care units. The results of these studies suggest that both low-dose heparin and low-molecular-weight heparin are efficacious in preventing DVT compared with no prophylaxis. Fourteen studies reported that compliance with some form of thromboprophylaxis occurred in 33 to 100% of critically ill patients. CONCLUSIONS There is a paucity of data assessing the risks and prevention of VTE in critical care settings. Selection of prophylaxis for these challenging patients involves a consideration of the thromboembolic and bleeding risks, both of which may vary in the same patient from day to day.