Detection and prevention of deep venous thrombosis.

Deep venous thrombosis (DVT) is a significant problem in the postoperative course of high-risk patients. Risk factors that further predispose patients to DVT include obesity, age over 40 years, smoking, dehydration, and a prior history of thromboembolism. Diagnosis of DVT by physical examination and medical history is difficult; objective diagnostic techniques are often required. Considerable emphasis has been placed on the cost-effectiveness of implementing prophylactic measures in patients who are at high risk for developing DVT. Physical maneuvers attempt to reduce stasis and enhance venous return and pharmacologic approaches alter blood coagulability. The drug therapy used in preventing DVT consists of dextran, low-dose heparin, a combination of low-dose heparin and dihydroergotamine, and warfarin. Effective prophylactic regimens differ according to the type of patients at risk. Prophylactic therapy should be tailored according to the patient's disease and degree of risk.