Wound classification
Clean (~2% infection), clean-contaminated (~10%), contaminated (up to 20%), dirty (over 40%). This drives antibiotic prophylaxis decisions.
Antibiotic prophylaxis as a single IV dose within 60 minutes before incision, with an additional dose if the operation exceeds the antibiotic half-life or with major blood loss.
Preoperative measures (NICE NG125)
Shower with soap on the day of surgery. Hair not routinely removed; if necessary use electric clippers, not razors. Mechanical bowel preparation not routinely recommended. Nasal decolonisation for S. aureus carriers in high-risk procedures such as cardiac surgery.
Intraoperative measures
Alcoholic chlorhexidine skin prep (NICE first-line). Maintain normothermia above 36 degrees. Optimise tissue oxygenation. Triclosan-coated sutures for contaminated wounds. Closed suction drains removed early.
Common organisms by procedure
Skin/soft tissue — S. aureus. Colorectal — E. coli, B. fragilis, Enterococcus. Biliary — gram-negative enterics. Orthopaedic implants — S. aureus including MRSA. The antibiotic prophylaxis question follows from the organism question.
Management of established SSI
Source control: open the wound, drain collections, send pus for culture, treat empirically then narrow. Structure your OSCE answer in NICE order: preoperative, intraoperative, postoperative. Mention NG125 by name once. The visual framework is in SurgAtlas at surgatlas.com.