Classifies SSIs using CDC criteria with treatment protocols and reporting requirements. Use when identifying surgical infections, classifying SSI depth, or implementing SSI treatment.
Classifies SSIs using CDC criteria with treatment protocols and reporting requirements.
Why This Skill Exists
Surgical site infections (SSIs) are the most common healthcare-associated infection in surgical patients, occurring in 2-5% of all inpatient surgeries and up to 20% of emergency abdominal procedures. The CDC National Healthcare Safety Network (NHSN) provides the standardized surveillance definitions used for mandatory reporting in most US states. SSIs increase length of stay by 7-10 days, double the risk of ICU admission, increase 30-day readmission rates, and add $10,000-$25,000 per infection in direct costs.
CMS includes SSI rates in its Hospital-Acquired Condition Reduction Program, directly linking SSI performance to reimbursement penalties. ACS NSQIP tracks SSIs as a primary quality outcome, and the Standardized Infection Ratio (SIR) is publicly reported on CMS Hospital Compare. This skill provides the complete framework for SSI identification using CDC/NHSN criteria, classification by depth, evidence-based treatment, and mandatory reporting compliance.
Checkpoint A: Pre-Draft Intake (Mandatory)
What was the index surgical procedure and date?
相關技能
Default: [VERIFY — obtain from operative report]
When did signs of infection first appear (POD number)? Default: [VERIFY]
What are the clinical signs (erythema, drainage, dehiscence, fever, leukocytosis)? Default: [VERIFY]
Was there a prosthetic implant placed during the surgery? Default: no
What was the CDC wound classification at the time of surgery (I-IV)? Default: [VERIFY from operative report]
What organisms, if any, have been cultured? Default: cultures pending or not yet obtained
What treatment has been initiated? Default: none yet
Is the patient within the NHSN surveillance window? Default: [VERIFY]
Documents to Request
Operative report with wound classification
Preoperative and postoperative vital signs and WBC trends
Wound assessment nursing notes
Culture and sensitivity results
Imaging studies (CT, ultrasound) if deep infection suspected
Antibiotic administration record (prophylactic and therapeutic)
ACS NSQIP data collection form
Institutional infection control reporting requirements
Step 1: CDC/NHSN SSI Classification
Surveillance Window
SSIs must occur within the CDC/NHSN-defined surveillance period:
No implant: Within 30 days of the operative procedure
With implant (prosthetic valve, mesh, joint prosthesis, vascular graft): Within 90 days of the operative procedure
SSI Classification by Depth
Classification
Criteria (must meet ALL listed)
Tissue Involved
Superficial Incisional SSI
Infection within 30 days of surgery AND involves only skin and subcutaneous tissue AND at least one of: (1) purulent drainage from the incision, (2) organisms identified from aseptically obtained wound culture, (3) incision deliberately opened by surgeon due to signs of infection AND patient has at least one sign (pain/tenderness, swelling, erythema, warmth), (4) diagnosis of superficial SSI by surgeon or attending
Skin, subcutaneous tissue
Deep Incisional SSI
Infection within 30 days (or 90 if implant) AND involves deep soft tissues AND at least one of: (1) purulent drainage from the deep incision, (2) deep incision spontaneously dehisces or is deliberately opened by surgeon when patient has fever >38°C or localized pain/tenderness, (3) abscess found on direct exam, reoperation, or imaging
Fascia, muscle
Organ/Space SSI
Infection within 30 days (or 90 if implant) AND involves any part of the body deeper than the fascia/muscle that was opened or manipulated during surgery AND at least one of: (1) purulent drainage from a drain placed in the organ/space, (2) organisms identified from aseptically obtained culture of organ/space fluid or tissue, (3) abscess found on direct exam, reoperation, or imaging
Any anatomic site opened during surgery (e.g., peritoneal cavity, mediastinum)
Critical distinction: A wound culture growing skin flora (e.g., coagulase-negative Staphylococcus from a superficial swab) without clinical signs of infection does NOT meet SSI criteria. Culture alone is insufficient — clinical criteria must be met.
Step 2: Diagnostic Workup
Clinical Assessment
Finding
Implication
Next Step
Incisional erythema >2 cm from wound edge
Possible SSI; distinguish from normal postoperative erythema
Measure and document daily; obtain culture if worsening
Purulent drainage
Meets SSI criterion
Culture the drainage; assess depth
Wound dehiscence
May indicate deep SSI
Probe the wound to assess fascial integrity; CT if deep
Fever + leukocytosis + wound tenderness
Systemic response to SSI
Blood cultures, CT abdomen if deep/organ-space suspected
Fluctuance at wound site
Subcutaneous abscess
Bedside I&D vs. CT-guided drainage
Laboratory Studies
CBC with differential (WBC trend)
Blood cultures x2 (if systemic signs)
Wound culture — tissue biopsy or deep swab technique (NOT superficial wound swab)
Procalcitonin (to differentiate bacterial from other inflammatory causes)
CRP (trending marker for treatment response)
Imaging
CT with IV contrast: Standard for suspected deep incisional or organ/space SSI; identifies abscess, fluid collection, gas
Ultrasound: Useful for superficial fluid collections, seroma vs. abscess differentiation
MRI: When CT is insufficient (e.g., spinal SSI, soft tissue extent)
Step 3: Treatment by SSI Classification
Superficial Incisional SSI
Open the wound: Remove sutures/staples over the affected area
Express and culture the purulence: Send for gram stain, aerobic/anaerobic culture
Irrigate: Saline irrigation of the wound cavity
Pack open: Moist gauze packing, wound care with dressing changes Q12-24h
Antibiotics: NOT routinely required for superficial SSI managed with adequate I&D. Add oral antibiotics only if:
Cellulitis extends >2 cm from wound edge
Systemic signs (fever, leukocytosis)
Immunocompromised patient
Prosthetic implant present
Healing: By secondary intention or delayed primary closure
Deep Incisional SSI
Open the wound to the depth of infection: Explore to fascia
Assess fascial integrity: If fascia is intact, manage as deep wound infection. If fascia is disrupted (fascial dehiscence), urgent surgical consultation for re-closure
Culture deep tissue: Not surface swab
IV antibiotics: Empiric coverage targeting expected organisms per wound classification:
Source control: The priority — either percutaneous CT-guided drainage or operative washout
IV antibiotics: Broad-spectrum empiric coverage, then narrow based on culture
Repeat imaging: 48-72h after drainage to confirm adequacy
Interventional radiology consultation: For percutaneous drainage of accessible collections
Operative management: Required when percutaneous drainage is insufficient, when there is diffuse peritonitis, or when the source requires operative repair (e.g., anastomotic leak)
Step 4: Antibiotic Selection and Duration
Empiric Antibiotic Selection
SSI Type
Likely Organisms
Empiric Regimen
Clean wound
S. aureus (including MRSA), coag-neg Staph, Strep
Vancomycin ± cefazolin
Clean-contaminated (GI)
Gram-negatives, anaerobes, Enterococcus
Piperacillin-tazobactam
Contaminated/Dirty
Polymicrobial (gram-neg, anaerobes, Enterococcus)
Meropenem or piperacillin-tazobactam + vancomycin
Prosthetic implant
S. aureus, S. epidermidis, Propionibacterium
Vancomycin + rifampin (if retaining implant)
Duration Guidelines
Superficial SSI with adequate I&D, no cellulitis: No antibiotics or 5-7 days oral
Deep incisional SSI with adequate source control: 7-10 days IV, then oral step-down
Organ/space SSI with adequate source control: 4-7 days after source control (per STOP-IT trial for intra-abdominal infections)
Prosthetic implant infection: 6 weeks IV if retaining implant; consult infectious disease
Narrow antibiotics based on culture and sensitivity results. Document de-escalation rationale.
Step 5: Reporting and Prevention
Mandatory Reporting
NHSN surveillance: Report all SSIs meeting CDC criteria through the NHSN system. Include:
Surgical site hair removal by clipping (not shaving)
Shaving increases SSI risk
Normothermia maintenance (≥36°C)
Hypothermia impairs neutrophil function
Perioperative glucose control (<180 mg/dL)
Hyperglycemia impairs immune function
Supplemental oxygen
Controversial; institutional discretion
Wound protector for GI surgery
Reduces superficial SSI in contaminated cases
Checkpoint B: Post-Draft Alignment (Mandatory)
Does the SSI classification (superficial, deep, organ/space) meet CDC/NHSN criteria with all required elements documented?
Has the wound been cultured appropriately (tissue/deep technique, not superficial swab)?
Is the antibiotic regimen appropriate for the SSI type and being de-escalated based on culture data?
Has source control been achieved (drainage, debridement, or reoperation)?
Has the SSI been reported through all required systems (NHSN, NSQIP, institutional, state)?
Quality Audit
SSI identified within the NHSN surveillance window (30 or 90 days)
CDC/NHSN classification criteria met and documented
SSI depth classified (superficial, deep, organ/space) with supporting evidence
Wound culture obtained using appropriate technique (tissue biopsy or Levine)
Imaging obtained for suspected deep or organ/space SSI
Source control achieved (wound opened, abscess drained, or reoperation)
Empiric antibiotics appropriate for wound class and likely organisms
Antibiotics de-escalated based on culture and sensitivity data
Antibiotic duration documented with rationale
SSI reported to NHSN per surveillance protocol
SSI reported to ACS NSQIP as 30-day outcome
Institutional infection control notified
SSI prevention bundle compliance reviewed for the index case
Case flagged for M&M review if preventable factors identified
Guidelines
Use CDC/NHSN definitions strictly for classification and reporting — institutional definitions that differ from NHSN create data inconsistencies and audit risk.
A positive wound culture alone does NOT constitute an SSI. Clinical criteria (purulence, dehiscence with clinical signs, or abscess) must be met.
Source control is the cornerstone of SSI treatment. Antibiotics without adequate source control (drainage, debridement) will fail.
Duration of antibiotics after adequate source control should follow the STOP-IT trial principle: 4 days after source control for intra-abdominal infections is as effective as longer courses.
De-escalate antibiotics based on culture data within 48-72 hours. Prolonged broad-spectrum therapy drives resistance and C. difficile infection.
For prosthetic implant infections, involve infectious disease early — implant retention vs. removal decisions require specialized assessment.
Review the SSI prevention bundle compliance for every SSI case. If the prophylactic antibiotic was late, the wrong agent, or was extended beyond 24 hours, document the compliance failure for quality improvement.