Table I.

Types of surgical wounds and the risk of infection

Types of surgical wounds and the risk of infection		Risk of infection (%)
Clean	Elective procedure, primarily closed wound without trauma and with no evidence of infection or inflammation in the surgical site. Without compromising the integrity of the gastrointestinal tract, urogenital tract, respiratory tract, oral cavity and pharynx – providing aseptic technique has been used	< 2
Clean-contaminated	Procedures in which the urinary, respiratory or gastrointestinal tracts are entered under controlled conditions, without evident contamination with their contents. Procedures involving the biliary tract with no evidence of infection; procedures involving access through the oropharyngeal mucosa; clean emergency procedures; repeat surgery within 7 days of a clean procedure. Blunt trauma	< 10
Contaminated	Open post-traumatic wound, procedure with a violation of the aseptic technique; inflammation other than surgical site infection; penetrating trauma within less than 4 h of the procedure; chronic wound eligible for treatment with a skin graft	20
Dirty	Penetrating trauma within more than 4 h of the procedure; procedures involving devitalised tissues; evidence of infection at the surgical site. Preoperative perforation of the gastrointestinal, biliary or respiratory tracts	40