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Wound Healing
Updated: 06/02/2003
Wound: from the Old English word, wund
Wound healing consists of an orderly progression of events that reestablish the integrity of the damaged tissue. The initial wound touches off a series of programmed, separate yet interdependent responses to the injury, including inflammation, epithelialization (growth of new skin), angiogenesis (blood vessel regeneration), and the accumulation of matrix, the cells necessary to heal the tissue. Many wounds pose no challenge to the body's innate ability to heal; some wounds, however, may not heal easily either because of the severity of the wounds themselves or because of the poor state of health of the individual. The Life Extension Foundation has designed this protocol to support and enhance the healing of internal and external wounds that fall into this category. (For related information on how to support the body's ability to heal and rebuild itself, refer to the Catabolic Wasting and Muscle Building protocols.) Any wound that does not heal should be examined by a healthcare professional because it might be infected, might reflect an underlying disease such as diabetes, or might be a serious wound requiring medical treatment. Always inform your healthcare provider of all supplements and treatments you are using.
Types of WounDS
Although all wounds follow roughly the same healing process, there are many different causes of wounds. Partial-thickness wounds penetrate the outer layers of the skin (the epidermis and the superficial dermis) and heal by regeneration of epithelial tissue (skin). Full-thickness wounds involve a loss of dermis (deeper layers of skin and fat) and of deep tissue, as well as disruption of the blood vessels; they heal by producing a scar. Wounds are classified by stage. Stage I wounds are characterized by redness or discoloration, warmth, and swelling or hardness. Stage II wounds partially penetrate the skin. Stage III describes full-thickness wounds that do not penetrate the tough white membrane (fascia) separating the skin and fat from the deeper tissues. Stage IV wounds involve damage to muscle or bone and undermining of adjacent tissue. They may also involve the sinus tracts (red streaks indicating infected lymph vessels).
One medical term for a wound is an ulcer. An ulcer is an open sore on the skin (or a mucous membrane) that causes destruction of surface tissue. An ulcer can be shallow or deep and crater-shaped. Ulcers are usually inflamed and painful.
Traumatic Ulcers
An injury caused by any kind of accident (or trauma) can result in a wound that affects the skin, blood vessels, bones, muscles, soft tissue, or organs that may result in development of an ulcer.
Arterial Ulcers
The arteries supply blood, which carries vital oxygen required by cells to live. If arterial circulation is partially or completely blocked, the tissue will begin to die, resulting in a painful wound. Impaired circulation of this type usually occurs in the extremities (arms and legs), especially on the top of the foot. Impaired circulation is signaled by lack of pulse; cool or cold skin; skin that appears shiny, thin, and dry; loss of skin hair; and delayed capillary return time. (To test capillary return time, briefly push on a skin area and then release: normal color should return in 3 seconds or less.) Treatment of arterial ulcers has two goals: re-establishing circulation with medical treatment and healing the wound(s).
Venous Ulcers
Veins carry deoxygenated blood back to the lungs. Veins contain valves that prevent backflow, but when these valves become incompetent, too much blood remains in the tissues. This condition is called congestion. Venous congestion commonly affects the legs, causing swelling (edema) and a brownish discoloration from the hemoglobin of the immobile red blood cells that leak out. Venous ulcers are the most common wounds affecting the legs and are frequently found on the ankles. Venous ulcers are shallow and not too painful. They may have a weeping discharge. Although venous valves cannot be repaired, the return of blood through the veins can be improved by physical activity and by compression which can be supplied by compression stockings, dressings, or mechanical pumping devices.
Diabetic Foot Ulcers
Diabetes results in a narrowing of the small arteries which can cause ulcers. This narrowing cannot be resolved, but it can be prevented by careful glucose control. Diabetes also causes peripheral neuropathy and the loss of sensation, especially sharp/dull discrimination, in the legs and feet. For this reason, injuries to the feet may go unnoticed and can progress into serious wounds. In addition, peripheral neuropathy can cause deformity of the foot (Charcot foot deformity) because of inappropriate stresses being placed on the bones, resulting in microfractures; this deformity in turn results in bony prominences and swelling that contribute to ulceration. Neuropathy also cannot be cured, but careful glucose control slows its progress. Diabetics must be extremely vigilant about foot care and should seek immediate medical attention for any wounds. Special shoes can help relieve pressure on the feet.
Pressure Ulcers
Also known as bedsores, pressure ulcers are very common in older and immobile persons. When too much pressure is placed on them, cells do not get enough oxygen. Pressure of this type occurs when cells are sandwiched between a bony prominence (elbow, hip, heel, or tailbone) and a hard surface (bed or wheelchair). Those cells closest to the bone begin to die, and the wound spreads toward the skin surface. Thus, a pressure ulcer indicates not only a surface wound, but also a deep tissue wound. The risk of pressure ulcers can be reduced by enhancing mobility, maintaining skin and general health, ensuring good nutrition, and monitoring weight (patients should be neither too heavy nor too light).
Burns
Most burns occur in the home, particularly from accidents. Burns can be caused by scalding hot liquids, grease fires, car accidents, chemical explosions, frayed electrical cords, house fires, hot objects (stoves, irons, grills, tailpipes), or even the sun. A first-degree burn results in a superficial reddened area on the top layer of the skin (epidermis) like that caused by a mild sunburn. A second-degree burn involves the epidermis and second layer of the skin. It results in a blistered injury that heals spontaneously after the blister fluid has been removed. A third-degree burn penetrates all layers of the skin and will usually require surgical intervention in order to heal. Superficial burns usually heal on their own within 2 weeks with routine wound care and protection from infection. Deeper burns (second and third degree) require medical attention, including nutritional support and assessment of lung function, and may require skin grafts and vascular or reconstructive surgery. Immediate care of a burn consists of cooling the affected area with ice or ice water.
Stages of Wound HealiNG
Wounds with even edges that come together spontaneously (minor cuts) or can be brought together with sutures usually heal well with routine wound care. Wounds with rough edges and tissue deficit (a crater) may take longer to heal. When there is a crater and the edges of a wound are not brought together (left open intentionally), bumpy granulation tissue grows from the exposed tissue. The granulation tissue is eventually covered by skin that grows over the wound from the cut edges to the center. When healing is complete, the granulation tissue develops into tough scar tissue. All wounds heal in three stages.
Inflammatory Stage
This stage occurs during the first few days. The wounded area attempts to restore its normal state (homeostasis) by constricting blood vessels to control bleeding. Platelets and thromboplastin make a clot. Inflammation (redness, heat, swelling) also occurs and is a visible indicator of the immune response. White blood cells clean the wound of debris and bacteria.
Proliferative Stage
After the inflammatory stage, the proliferative stage lasts about 3 weeks (or longer, depending on the severity of the wound). Granulation occurs, which means that special cells called fibroblasts make collagen to fill in the wound. New blood vessels form. The wound gradually contracts and is covered by a layer of skin.
Maturation and Remodeling Stage
This stage may last up to 2 years. New collagen forms, changing the shape of the wound and increasing strength of tissue in the area. Scar tissue, however, is only about 80% as strong as the original tissue. The body's ability to heal during this stage is diminished in the elderly.
Wound CaRE
There are four basic steps to follow in caring for any wound. Perhaps the most important factor in wound healing is compliance: in other words, caring for the wound consistently and correctly.
Debride and Cleanse
Debridement means the removal of dead tissue. Debridement can be accomplished in an autolytic manner, meaning the wound itself is encouraged to do this task by the use of dressings. A medical professional may also use biochemical enzymes; wet-to-dry dressings (in which a wet dressing is allowed to dry, trapping material in it, and is then carefully removed); or mechanical implements such as scalpel or scissors to remove dead tissue from more serious wounds. Cleansing refers to the removal of any foreign debris from the wound (such as residuum from previous dressings) and any bacteria. Cleansing is usually accomplished by irrigating the wound with fluid from a disposable syringe.
Many previously accepted wound-cleansing solutions have been found to be toxic to fibroblasts and lymphocytes, the cells required to heal wounds. These solutions include povidone-iodine, acetic acid, iodophor, hydrogen peroxide, and Dakin's solution (sodium hypochlorite). Commercially prepared solutions are not regulated by the FDA, and many have been found to be cytotoxic. The only acceptable wound-cleansing solution is normal saline solution (0.9% sodium chloride, or salt, in water). Normal saline solution effectively removes contaminants and has the same salt concentration as the fluid in cells, so it does not damage cells by pulling water out of them. Normal saline is also inexpensive and readily available.
Maintain a Moist Environment
During wound healing, cells and fluid are slowly exuded (or discharged). The exudate provides an environment that stimulates healing because it contains white blood cells, growth factors, and other special enzymes and hormones. A moist environment preserves this exudate, speeding wound healing and promoting skin growth. It also prevents dressings from adhering to the wound and damaging the fragile tissue when the dressing is removed. A moist environment can easily be maintained using gauze moistened with normal saline solution (or with a Vaseline-based prescribed ointment obtained from a physician).
Normal saline solution will support autolytic debridement, absorb discharge, and trap bacteria. For partial-thickness wounds with no infection, polyvinyl dressings, which are semipermeable to oxygen and impermeable to bacteria, can also be used. Polyvinyl dressings have the advantage of concentrating the cells responsible for healing in the wound bed, but the disadvantage is that they are adhesive and may therefore damage the fragile skin surrounding the wound. Hydrocolloid dressings are not adhesive and are impermeable to oxygen and bacteria, but may leave a residue in the wound, which must then be removed. Absorptive dressings are used on wounds with a lot of discharge.
It is critical that the first two steps of wound care be performed regularly and gently. Dislodging the fragile granulation tissue or skin that is forming in the wound bed will delay healing. For most wounds, the first two steps can be accomplished easily and effectively by using gauze that is kept moist with normal saline solution.
Prevent Further Injury
In order to prevent further injury, the initial cause of the wound must be determined and addressed as described above and the area must be protected from additional trauma.
Provide Materials for Healing
Proteins, made up of amino acids, are necessary for all phases of wound healing, including angiogenesis, fibroblast proliferation, collagen synthesis, and scar remodeling. Proteins also support the immune system, helping to prevent infection. One study found that protein depletion before surgery is a risk factor in wound infection (McPhee et al. 1998). Fats and carbohydrates are also needed to supply the extra energy used in healing and to prevent proteins from being used for energy. Water is necessary to replace losses through vomiting, bleeding, wound discharge, and fever. Vitamins and minerals also play key roles in the healing process, as will be discussed later.
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