The goal of our work was to test sensitivity of the duplex ultrasound examination in making a sapheno-femoral junction diagnosis in lying patients. For this reason we tried to find out whether in ultrasound examination of lumen diameter of the great saphenous vein (B-mode) the speed of blood flow and reflux detection (CFM, pulse Doppler detection) are influenced by the position of a patient when lying and when standing. We examined 70 lower limbs of 70 different patients (47 women and 23 men) in whom the sapheno-femoral junction was not diagnosed when examined in the lying position. The difference in the lumen diameter of the great saphenous vein measured when lying and when standing was statistically significant in our group of patients (p < 0.01). Decreased blood flow when standing was also statistically significant (p < 0.01). In any of the 50 examined lower limbs with the competent sapheno-femoral junction during the Valsalvov's manoeuvre when lying was not proved reflux nor it was proved when standing ( CFM, pulse Doppler detection). The examination of the venous reflux in the lying position is a physiologic, delicate, and at the same time reliable method. The lying position is comfortable for both the patient and the physician and as we proved, compared to ultrasonography in the vertical position, it does not lack needed sensitivity.

Keywords: Blood Flow Velocity; Female; Humans; Male; Posture; Saphenous Vein /diagnostic imaging/; Ultrasonography, Doppler, Duplex; Venous Insufficiency /diagnostic imaging/