Phase 1: Hemostasis – Stop the bleeding!
Most of the bleeding that takes place during a surgery or other procedure is effectively controlled by holding pressure and letting the body’s natural system of coagulation take place, or by using tools like cautery or sutures to effectively clamp down small vessels. Hemostasis depends on the constriction of blood vessels and on properly functioning coagulation factors and platelets.
Most of the time we don’t have to think about this process, but there are several things that can derail it. Some common factors that increase bleeding risk include taking medications or supplements (ibuprofen, aspirin, and vitamin E to name a few), alcohol use, and increased blood pressure (chronic or even stress or pain induced). Excessive bleeding during a surgery or procedure can cause it to take longer and make it more difficult to complete. Bleeding afterwards can lead to increased bruising and the formation of a hematoma (a larger collection of blood under the skin).
Phase 2: Inflammation- Recruit the clean-up crew.
Inflammation is easily recognized as the redness, swelling, and pain experienced following an injury. This phase occurs in the several days following a procedure. Despite the discomfort, this is the body initiating the important process of bringing several types of immune cells to the site of injury (called chemotaxis). These cells are responsible for preventing infection and for cleaning up dead cells and debris from the wound. This step also prepares the wound for the next phases of repair and rebuilding. During this process, some harmful byproducts are formed and if inflammation persists beyond the expected time or does not efficiently move into the next phases of healing, incomplete or delayed wound healing may occur.
Anything that impairs blood flow to the wound or impairs the immune system can affect the inflammatory response. This includes smoking, diabetes, stress, poor sleep, older age, nutritional deficiency, and immunodeficiency. During this phase it is important to follow post-operative instructions carefully- including exercise recommendations and any special positioning, and to promptly seek care if signs of infection or excessive inflammation develop.
Phase 3: Proliferation- Repair the wound site.
Proliferation includes laying down new structural proteins and forming new blood vessels to repair the injury site. This process occurs in the days and weeks following injury, and one goal is “re-epithelialization,” or closing of the top layers of skin from the edges of the wound inward. At the end of this phase, the wound is closed but may still appear red and swollen.
Adequate oxygen at the wound site is critical here. Two common reasons for oxygen levels to be lower than normal include diabetes and smoking. This is in part because these two conditions lead to lack of blood flow and a decreased ability to form new blood vessels during the repair process (Guo et al 2010). Quitting smoking at least 4 weeks before surgery and continuing not to smoke during the healing process (and of course, beyond) is key. Poor sleep has also been shown to disrupt all phases of healing because the sleep-wake cycle is responsible for controlling several hormones and proteins involved in immune function and rebuilding tissue structures after injury. Studies have shown that people who suffer from sleep restriction take longer to close wounds and completely heal (Gethin et al 2022).
Phase 4: Remodeling- Shore up the wound site and return function to the tissue.
The final stage of wound healing starts about 3 weeks after the injury and may take years to complete. The goal of this phase is to clean up any unnecessary blood vessels and cells that are no longer needed to repair the wound, and to return the site to a near-normal state. During this process, more fragile type III collagen is replaced with stronger, type I collagen and crosslinking of collagen occurs. The wound becomes stronger, smaller, less swollen, and fades in color.
Optimal nutrition is important in all stages of wound healing, including remodeling. Adequate levels of protein, vitamins and minerals are essential to healing well. In subsequent newsletters we will discuss ways to optimize nutrition and exercise after a surgical procedure.
The bottom line: Healing is complex! Understanding the process and timeline of wound repair can help us improve recovery and manage our expectations. Look for more information on this topic in future “Buzzes.”