Wound management (Proceedings)
Dogs and cats are very commonly presented for management of acute or chronic wounds in veterinary practice. The goal of wound management is to accelerate the healing process and not to interfere with it. Therefore, the management of the wounds requires a good understanding of the healing process of wounds to be able to treat them effectively.
When an animal is presented for the management of an acute or chronic wound precautions should be taken not to further contaminate the wound. While a physical examination is performed to evaluate for any life threatening injury the wound should be covered with a light sterile bandage. This will help prevent contamination wit resistant bacteria present in the clinic. After the animal has been stabilized, the wound should be evaluated and cleaned. Sterile gloves are required to manipulate the wound. Pain medication should be delivered appropriately to the animal.
Preliminary evaluationThe wound needs to be covered with a water-soluble lubricant or a wet sterile sponge before starting clipping. A large clipping is performed with a # 40 blade. After completion of the clipping, the water-soluble gel is eliminated with sterile saline. If the wound is important, tap water can be used first to eliminate the gross contamination and sterile saline should be used for the last flush. Any obvious foreign material should be removed manually.
After the wound has been flushed, a deep sample should be taken for culture and sensitivity. While results of the culture are pending, the animal should be placed under broad-spectrum antibiotics. The most common bacteria in a wound are skin contaminant unless the trauma happened in a specific environment that may contaminate the wound with different bacteria. Usually a first generation cephalosporin is offering an adequate coverage.
The wound should then be evaluate for exposure of vital structure such as artery, vein, nerve, and joint. If the femoral artery or the sciatic nerve are exposed it is recommended to move tissue to cover these structures. Joints if exposed need to be aggressively flushed to remove the foreign material and closed over a drain.
The decision of closing a wound is made on the amount of contamination present in the wound, the time since injury happened, the amount of devitalized tissue. Four options are available to the surgeon; primary wound closure, delayed primary wound closure, secondary wound closure, and second intention healing. As a general rule, the wound is better left unsutured if a surgeon doubts the success of primary or delayed primary closure.
Primary wound closure
Primary wound closure entails closure of the wound relatively soon after it has been inflicted. Ideally, primary closure should be performed when the animal is otherwise in good condition. Additional requirements are a short time lap (< 6 hours) since injury and a minimal degree of contamination and tissue trauma. A thorough surgical debridement and lavage to provide tissue suitable for suturing are required for a successful outcome. Closure should be possible in the presence of good hemostasis without tension and dead space.
Surgical debridement consists of removing non-bleeding tissue. Surgical debridement is not performed immediately after the injury. During the first 24 hours after an injury, the blood vessels are vasoconstricted. If surgical debridement is performed while intense vasoconstriction is present, viable skin might be removed. This might be a serious issue later when the wound is closed. It is preferable to let the ischemia demarcate itself and then perform a surgical debridement. However, the debridement phase can be helped with bandage technique.
Most wounds created by a sharp object have low levels of bacteria and minimal soft tissue damage. They are amenable to primary closure. Crush wounds have more severe soft tissue trauma and contamination. They are usually closed with delay primary or secondary closure.
Primary closure should eliminate dead space and provide a good anatomical apposition of tissue. The amount of suture should be maintained to a minimum because it can act as a nidus for bacteria. Monofilament absorbable sutures of a small size are recommended.
Delayed primary closure
Delayed primary wound closure is wound closure 3 to 5 days after the time of infliction of the wound during which time the wound is medically managed to improve its chances of healing. Delayed primary closure is indicated for recent wounds with severe contusion, heavily contaminated wounds, or wound from a sharp object of several days duration. Mechanical debridement and lavage should be applied daily to the wound until closure is judged appropriate.