[Dextran and hemodilution in the prevention of postoperative venous thrombo-embolism (author's transl)].

A retrospective study was made to evaluate the effects of two preventive measures on deep venous thrombosis. The first group consists of 147 patients operated upon for biliary tract disease and 118 operative at the hip. The prophylactic measures consisted of dextran and ASA. The second group comprises 52 patients who underwent biliary tract surgery and 40 a hip intervention. During the operation they were submitted to a moderate normovolemic hemodilution (Hemat. 27%) only. During the postoperative period this group received no other prophylactic measures or therapy except for routine physical therapy. This study suggests that moderate normovolemic hemodilution is the best prophylaxis for deep venous thrombosis. Indeed, in the first group 10% of those operated upon for biliary tract disease developed a deep venous thrombosis as detected by the fibrinogen-I 25 test and phlebography (0,68% massive lethal pulmonary embolism). The incidence was 37,2% after hip surgery (1,6% massive lethal pulmonary embolism). Of those operated with moderate normovolemic hemodilution no deep venous thrombosis was detected in the biliary surgery group and only 10% in the hip surgery group. None of them died of a pulmonary embolus. The mechanisms by which normovolemic moderate hemodilution prevents the development of deep venous thrombosis are discussed.