Small and often silent pulmonary tromboembolism (synonyms: latent embolism, "silent killer") is a variant of venous pulmonary tromboembolism (PTE), which is not rare at all. It often represents a serious risk for surgical patients in particular. The Hrst attack of silent PTE does not seem very dangerous for the patient, but there is a possibility that part of the originál instable thrombus may become separated, which could lead to another attack of PTE with a possible serious or even fatal outcome. Recurrent separation of little throm- bi from the "maternal" thrombus represents another risky situation. This successive form of PTE may result in secondary pulmonary hypertensive disease. In our páper we attempt to point out some problems concerning diagnosis, therapy and prevention of small forms of PTE in all branches of surgery, especially in orthopedics, abdominal surgery, traumatology, plas tic surgery, gynecology and obstetrics.

        Key words: thrombophilia, thrombosis, pulmonary tromboembolism, silent embolism, "silent killer".