Sepsis and septic shock

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

💊 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

🚩 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

⚖️ 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

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%