At what National Early Warning Score (NEWS) or Modified Early Warning Score (MEWS) threshold should a patient be treated as potentially septic and what immediate interventions are recommended for the sepsis response bundle?

NEWS2 Thresholds and Sepsis Response Bundle for Suspected Sepsis

Use NEWS2 ≥5 as the threshold to trigger systematic sepsis screening and initiate the sepsis response bundle, with antibiotic timing and monitoring frequency determined by the specific risk tier (moderate risk at 5-6, high risk at ≥7). 1

NEWS2 Risk Stratification Framework

The 2024 NICE guideline establishes NEWS2 as the primary risk stratification tool, replacing qSOFA for initial sepsis screening in acute care settings. 1, 2

Risk Categories and Clinical Actions

High Risk (NEWS2 ≥7):

• Re-calculate NEWS2 every 30 minutes 1
• Administer broad-spectrum IV antibiotics within 1 hour of risk assessment 1, 2
• Immediate senior clinician review (FY2 level or above) 1
• Consider ICU-level care 2
• Obtain at least 2 sets of blood cultures before antibiotics 3
• Initiate rapid crystalloid bolus ≥20 mL/kg (approximately 1.5-2 L) 2
• Measure serum lactate immediately 2

Moderate Risk (NEWS2 5-6):

• Re-calculate NEWS2 every hour 1
• Administer antibiotics within 3 hours 1, 2
• Escalate to experienced clinician for assessment 1
• Blood cultures and lactate measurement 3

Low Risk (NEWS2 1-4):

• Re-calculate NEWS2 every 4-6 hours 1
• Administer antibiotics within 6 hours 1
• Continue monitoring per protocol 1

Very Low Risk (NEWS2 0):

• Routine monitoring protocol 1
• No immediate escalation required 2

Critical Override Criteria

Immediately escalate to high-risk management regardless of NEWS2 score if any of the following are present: 1, 3

• Mottled or ashen skin appearance
• Non-blanching petechial or purpuric rash
• Cyanosis of skin, lips, or tongue
• Any single NEWS2 parameter scoring 3 points (e.g., respiratory rate <8 or ≥25/min, SpO₂ <91%, systolic BP <90 mmHg) 1, 2

Immediate Sepsis Response Bundle

Within First Hour (High-Risk Patients):

1. Obtain blood cultures (at least 2 sets, aerobic and anaerobic) before antibiotics 3

2. Measure serum lactate to assess tissue hypoperfusion 2, 3

3. Administer broad-spectrum IV antibiotics within 1 hour 1, 2

   • For intra-abdominal sources: piperacillin-tazobactam 4.5g IV or carbapenem + metronidazole 2
   • Adjust for renal impairment but do not delay initial dose 2

4. Initiate fluid resuscitation with crystalloid bolus ≥20 mL/kg 2

   • Target MAP ≥65 mmHg 2
   • Use dynamic assessments of fluid responsiveness 2
   • Avoid excessive crystalloid in intra-abdominal infections (risk of bowel edema and abdominal compartment syndrome) 2

5. Identify and control infection source urgently 1, 2

   • Surgical consultation for source control within 24 hours if indicated 2

Ongoing Management:

• Serial NEWS2 monitoring at intervals defined by risk category to track trajectory 1
• Vasopressor initiation (norepinephrine first-line) if hypotension persists despite adequate fluid resuscitation 2
• ICU transfer if vasopressors needed or lactate >2 mmol/L after resuscitation 2
• Antibiotic review within 1 hour of microbiological results, narrowing spectrum when appropriate 1

Common Pitfalls and Caveats

Interpretation Context: 1, 3

• Always interpret NEWS2 in context of baseline physiology and comorbidities
• Patients with chronic heart/lung disease or spinal injury may have altered baseline parameters 2
• Clinical deterioration or lack of response to interventions indicates higher actual risk than NEWS2 alone suggests 1

Timing Errors: 1

• The antibiotic timeframes (1 hour, 3 hours, 6 hours) are maximum windows, not targets to work toward
• Do not delay antibiotics beyond 1 hour in high-risk patients 2

MEWS Limitations: 4, 5

• MEWS has lower predictive accuracy (AUC 0.73) compared to NEWS2 (AUC 0.89-0.93) for sepsis detection 4, 6
• The 2024 NICE guideline has formally discontinued qSOFA and MEWS as primary screening tools in favor of NEWS2 2

Fluid Management: 2

• Titrate crystalloid carefully to avoid fluid overload, especially in intra-abdominal infections
• Several liters may be required within first 24-48 hours, but use dynamic assessments

Adjunctive Biomarkers

While NEWS2 drives initial decision-making, consider these laboratory markers: 3

• Procalcitonin ≥1.5 ng/mL: 100% sensitivity, 72% specificity for sepsis
• CRP ≥50 mg/L: 98.5% sensitivity, 75% specificity
• Lactate >1 mmol/L: indicates tissue hypoperfusion; serial measurements guide resuscitation