[Prevention of thromboembolism and therapy. Introduction]

One-third of all surgical patients develop a deep phlebothrombosis. This frequency of thrombosis after injuries of the lower extremities is estimated at 65%. Most of the thromboses do not become clinically manifest. Ninety-two percent of all fatal pulmonary embolisms originate from a clinically inapparent thrombosis. The ideal prophylaxis should compensate for the undesired effects of an operation or injury on the coagulation system, without subjecting the patient to the danger of elevated tendency to bleed. The discussion of this subject should help to clarify the present successes and risks of thromboembolism prophylaxis and therapy.