Classification of Wound by Sterility

The Centers for Disease Control and Prevention (CDC) “Guidelines for prevention of surgical site infection” identifies four surgical wound classifications.

CLASS I: CLEAN WOUNDS

* an uninfected surgical wound in which no inflammation is encountered and the respiratory, alimentary, genital, or uninfected urinary tracts are not entered.
* clean wounds are primarily closed and, if necessary, drained with closed drainage.
* Surgical wound incisions that are made after nonpenetrating (ie, blunt) trauma should be included in this category if they meet the criteria.

CLASS II: CLEAN-CONTAMINATED WOUNDS

* a surgical wound in which the respiratory, alimentary, genital, or urinary tracts are entered under controlled conditions and without unusual contamination.
* Specifically, surgical procedures involving the biliary tract, appendix, vagina, and oropharynx are included in this category, provided no evidence of infection is encountered and no major break in technique occurs.

CLASS III: CONTAMINATED WOUNDS

* open, fresh, accidental wounds.
* surgical procedures in which a major break in sterile technique occurs (eg, open cardiac massage) or there is gross spillage from the gastrointestinal tract and incisions in which acute, nonpurulent inflammation is encountered are included in this category.

CLASS IV: DIRTY OR INFECTED WOUNDS

* old traumatic wounds with retained or devitalized tissue and those that involve existing clinical infection or perforated viscera.
* This definition suggests that the organisms causing postoperative infection were present in the wound before the surgical procedure.