Sepsis and Surgical Site Infection — Bundle

Sepsis is a life-threatening organ dysfunction caused by a dysregulated host response to infection. It is a leading cause of preventable death in hospitalised patients and is a significant risk in orthopaedic surgery — particularly following prosthetic joint implantation, fracture fixation, and debridement procedures. Surgical site infection (SSI) is a distinct but related entity: a postoperative infection of the surgical incision or deeper tissues, occurring within 30 days of surgery (or within 1 year if a prosthetic implant is left in place). Every orthopaedic surgeon must understand the definition, recognition, and management of sepsis, and must know the bundle-based approach to SSI prevention that forms the foundation of modern perioperative care.

• Sepsis-3 definitions (Singer et al., JAMA 2016): (1) Sepsis = life-threatening organ dysfunction caused by a dysregulated host response to infection; diagnosed by a SOFA (Sequential Organ Failure Assessment) score increase of ≥2 points from baseline in a patient with suspected or confirmed infection; (2) Septic shock = a subset of sepsis with circulatory, cellular, and metabolic abnormalities substantially increasing mortality; diagnosed clinically by persistent hypotension requiring vasopressors to maintain MAP ≥65 mmHg PLUS serum lactate >2 mmol/L despite adequate fluid resuscitation; (3) Sepsis-3 deliberately removed `SIRS criteria` (systemic inflammatory response syndrome — formerly used to diagnose sepsis) from the definition because SIRS is non-specific and can occur in non-infectious conditions; however, SIRS criteria (temperature >38°C or <36°C; HR >90; RR >20; WBC >12 or <4) remain clinically useful as early screening indicators
• qSOFA (quick SOFA) screening tool: a 3-item bedside tool for early identification of patients at risk of sepsis outside the ICU; score 1 point each for: (1) altered mental status (GCS <15); (2) respiratory rate ≥22; (3) systolic BP ≤100 mmHg; qSOFA ≥2 = high risk of poor outcome from infection → prompt escalation, full SOFA assessment, and sepsis bundle activation; qSOFA is NOT diagnostic of sepsis but is a rapid bedside screening tool

• The Sepsis Six: a bundle of six time-critical interventions to be completed within 1 hour of suspecting sepsis (`the golden hour`); completion of all six within 1 hour has been shown to reduce sepsis mortality by approximately 50%; the six elements are: (1) Administer high-flow oxygen (15 L/min via non-rebreathe mask) — target SpO2 ≥94%; (2) Take blood cultures (minimum 2 sets from 2 different sites before administering antibiotics); (3) Administer IV antibiotics (broad-spectrum according to local protocol and suspected source — within 1 hour of sepsis recognition); (4) Measure serum lactate (lactate ≥2 mmol/L = evidence of tissue hypoperfusion; lactate ≥4 mmol/L = high-risk septic shock); (5) Administer IV fluids (500 mL crystalloid — 0.9% NaCl or Hartmann`s solution — over 15 minutes if lactate ≥2 mmol/L or signs of hypoperfusion; reassess after each bolus; avoid excessive fluid resuscitation — target urine output ≥0.5 mL/kg/hour); (6) Measure urine output (catheterise if not already done; aim for ≥0.5 mL/kg/hour; oliguria = indicator of organ dysfunction)
• Antibiotic stewardship: the antibiotic agent chosen for the Sepsis Six should be: (1) broad-spectrum covering likely causative organisms; (2) appropriate for the suspected source (skin/wound = Staphylococcus aureus; urinary tract = gram-negatives; respiratory = respiratory flora); (3) consistent with local microbiological resistance patterns (consult local antibiogram/pharmacy); (4) de-escalated as soon as culture and sensitivity results are available; in orthopaedic patients, IV co-amoxiclav or piperacillin-tazobactam (Tazocin) ± teicoplanin/vancomycin for MRSA cover are common empirical choices depending on the source

• Pre-operative measures: MRSA screening and decolonisation (mupirocin nasal ointment + chlorhexidine body wash × 5 days for carriers); blood glucose optimisation (HbA1c <7.5–8.5% before elective arthroplasty — hyperglycaemia impairs neutrophil function and wound healing); smoking cessation (at least 4–6 weeks before elective surgery); nutritional optimisation (albumin <35 g/L = increased SSI risk — delay elective surgery for nutritional optimisation); weight management (BMI >40 = substantially increased SSI risk — consider delay for weight loss before elective arthroplasty); pre-operative chlorhexidine skin wash on the night before and morning of surgery
• Intraoperative measures: correct antibiotic prophylaxis timing and dosing (within 60 minutes of incision; repeat if surgery >2× antibiotic half-life; stop within 24 hours); chlorhexidine-alcohol skin preparation (superior to betadine — Darouiche NEJM 2010); laminar flow theatre + body exhaust suits for arthroplasty; minimise theatre traffic and door openings; gentle tissue handling; minimise haematoma (meticulous haemostasis, drains for selected cases); avoid hypothermia (maintain core temp >36°C intraoperatively — hypothermia impairs neutrophil function); normoglycaemia intraoperatively; wound irrigation (povidone-iodine or dilute chlorhexidine irrigation before closure — increasingly used; growing evidence base); antibiotic-loaded bone cement for cemented arthroplasty
• Post-operative measures: wound inspection at 48–72 hours; keep dressing dry and intact; early ambulation and physiotherapy (reduces DVT, pneumonia, and pressure sores — indirect SSI risk reducers); glycaemic control post-operatively; appropriate post-operative antibiotic duration (24 hours maximum for prophylaxis; longer only if therapeutic antibiotics are indicated); remove drains within 24–48 hours (each day of drain = increased infection risk); educate patient on wound care after discharge; clear instructions on when to seek medical attention (wound redness, discharge, fever)

• DAIR (Debridement, Antibiotics, and Implant Retention): the preferred surgical management for early acute PJI (<4 weeks of symptom onset) with a stable, well-fixed implant; procedure: thorough surgical debridement of all infected tissue; extensive joint washout; exchange of all modular components (femoral head, acetabular liner in hip; tibial insert in knee — biofilm not on the fixed components); intraoperative samples for MC&S (5–6 samples); IV antibiotics started peri-operatively and continued for 6–12 weeks followed by oral suppressive therapy; the critical success factors for DAIR are: early intervention (symptoms <4 weeks), stable implant fixation (not loose), susceptible organism (NOT Staphylococcus epidermidis/MRSA with high biofilm production — these are more likely to fail DAIR), and no sinus tract
• Two-stage revision arthroplasty: the gold standard for established PJI (symptoms >4 weeks) or failed DAIR; Stage 1 — complete removal of all prosthetic components + thorough debridement + antibiotic-loaded cement spacer (static or mobile-bearing); microbiological samples; IV antibiotics tailored to the causative organism; Stage 2 — after clinical, biochemical (CRP, ESR normalised), and if needed microbiological evidence of infection clearance (typically 6–12 weeks) — re-implantation of a new prosthesis; the two-stage approach has cure rates of approximately 90%; one-stage revision (removing the infected prosthesis and re-implanting at the same operation) is increasingly used in selected cases with specific criteria

• Sepsis-3 definition: life-threatening organ dysfunction from dysregulated host response to infection; SOFA score ≥2; Septic shock = vasopressors + MAP ≥65 mmHg + lactate >2 mmol/L despite fluids
• qSOFA: 3 criteria — altered mental status, RR ≥22, SBP ≤100; score ≥2 = high risk → escalate; bedside screening tool (not diagnostic)
• Sepsis Six (within 1 hour): (1) High-flow O2; (2) Blood cultures ×2; (3) IV broad-spectrum antibiotics; (4) Serum lactate; (5) IV fluid bolus (500 mL crystalloid); (6) Catheterise + measure urine output; completion of all 6 within 1 hour = 50% mortality reduction
• SSI classification: superficial (skin/subcut — above fascia — antibiotics ± drainage); deep incisional (fascia/muscle — debridement ± DAIR if implant); organ/space (joint/implant — DAIR or two-stage revision)
• DAIR criteria: early PJI (<4 weeks); stable well-fixed implant; susceptible organism (avoid for high-biofilm Staph epidermidis/MRSA); no sinus tract; modular component exchange (head/liner) is mandatory; success rate 60–80% in optimal cases
• Two-stage revision: gold standard for established PJI; Stage 1 = remove implant + debride + antibiotic spacer; Stage 2 = re-implantation after 6–12 weeks when infection cleared; cure rate ~90%
• SSI prevention bundle: pre-op MRSA decolonisation + chlorhexidine wash + glucose optimisation + smoking cessation; intraoperative antibiotic prophylaxis within 60 min + laminar flow + chlorhexidine-alcohol skin prep + normothermia + normoglycaemia; post-op early wound inspection + drain removal <48 hours + glycaemic control
• Antibiotic prophylaxis timing: within 60 minutes of skin incision (30 minutes for vancomycin); the antibiotic must be in the tissues AT the time of incision; repeat if surgery >2× half-life; stop within 24 hours