The thrombo-embolic risk in surgery.

Postoperative deep-vein thrombosis can lead to fatal pulmonary embolism on one side, and the development of a disabling postthrombotic syndrome, which can occur after some time. General thrombo-embolic prophylaxis can reduce the risk of postoperative thrombo-embolic complications. Predisposing factors include age, obesity, immobilization and recumbency. Cardiovascular diseases, malignant neoplasms, venous disorders, diseases associated with increased viscosity of blood, past deep-vein thrombosis and pulmonary embolisms, some infectious diseases with raised fibrinogen levels, and inherited or acquired clotting factor deficiency syndromes (antithrombin III, protein C, protein S) have an elevated risk of thrombosis. The surgery itself, when taking more than 20 minutes and performed under general anesthesia, is a major risk factor, as proven initiation of thrombosis is often on the operation table. Patients receiving regional or local anesthesia have a clearly reduced risk of thrombosis. After general surgery without thrombosis prophylaxis, a deep-vein thrombosis can be demonstrated by the fibrinogen uptake test in about 30% of all patients over the age of 40. After abdominal surgery an incidence of thrombosis of 14-33%, and after hip surgery an incidence of nearly 50%, have been established by means of the fibrinogen uptake test. However only 10% of these thromboses are expressed clinically. We therefore recommend Liquid Crystal Contact Thermography, which has a sensitivity of 94% and a specificity of over 80%, as a non-invasive, easily performed screening method in the diagnosis of deep-vein thrombosis. Apart from the physical methods, the use of heparin is also indicated in thrombo-embolic prophylaxis.(ABSTRACT TRUNCATED AT 250 WORDS)