<unk>  is an emergency procedure to get vascular access, in which the vein is exposed surgically and then a cannula is inserted into the vein under direct vision. It is used in trauma and hypovolemic shock, when peripheral cannulation is difficult or impossible. The saphenous vein is commonly used, but antecubital and femoral vessels are also suitable. Complications of<unk>  include cellulitis, hematoma, phlebitis, perforation of the posterior wall of the vein, venous thrombosis and nerve and arterial transection.
1. Prepare the skin of the ankle with antiseptic solution and drape the area
2. Infiltrate the skin if time permits
3. Identify the surface anatomy of the greater saphenous vein: 2 cm anterior and superior of the medial malleolus. Perform a full-thickness transverse skin incision of 2,5 cm
4. Identify the vein with blunt dissection and dissect it free from the accompanying structures.
5. Elevate and dissect the vein for a distance of approximately 2-cm, to free it from its bed.
6. Ligate the distal, mobilized vein, leaving the suture in place for traction
7. Pass a tie about the vein more proximally
8. Make a small transverse incision (venotomy) and gently dilate the venotomy with the tip of a closed hemostat.
9. Introduce a cannula through the venotomy and secure it in place by tying the upper ligature about the vein and cannula. The cannula should be inserted an adequate distance to prevent dislodging.
10. Attach the intravenous line to the cannula.
Venous cutdown
Venous stasis
Adhesion 
Wound dehiscence
Ischemia
Crush injury
Clubbing
Venous translucence