Phases of Wound Healing -Hemostasis stage, Inflammatory process, Proliferative Phase
The stages of wound healing proceed in an organized way and follow four Stages:
- Hemostasis
- Inflammation
- Proliferation
- Maturation
Although the Phases of Wound Healing are linear, wounds can progress backward or forward depending on internal and external patient wound conditions. The four stages of wound healing are:
What is Hemostasis Phases of Wound Healing ?
Hemostasis Phases of Wound Healing is the process of wound being closed by clotting. Hemostasis starts when blood leaks out of the body or wound. The first step of hemostasis is when blood vessels constrict to restrict the blood flow. Next, platelets stick together in order to seal the break in the wall of the blood vessel. Now Finally, coagulation occurs and reinforces the platelet plug with threads of fibrin which are like a molecular binding agent. The hemostasis stage of wound healing happens very fast. The platelets adhere to the sub- endothelium surface within some seconds of the rupture of a blood vessel’s epithelial wall. After that, the first fibrin strands begin to adhere in about sixty seconds. As the fibrin mesh begins, the blood is transformed from liquid to gel through pro-coagulants and the release of prothrombin. The formation of a clot keeps the platelets and blood cells trapped in the wound area. The thrombus is important in the stages of wound healing but becomes a problem if it detaches from the vessel wall and goes through the circulatory system, possibly causing a stroke and heart attack.
What is Inflammatory Phases of Wound Healing ?
Inflammation is the second stage of wound healing and it begins right after the injury when the injured blood vessels leak transudate (made of water, salt,protein) causing localized swelling. Inflammation controls both bleeding and prevents infection. The fluid engorgement allows healing and repair cells to move to the area of the wound. During the inflammatory phase of Wound Healing, damaged cells, pathogens, and bacteria are removed from the wound site. These white blood cells, growth factors, nutrients and enzymes create the swelling, heat, pain and redness commonly seen during this phase of wound healing. Inflammation is a natural part of the wound healing process and only problematic if excessive or prolonged.
What is Proliferative Phase in Wound Healing ?
The proliferative phase of wound healing is when the wound and wound area is rebuilt with new tissue made up of collagen and extracellular matrix. In the proliferative phase of wound healing process, the wound contracts as new tissues are built. Also, a new network of blood vessels must be constructed so that the granulation tissue can be healthy and receive sufficient oxygen and nutrients. Myofibroblasts cause the wound to contract by gripping the wound edges and pulling them together using a mechanism similar to that of smooth muscle cells. In healthy stages of wound healing, granulation tissue is pink or red and uneven in texture. Healthy granulation tissue does not bleed easily. Dark granulation tissue can be a sign of infection and poor perfusion. In the final phase of the proliferative stage of wound healing, epithelial cells resurface the injury area. It is important to remember that epithelialization happens faster when wounds and wound area are kept moist and hydrated. When occlusive or semiocclusive dressings are applied On wounds within 48 hours after injury, they will maintain correct tissue humidity to optimize epithelialization.
What is Maturation Phase in Wound Healing ?
Maturation Phase in Wound Healing is also called the remodeling stage of wound healing, the maturation phase of wound healing is when collagen is remodeled from type III to type I and the wound area fully closes. The cells that had been used to repair the wound but which are no longer needed are removed by apoptosis, or programmed cell death. When collagen is laid down during this phase of wound healing, it is disorganized and the wound is thick. During the maturation phase of wound healing, collagen is aligned along tension lines and water is reabsorbed so that the collagen fibers can lie closer together and cross-link. Cross-linking of collagen reduces scar thickness and also makes the skin of the wound area stronger. Generally, remodeling of wound begins about 21 days after an injury and can also continue for a year or more time. Even with cross-linking, healed areas of wound continue to be weaker than uninjured skin.
The stages or phases of wound healing are a complex and fragile process. Failure to progress in the stages of wound healing can lead to chronic wounds. Factors that leads chronic wounds are venous disease, infection, diabetes and metabolic deficiencies of the patients. Careful wound care and Wound Healing can speed up the stages of wound healing by keeping wound and wound areas moist, clean and protected from infection and reinjury .
