Sepsis and septic shock

Surgical approach (source control)

• Principle: identify and control the source early (often within 6–12 h if feasible, immediately if life-threatening)
  • Drain pus/collections: percutaneous drainage (IR) vs open surgical drainage
  • Remove infected devices: central lines, urinary catheters, prostheses if implicated
  • Debridement: necrotising soft tissue infection (NSTI) requires urgent wide debridement, repeat “re-look” operations common
  • Resection/repair: perforated viscus, ischaemic bowel, anastomotic leak, consider stoma formation
  • Biliary sepsis: ERCP for cholangitis, cholecystostomy/cholecystectomy depending on physiology
• Intra-op priorities: minimise delay to theatre, obtain cultures (blood + source), haemostasis, avoid hypothermia, plan for ICU post-op

Anaesthetic management (typical for septic source control surgery)

• Type of anaesthesia: usually GA (often rapid sequence induction). Regional/neuraxial generally avoided in unstable septic shock, consider peripheral blocks as adjunct if coagulation allows
  • Neuraxial concerns: hypotension from sympathectomy, thrombocytopenia/coagulopathy, bacteraemia (relative contraindication)
• Airway: ETT preferred (high aspiration risk, need for controlled ventilation, high FiO2/PEEP, prolonged case). SGA rarely appropriate
• Duration: variable (30 min drainage to 3–6 h laparotomy/debridement), anticipate re-look surgery
• Pain: moderate–severe depending on procedure, multimodal analgesia with opioid titration, ketamine, paracetamol, NSAIDs often avoided in AKI/shock, consider regional (TAP/fascial plane) if safe
• Monitoring/lines: A-line early, large-bore IV access, CVC for vasopressors, consider cardiac output monitoring/echo, urinary catheter, temperature
• Induction/maintenance: haemodynamically stable induction (ketamine/etomidate commonly used, cautious propofol). Early vasopressor support (noradrenaline) and gentle ventilation strategy
  • Expect vasoplegia: induction can precipitate cardiovascular collapse—start vasopressor before/at induction if shocked
• Fluids/blood: balanced crystalloids first-line, avoid fluid overload, early blood products if haemorrhage/DIC, aim Hb appropriate to context (often transfuse if Hb &lt,70 g/L unless ongoing ischaemia/bleeding)
• Post-op: most require ICU/HDU, ongoing vasopressors, ventilation, renal support, lactate clearance monitoring

Definitions and diagnostic criteria

• Sepsis: life-threatening organ dysfunction caused by a dysregulated host response to infection
  • Operationalised as acute increase in SOFA score ≥2 from baseline in a patient with suspected/confirmed infection
• Septic shock: subset of sepsis with profound circulatory/metabolic abnormalities
  • Clinical criteria: despite adequate fluid resuscitation, requires vasopressors to maintain MAP ≥65 mmHg AND lactate &gt,2 mmol/L
• qSOFA (screening outside ICU): RR ≥22, altered mentation, SBP ≤100 (≥2 suggests high risk). Not a diagnostic tool, do not delay treatment
• Sepsis-3 emphasises organ dysfunction, older SIRS criteria are less specific but may still be encountered in exams
  • SIRS: ≥2 of T &gt,38 or &lt,36, HR &gt,90, RR &gt,20/PaCO2 &lt,4.3 kPa, WCC &gt,12 or &lt,4 or &gt,10% bands

Epidemiology and common sources

• Common sources: pneumonia, intra-abdominal sepsis (perforation, anastomotic leak), urinary tract, skin/soft tissue (cellulitis/NSTI), line-related infection
• Common organisms: Gram-negative (e.g., E. coli), Gram-positive (e.g., Staph aureus), anaerobes (abdominal), fungi (immunosuppressed/TPN/long ICU stay)
• Risk factors: extremes of age, immunosuppression, diabetes, CKD, malignancy, indwelling devices, recent surgery, burns/trauma

Pathophysiology (what drives shock and organ failure)

• Dysregulated inflammation: PAMPs/DAMPs → cytokines (TNF-α, IL-1, IL-6), complement, leukocyte activation
• Vasoplegia: NO-mediated vasodilation + relative vasopressin deficiency → low SVR, maldistributed flow
• Capillary leak and endothelial dysfunction: third spacing, oedema, reduced effective circulating volume, glycocalyx injury
• Myocardial depression: sepsis-induced cardiomyopathy (often reversible) → reduced EF, impaired diastolic function, may coexist with high CO state
• Microcirculatory dysfunction: shunting, impaired oxygen extraction, lactate may reflect stress/adrenergic drive as well as hypoperfusion
• Coagulation derangement: tissue factor activation, consumption, impaired anticoagulant pathways → DIC risk, thrombocytopenia common
• Mitochondrial dysfunction/cytopathic hypoxia: impaired cellular oxygen utilisation contributes to organ dysfunction

Clinical features and organ dysfunction

• General: fever or hypothermia, tachycardia, tachypnoea, altered mental state, mottling, oliguria, ileus
• Respiratory: hypoxaemia, ARDS (bilateral opacities, non-cardiogenic), increased work of breathing
• Cardiovascular: hypotension, wide pulse pressure early, cool peripheries late, arrhythmias (AF), myocardial ischaemia
• Renal: AKI, rising creatinine/urea, oliguria, consider obstruction and nephrotoxins
• CNS: delirium/encephalopathy, reduced GCS
• Haematology: thrombocytopenia, coagulopathy, DIC, anaemia
• Metabolic: hyperglycaemia, lactic acidosis, hypocalcaemia, adrenal insufficiency (relative)

Investigations (initial and ongoing)

• Bedside: ABG/VBG (lactate, acid-base), glucose, ECG, CXR/POCUS, urine output, temperature
• Bloods: FBC, U&amp,E/creatinine, LFTs, CRP/procalcitonin (trend), coagulation, fibrinogen, group &amp, save/crossmatch
• Microbiology: blood cultures (2 sets) before antibiotics if no delay, culture suspected source (sputum, urine, wound, line tips)
• Imaging: CT abdomen/pelvis for source, ultrasound for biliary/renal, echocardiography to assess volume status and myocardial function
• Monitoring response: lactate clearance, capillary refill time, ScvO2/SvO2 (selected), dynamic fluid responsiveness tests
  • Dynamic tests: passive leg raise with stroke volume change, pulse pressure variation (limitations with arrhythmia/low VT)

Immediate management (time-critical bundle)

• A–E approach, call for senior help early, treat hypoxia and hypotension immediately
• Oxygen/ventilation: titrate to target saturations, early intubation if airway compromise, severe work of breathing, refractory hypoxaemia, or to facilitate source control
• Cultures then antibiotics: give IV broad-spectrum antibiotics within 1 hour of recognition of sepsis/septic shock (do not delay for cultures if difficult)
  • Choose based on likely source, local guidelines, resistance risk, add MRSA/anaerobic/fungal cover when indicated, de-escalate with results
• Fluids: initial bolus commonly 30 mL/kg crystalloid in septic shock, but individualise, reassess frequently to avoid overload
  • Preferred: balanced crystalloids, avoid starches, albumin may be considered when large volumes required (unit-dependent practice)
• Vasopressors: noradrenaline first-line to target MAP ≥65 mmHg, start early (even peripherally via a large-bore cannula while securing CVC, with close monitoring)
  • Add vasopressin (fixed dose) if escalating noradrenaline, adrenaline as alternative/add-on, consider angiotensin II where available
  • Inotrope: dobutamine if myocardial dysfunction with persistent hypoperfusion despite adequate MAP/volume
• Source control: urgent surgical/IR intervention when indicated, remove infected lines, drain collections
• Steroids: consider hydrocortisone 200 mg/day (e.g., 50 mg QDS or infusion) if shock remains refractory to fluids + vasopressors
• Glycaemic control: avoid severe hyperglycaemia, typical target 6–10 mmol/L (avoid hypoglycaemia)
• VTE prophylaxis and stress ulcer prophylaxis: assess bleeding risk, LMWH + mechanical prophylaxis, PPI/H2 blocker if risk factors

Anaesthetic considerations in septic shock (FRCA focus)

• Pre-op optimisation: resuscitate in ED/ICU if possible but do not delay urgent source control, ensure antibiotics given, correct hypoglycaemia, severe hyperkalaemia, and treat arrhythmias
• Induction strategy: high risk of peri-induction collapse due to vasodilation + relative hypovolaemia + myocardial depression
  • Consider: ketamine or etomidate, reduce induction dose, opioid sparing initially, have vasopressor boluses ready (metaraminol/phenylephrine/adrenaline as appropriate)
  • RSI: aspiration risk (ileus, reduced GCS), use rocuronium, consider sugammadex availability, cricoid pressure per local practice
• Ventilation: lung-protective strategy if ARDS risk (VT ~6 mL/kg PBW, plateau pressure &lt,30 cmH2O), appropriate PEEP, permissive hypercapnia if tolerated
• Haemodynamics: aim MAP ≥65 (higher if chronic HTN/cerebrovascular disease), use echo to guide fluids/inotropes, avoid chasing CVP alone
• Renal protection: avoid nephrotoxins, maintain perfusion, adjust drug doses, consider early RRT in refractory acidosis/hyperkalaemia/fluid overload/uraemia
• Coagulation: check platelets/INR/fibrinogen, anticipate DIC, use blood products guided by labs/TEG/ROTEM where available
• Temperature: active warming, hypothermia worsens coagulopathy and outcomes
• Analgesia/sedation: opioid sensitivity may be altered, consider ketamine infusion, avoid excessive benzodiazepines, daily sedation breaks in ICU where appropriate

ICU management overview

• Ongoing resuscitation: repeated assessment of perfusion (mental state, urine output, lactate trend, capillary refill) and fluid responsiveness
• Vasopressor strategy: noradrenaline first-line, add vasopressin, consider adrenaline, consider inotrope if low cardiac output
• Ventilation: ARDSnet principles, prone positioning if severe ARDS, conservative fluid strategy once shock resolved
• Renal: CRRT commonly used in unstable patients, manage fluid balance and electrolytes
• Antibiotic stewardship: daily review, de-escalation, stop if infection excluded, therapeutic drug monitoring (e.g., vancomycin/aminoglycosides)
• Nutrition: early enteral feeding if feasible, avoid overfeeding, consider refeeding risk

Special situations

• Neutropenic sepsis: medical emergency—broad-spectrum antibiotics immediately (per local policy), consider antifungal if persistent fever, isolate and involve haematology
• Pregnancy: maintain uteroplacental perfusion, left lateral tilt, early senior obstetric/ICU involvement, antibiotics safe in pregnancy per guidance
• Paediatrics: different physiology and thresholds, use paediatric sepsis guidance, early senior help
• Perioperative sepsis: consider anastomotic leak, intra-abdominal collection, line infection, early CT and source control

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