In all vascular procedures, including vascular trauma, proximal and distal control is mandatory before attempting repair or doing an arteriotomy. It is desirable to have a completely empty vascular segment in order to perform a vascular operation without unnecessary technical difficulties. To
achieve this, all branches for inflow as well as outflow from the segment must be controlled. Before clamping, systemic anticoagulation is usually necessary unless contraindicated by bleeding risk. The standard dose is 100 units/kg body weight of heparin given intravenously, but in practice, 5,000 units is usually adequate for an adult patient. It is important to be aware that the activity of heparin is halved within 1-2 h, so a repeated dose of 2,500 units might be required, especially if the surgeon notices increased clotting activity in the operating field. For local heparinization, flushing with a solution of 5,000 units of heparin in 500 ml Ringer's acetate or Ringer's glucose (10 units/ml) is recommended.
Control of the flow in the exposed vascular segments is achieved with different types of vascular clamps or with vessel-loops of cotton fabric or rubber. Doubly applied 2-0 or 3-0 ligatures can also be used for smaller branches. Intraluminal control with balloon catheters can also be effective (Fig. 15.2).
A vascular clamp should be chosen with an angle and shape that minimally disturbs the surgical exposure during the rest of the procedure. To avoid disrupting the often dorsally located plaques in arteriosclerotic arteries, clamps should preferably be applied horizontally and closed just enough to stop the blood flow (Fig. 15.3).
Temporary vascular clamps can be manufactured using vessel-loops or umbilical tape and a piece of rubber tubing (Fig. 15.4).
When there is active traumatic bleeding, a blindly applied vascular clamp can be dangerous and should be avoided. For full control, the injured vascular segment must be exposed. The bleeding vessel can be controlled by finger compression, a "peanut," or a "strawberry" until the vessel has been mobilized and the bleeding controlled. If this technique is not possible, external compression and packing of the wound with dressings under compression can be used while dissection is performed and adequate exposure obtained, but this usually results in significant blood loss.
In larger arteries such as the aorta, a Foley catheter of appropriate size can be used for the same purpose. Special catheters from different manufacturers are also available for occluding arteries. When balloons are used for proximal control they are easily dislocated and even blown out by the arterial pressure. This can be avoided by having an assistant manually support the catheter or by applying a vascular tape around the artery just proximal to the arteriotomy, thus preventing the balloon from being further dislocated distally.
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