Fig. 1

Schematic diagram of deep veins in the lower limbs showing the compression points. The intensivist-performed compression ultrasound scan protocol consisted of compression of common femoral, femoral, and popliteal veins. Common femoral vein compression was performed at groin crease, saphenofemoral junction (SFJ) and confluence of femoral and deep femoral veins. Femoral vein compression was performed at 2 cm intervals along the vein below the confluence and popliteal vein compression was performed at the groin crease and the confluence of calf veins