What criteria are appropriate for determining whether a surgical site infection is superficial or deep?

The determination of whether a surgical site infection (SSI) is superficial or deep largely revolves around the characteristics of the infection, specifically where the purulent drainage comes from. Superficial infections are typically confined to the skin and subcutaneous tissue, meaning they affect only the outer layers of the body. In contrast, deep infections penetrate through the subcutaneous tissue and may involve deeper structures, such as fascia, muscle, or other internal organs.

When purulent drainage is observed, its origin provides critical clues to the depth of the infection. If the drainage is from a wound that appears to be only on the skin surface, it suggests a superficial infection. Conversely, if the drainage is coming from a deeper area, possibly correlating to deeper layers of tissue involvement, it indicates a deep surgical site infection. Therefore, examining the source of purulent drainage is a key criterion for classification.

Other options, while relevant in their own contexts, do not specifically address the classification of the infection based on the infection’s characteristics. The location of the incision alone does not determine the infection's depth; it merely indicates where the procedure was performed. The timing of the surgery and the method employed also do not give speculations about the potential infection's depth, focusing instead more on