Sepsis and septic shock

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Quick Overview

Sepsis is a life-threatening organ dysfunction caused by dysregulated host response to infection (qSOFA ≥2 or SOFA increase ≥2). Septic shock is sepsis with persisting hypotension requiring vasopressors (MAP ≥65 mmHg) and lactate >2 mmol/L despite adequate fluid resuscitation. NICE NG51 emphasizes early recognition, immediate treatment within 1 hour, and the Sepsis Six bundle to reduce mortality from 30-50% to <20%.

Core Facts & Concepts

🎯 Definitions & Thresholds

  • Sepsis: Suspected/confirmed infection + organ dysfunction (qSOFA ≥2 or NEWS2 ≥5)
  • Septic shock: Sepsis + lactate >2 mmol/L + persistent hypotension (MAP <65 mmHg) despite 30 mL/kg fluid resuscitation
  • Red flag lactate: >2 mmol/L warrants immediate senior review; >4 mmol/L indicates high mortality risk

📊 Recognition Criteria

ToolParametersThreshold
qSOFARespiratory rate ≥22, Altered mentation, SBP ≤100≥2 = organ dysfunction
NEWS2Vital signs scoring system≥5 = key threshold; 3 in single parameter = urgent
SOFA6 organ systems scored 0-4Increase ≥2 = sepsis

Figure 1: Blood test results showing elevated lactate at 4.2 mmol/L with metabolic acidosis

💊 Antimicrobial Timing

  • Within 1 hour of recognition for suspected sepsis (NICE NG51)
  • Empirical broad-spectrum antibiotics guided by local policy
  • Blood cultures before antibiotics (but don't delay >45 minutes)

💧 Fluid Resuscitation

  • Initial bolus: 500 mL crystalloid over <15 minutes
  • Target: 30 mL/kg within first 3 hours for septic shock
  • Reassess after each bolus: BP, heart rate, capillary refill, urine output, lactate

Problem-Solving Approach

🔴 The Sepsis Six (Within 1 Hour)

  1. Give oxygen: Target SpO₂ 94-98% (88-92% if COPD risk)
  2. Take blood cultures: Minimum 2 sets (aerobic + anaerobic) from different sites
  3. Give IV antibiotics: Broad-spectrum, within 1 hour of recognition
  4. Give IV fluids: 500 mL crystalloid bolus if lactate ≥2 mmol/L or SBP <90 mmHg
  5. Measure lactate: Arterial/venous blood gas; repeat within 6 hours
  6. Measure urine output: Catheterize if shocked; target >0.5 mL/kg/hour

Figure 2: Chest X-ray showing bilateral patchy infiltrates in patient with septic pneumonia

🚩 Red Flags Requiring ICU Referral

  • Lactate >4 mmol/L despite initial resuscitation
  • Requiring vasopressors to maintain MAP ≥65 mmHg
  • Respiratory failure needing mechanical ventilation
  • Reduced conscious level (GCS <12)
  • Oliguria (<0.5 mL/kg/hour) despite fluid challenge

💉 Vasopressor Initiation

  • Start noradrenaline if MAP <65 mmHg after 30 mL/kg fluid bolus
  • Target MAP ≥65 mmHg (may need higher in chronic hypertension)
  • Requires central venous access and ICU-level monitoring

Analysis Framework

🔍 Sepsis vs. Other Shock States

FeatureSeptic ShockCardiogenic ShockHypovolemic Shock
LactateElevated (>2)ElevatedElevated
SkinWarm peripheries (early)Cold, clammyCold, clammy
JVPLow/normalRaisedLow
Fluid responseInitial improvementWorsensImproves
SourceInfection focusCardiac pathologyBlood/fluid loss

⚖️ qSOFA vs. NEWS2 (NICE NG51 Position)

  • NEWS2 preferred in UK hospitals for risk stratification
  • qSOFA useful in pre-hospital/resource-limited settings
  • NEWS2 more sensitive; qSOFA more specific for mortality prediction
  • Use clinical judgment alongside scoring tools

Visual Aid

⏱️ Critical Timeframes

ActionTimeframe
Antibiotics from recognition1 hour
Initial fluid bolus<15 minutes
30 mL/kg fluids in shock3 hours
Lactate remeasurement6 hours
Senior review if lactate >2Immediate

Key Points Summary

Sepsis = infection + organ dysfunction (qSOFA ≥2 or NEWS2 ≥5); septic shock adds lactate >2 mmol/L + persistent hypotension despite fluids

Sepsis Six within 1 hour: Oxygen, blood cultures, IV antibiotics, IV fluids, lactate measurement, urine output monitoring

Antimicrobials within 1 hour of recognition (NICE NG51) - blood cultures first, but don't delay antibiotics >45 minutes

Fluid resuscitation: 500 mL crystalloid bolus if lactate ≥2 or SBP <90; target 30 mL/kg in first 3 hours for septic shock

Vasopressors (noradrenaline) if MAP <65 mmHg after 30 mL/kg fluids; requires ICU-level care

Lactate thresholds: >2 mmol/L = senior review; >4 mmol/L = high mortality risk; repeat at 6 hours to assess response

Common pitfall: Delaying antibiotics for investigations - treat first, investigate simultaneously; every hour delay increases mortality by 7-8%

Practice Questions: Sepsis and septic shock

Test your understanding with these related questions

A 55-year-old man presents with acute severe abdominal pain and hypotension. He takes warfarin for atrial fibrillation. CT shows large retroperitoneal hematoma. His INR is 7.5. What is the most appropriate immediate management?

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Flashcards: Sepsis and septic shock

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_____ should be given in addition to dual antiplatelet therapy in NSTEMI patients who are not at a high risk of bleeding/ having angiography immediately

TAP TO REVEAL ANSWER

_____ should be given in addition to dual antiplatelet therapy in NSTEMI patients who are not at a high risk of bleeding/ having angiography immediately

Fondaparinux

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