Why is a surgical wound especially vulnerable to contamination during its first 24 hours?

A surgical wound is considered most susceptible to surface contamination during the first 24 hours following a procedure. This vulnerability exists because the wound is in the initial inflammatory phase of healing, during which the body is just beginning to form a protective seal.1

During this first day, platelets adhere to collagen exposed by the surgical incision to form a plug, and fibrin joins these platelets to create a clot. While this process initiates the repair, the wound surface has not yet developed the robust, continuous barrier provided by fully formed granulation tissue or complete epithelialization. Because the wound is still fresh and the protective scab or clot is in its early stages of development, it lacks the full physical barrier necessary to effectively block the entry of foreign material and bacteria. Consequently, medical professionals apply occlusive dressings during this period to protect the site from external contamination and facilitate the healing process.12