Wounds are cuts, tears, burns, breaks, or other damage to living tissue. Wounds are often classified as clean, contaminated, or infected. Clean wounds are those created under sterile conditions, such as surgical incisions. The number of bacteria present determines the difference between contaminated and infected wounds.
Initial Wound Management
General wound care begins after the animal has been stabilized if it has undergone a trauma or is in shock. First aid, such as pressure to stop bleeding and basic bandaging, is generally done quickly.
Irrigation of the wound, called lavage, washes away both visible and microscopic debris. This reduces the risk of infection. A syringe is used to spray a solution onto or into the wound to clean it. Cleaning, or debridement, removes dead tissue and foreign material from the wound, reduces bacterial contamination, and helps prevent infection. If the wound is already infected, a sample may be collected for culture. Antibiotics are used to treat bacterial infections. Medications for pain relief are also usually given.
After initial inspection, irrigation, and cleaning, the veterinarian will decide whether to close the wound or to manage it as an open wound. Each wound must be assessed individually. If there is too little skin to close the wound, or the risk of infection is high, the wound may not be closed.
Wounds that are left open are usually managed with repeated bandaging and debridement. Wet-to-dry dressings are often used. These dressings help clean the wound at every bandage change. In the early stages of healing, the bandage may need to be changed as often as twice daily. Dry, nonstick dressings are used after healing has progressed. A wound may be closed after it has been treated for some time. This is common if an infection is present, but is successfully treated with antibiotics. Such wounds may be closed after 24 to 72 hours or longer.
Sutures, staples, or surgical glue can be used to close wounds. Sometimes, multiple layers of closure are required. For example, a deep layer of sutures may be needed to hold torn muscles together, along with an outer layer of sutures to close the skin over them.
Drains
Drains are used to help remove fluid from a wound or body cavity. This prevents the body from “walling off” the fluid, which can lead to infection. Drains can be passive or active. In passive drainage techniques, gravity draws the fluid out. In active drainage techniques, some type of suction is required to pull fluid from the wound. Laboratory tests may be run on the extracted fluid.
Bandages
Bandages help stop bleeding, keep the wound clean, protect the wound from further injury, and prevent the wound from excessive drying. Bandages have 3 layers.
The first layer of the bandage is directly on the wound and is sometimes called the dressing. It may be made of gauze or a mesh material that promotes early healing. This layer allows fluid to pass through to the secondary layer of the bandage, and also prevents tissue from drying out. Removing the bandages can cause some pain, but it helps debride and clean the tissue. Wet-to-dry bandages are made with moistened gauze that is placed directly on the wound. They can also be painful to remove but result in less tissue drying than dry bandages.
The second layer of a bandage absorbs fluid, pads the wound, and supports or immobilizes the limb. This layer is frequently cast padding or roll cotton.
The third layer provides some pressure on the wound, and holds the inner layers in place and protects them from the environment. This layer is usually adhesive tape or elastic wraps.
Before you bring your pet home, make sure you understand how to change your pet’s bandages and clean the wound, if necessary.
Surgery
Sometimes, a wound requires surgical treatment. Different types of wounds need different surgical procedures. For example, flaps of skin may be stretched over the wound to close it. Muscle flaps are also used for deep wounds. Sometimes, skin (or muscle) from other areas, or grafts, are taken and surgically attached to cover a wound.
Wound Healing
Wounds heal in 4 stages (see Box). Many factors affect how well and how quickly the wounds heal. Environment, the overall health of the animal, and drug treatments are among factors that influence healing. Temperature is one environmental factor that affects wound healing. The ideal temperature for wound healing is around 86°F (30°C). Cold weather may make wounds weaker, resulting in longer healing times. Wounds also need oxygen to heal. To maintain blood flow in the wound, bandages must not be excessively tight.
Stages of Wound Healing
Although there are many types of wounds, most undergo similar stages in healing. There are 3 major stages of wound healing after a full-thickness skin wound. The duration of each stage varies with wound type, management, and the individual's overall health. Inflammation is the first stage of wound healing. It can be divided into several phases. Initially, blood vessels constrict to control bleeding, and then, within minutes, blood vessels dilate resulting in localized swelling. White blood cells migrate into the wound where they attack bacteria and clean up damaged tissue and foreign material. This cellular level debridement is essential to wound healing. Proliferation is the second stage of wound healing. In a healthy wound, fibroblasts and capillaries (small blood vessels) migrate into the area and create a framework for other cells to grow on and rebuild missing and damaged tissues. In a surgically closed wound, skin, or epithelial, cells can cover the incision within 48 hours. In an open wound, the scaffold (granulation tissue) must fill the wound before epithelial cells can migrate in, so this type of healing takes longer. This process is hindered if the wound is too dry. Bandaging helps to maintain a healthy environment for healing open wounds. Remodeling is the final stage of wound healing. During this period, the newly laid collagen fibers reorganize along lines of tension. This process forms a scar, and allows wound strength to increase slowly over a long period (up to 2 years). Most scars remain 15% to 20% weaker than the original tissue. |
The overall health of the animal affects all aspects of care and healing. Some conditions, such as anemia, may interfere with wound healing by reducing oxygen levels. Malnutrition may also interfere with the healing process.
Many topical drugs are used to treat wounds. These may be intended to promote natural wound closure, prevent infection, or reduce pain. However, other topical drugs (used for other purposes) may slow wound healing. Your veterinarian will consider the risks and benefits when choosing the most appropriate treatment.
Management of Specific Wounds
Some specific types of wounds have special requirements or treatments.
Cuts and Tears (Lacerations)
Lacerations are cuts or tears in the skin. If they do not involve deep tissue or have other significant problems, they are called uncomplicated simple lacerations. Such cuts are usually managed by complete closure; however, this may not be possible if the wound is dirty or infected. Deep cuts can be treated similar to simple ones, depending on the extent of the injury. Damage to muscles, tendons, and other tissues must be treated before a wound can be closed.
Bite Wounds
Bite wounds are a major cause of injuries, especially in animals that spend a lot of time outdoors. Cat bites tend to be small puncture wounds that frequently become infected. Dog bites vary from simple puncture wounds to deep, wide gashes. Cultures are often taken of puncture wounds to determine the best antibiotic treatment. If tissue damage is extensive, as in the case of many dog bites, more involved treatment may be needed. Serious injuries may exist even if only small puncture marks or bruising are seen on the surface. For example, ribs may be broken or internal organs seriously damaged. For these reasons, any bite should be examined as soon as possible by a veterinarian. After examination, the wound is generally cleaned thoroughly. Antibiotics and pain medication are commonly administered.
Degloving Injuries
In degloving injuries, the skin is sheared or torn off. Degloving injuries can occur on the limbs or torso as well as the paws. Loss of skin is often extensive, and deeper tissues are often involved. Animals hit by cars or caught underneath the hood often have degloving injuries. Sometimes the skin is not completely removed. It remains attached to surrounding skin but not to the tissues beneath the skin. The skin is loose, usually bruised, and fragile. It may die later because it lacks blood supply. Any dead skin or other tissue must be removed. Tissue that can heal is usually saved. Infection is a major complication, and preventing infection is a main goal of treatment.
Gunshot Injuries
In gunshot injuries, most of the damage is not visible, as the wounds are typically deep. Gunshot wounds are also contaminated because the bullet or pellet drags skin, hair, and dirt through the wound. If the bullet exits the body, the exit wound will be larger than the entrance wound. High-speed bullets create shock waves that affect surrounding tissue and organs, causing blunt force trauma as a result.
Often, surgery is needed to determine the amount of damage done by a gunshot wound. Organ and deep tissue injuries can be life-threatening. Fractures are common and may require additional treatment or surgery.
Pressure Wounds
Pressure wounds, also called decubital ulcers, develop as a result of prolonged pressure on an area of skin. They are most common in paralyzed or immobile animals. When tissue does not get enough blood or oxygen, it begins to die. Pressure wounds can be extremely difficult to treat and are best prevented. Preventive measures include changing the position of the animal frequently, maintaining adequate nutrition and cleanliness, and providing a sufficiently padded bed. If pressure wounds are mild or caught early, cleaning and bandaging may be enough to prevent further damage. More severe wounds require surgery. Grafts may be needed.
For More Information
Also see professional content related to wound management for animals.
