Hemostasis

Control of bleeding is necessary for both hemodynamic stability and for proper evaluation of a wound. Bleeding most often occurs from the subdermal plexus and superficial veins. Direct pressure with saline-soaked sponges or gauze is usually effective in stopping this type of bleeding.

Bleeding from an exposed lacerated vessel is best controlled by direct pressure with a gloved fingertip directly onto the vessel. Once bleeding is halted, persistent control can be achieved by clamping the involved vessel, isolating a short length, and ligating with absorbable synthetic suture (typically 5-0). This approach is most useful for rapidly bleeding minor vessels in the extremities, but major arteries of an extremity should not be ligated. Extreme caution must be exercised in the face because of the proximity of important facial structures. Scalp lacerations can bleed extensively from the wound edges due to the highly vascular subcutaneous layer. This bleeding can be controlled by the use of specially designed clips applied along the wound edges. For bleeding wounds where the involved vessel is not visible, a figure-of eight or horizontal mattress suture applied adjacent to the wound edge near the site of bleeding will sometimes achieve control. However, this technique may obstruct significant blood flow and leave nonviable tissue in the wound.

Chemical means of hemostasis include epinephrine, Gelfoam, Oxycel, Actifoam, and cyanoacrylates. Topical epinephrine is not very effective. More commonly, epinephrine is mixed with local anesthetics in concentrations of 1:100,000 or 1:200,000 and injected into the wound area. This will induce local vasoconstriction that will allow a longer duration of anesthesia and a larger total dose due to the depot effect of the vasoconstriction. Epinephrine should never be used in end organs such as fingers, toes, and tip of nose, ears, and penis. Although there is a theoretical risk of increased infection with the addition of epinephrine to local anesthetics, observational studies on emergency department wound repair have not found a significant increase in the incidence of wound infection after suturing. Gelfoam, made from denatured gelatin, has no intrinsic homeostatic properties and works by the pressure it exerts as it becomes a fluid-filled sponge. Oxycel, a cellulose derivative, and Actifoam, a collagen sponge, react with blood, forming an artificial clot. These products are not particularly effective for actively bleeding wounds, as the blood can wash them out. Cyanoacrylates form a gluelike substance, bringing wound edges together when applied to the skin surface. Cyanoacrylates should never be applied into the depth of a wound.

Bipolar electrocautery can achieve hemostasis from blood vessels smaller than 2 mm in diameter but, if improperly or too extensively applied, results in tissue necrosis. Electrocautery units are not routinely available in many emergency departments. Battery-powered hand-held cautery units are more readily available but do not generate sufficient heat to produce coagulation in vessels larger than capillaries.

Extremity wounds that are refractory to direct pressure, ligation, or cautery may require a tourniquet. Although helpful in stopping exsanguination, tourniquets may compress and damage underlying blood vessels and nerves, reducing tissue viability. The simplest tourniquet to use in an emergency department is a blood pressure cuff placed proximal to the wound and inflated above the patient's systolic pressure. Elevating the extremity to reduce venous blood volume prior to cuff inflation is useful. If an extremity tourniquet is needed to control bleeding, the patient is best explored and repaired in the operating room and a surgeon should be immediately consulted.

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