Reference — Perioperative Nursing
Surgical Wound Classification
The CDC/National Research Council surgical wound classification system categorizes operative wounds by degree of contamination and predicted infection risk. Classification guides prophylactic antibiotic decisions, wound closure technique, and postoperative monitoring intensity.
Educational use only. Wound classification is determined by the surgeon intraoperatively and documented in the operative report. Infection risk percentages represent population-level estimates and vary by patient risk factors, surgical complexity, and hospital infection rates. This material supports nursing education and exam review. It is not medical advice and is not a substitute for clinical judgment, institutional policy, or medical direction. Always follow facility protocols and current provider orders.
Clean
CDC Definition
An uninfected operative wound in which no inflammation is encountered and the respiratory, alimentary, genital, or uninfected urinary tract is not entered. Wounds are closed primarily and, if necessary, drained with closed drainage.
Surgical Examples
- ✦Hernia repair
- ✦Thyroidectomy
- ✦Craniotomy (elective)
- ✦Total hip or knee arthroplasty
- ✦Breast biopsy
- ✦Cardiac surgery (sternotomy)
Nursing Implications
- ✦Standard surgical aseptic technique
- ✦Antibiotic prophylaxis may be used for implanted prostheses
- ✦Wound healing expected to be straightforward
- ✦Monitor for any signs of SSI — unexpected in this class
- ✦Patient education: keep incision dry for 24–48 hours, monitor for erythema or drainage
Clean-Contaminated
CDC Definition
An operative wound in which the respiratory, alimentary, genital, or urinary tract is entered under controlled conditions and without unusual contamination. Operations involving the biliary tract, appendix, vagina, and oropharynx are included in this category provided there is no evidence of infection or major break in technique.
Surgical Examples
- ✦Appendectomy (non-perforated)
- ✦Cholecystectomy
- ✦Hysterectomy
- ✦Bowel resection (elective, bowel prep completed)
- ✦Tonsillectomy
- ✦Nephrectomy
Nursing Implications
- ✦Antibiotic prophylaxis standard — administer within 60 minutes before incision
- ✦Monitor for SSI more vigilantly than Class I
- ✦Bowel prep completion and timing important to document
- ✦Closed-suction drainage if used — document output and character
- ✦Patient education: fever >101°F, purulent drainage, or wound opening = notify provider
Contaminated
CDC Definition
Open, fresh, accidental wounds; operations with major breaks in sterile technique (e.g., open cardiac massage) or gross spillage from the gastrointestinal tract; incisions in which acute, nonpurulent inflammation is encountered.
Surgical Examples
- ✦Perforated appendix (without abscess)
- ✦Traumatic wound (laceration — recent, within hours)
- ✦Bowel surgery with gross GI spillage
- ✦Operations with major break in sterile technique
- ✦Open fracture within 4 hours of injury
Nursing Implications
- ✦Higher SSI vigilance — monitor closely for first 7–10 days
- ✦Wound may be left open (delayed primary closure) — pack with moist gauze
- ✦Antibiotic therapy (therapeutic, not just prophylactic) often required
- ✦Frequent wound assessments and dressing changes
- ✦Nutrition support important — wound healing requires adequate protein and calories
Dirty / Infected
CDC Definition
Includes old traumatic wounds with retained 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 operative field before the operation.
Surgical Examples
- ✦Ruptured appendix with abscess
- ✦Perforated bowel with fecal contamination
- ✦Traumatic wound with retained foreign material or devitalized tissue
- ✦Abscess drainage (incision and drainage of infected site)
- ✦Debridement of infected wound
Nursing Implications
- ✦SSI is nearly expected — antibiotic therapy is treatment, not just prophylaxis
- ✦Wound typically left open or managed with negative pressure wound therapy (wound VAC)
- ✦Frequent wound irrigations and dressing changes
- ✦Monitor for systemic infection (fever, elevated WBC, hemodynamic instability, sepsis signs)
- ✦Nutritional support: high protein, high calorie for wound healing
- ✦Isolation precautions per specific organism if identified
Quick Reference — SSI Risk Summary
Class I
Clean
1–2%
SSI risk
Class II
Clean-Contaminated
2–10%
SSI risk
Class III
Contaminated
10–15%
SSI risk
Class IV
Dirty/Infected
>15%
SSI risk
NCLEX Pearls — Wound Classification
Related Resources
Standards & sources
Fact-checked Jun 21, 2026This page is written to align with AORN Guidelines for Perioperative Practice · American Society of Anesthesiologists (ASA). It is an educational summary, not a citation of any single document — always verify specific doses, values, and protocols against current guidelines and your facility policy. How we source content →