NEWS2: The Modern Early Warning Score for Sepsis and Patient Deterioration

Mayta
May 12
4 min read

🧬 Introduction

NEWS2 is the latest advancement in a series of clinical tools aimed at identifying early signs of patient deterioration, particularly in the context of sepsis, respiratory failure, and shock. It serves not only as a bedside guide for risk stratification but also as a standardized communication and escalation tool across healthcare settings.

📚 Historical Evolution of Sepsis Scoring Systems

🔹 SIRS (1991–2016)

Defined by: Temperature, HR, RR, WBC.
High sensitivity but low specificity—over-triggering without predictive accuracy.
Used in Sepsis-1 and Sepsis-2 definitions.

🔹 SOFA (1994–present)

Assesses 6 organ systems (e.g., PaO₂/FiO₂, platelets, bilirubin, creatinine, GCS, MAP).
Core of Sepsis-3 definition: Acute ↑ in SOFA ≥2 points = sepsis.
Excellent mortality prediction, but needs labs → slower diagnosis.

🔹 qSOFA (2016)

Bedside tool: SBP ≤100 mmHg, RR ≥22, altered mentation.
High specificity, low sensitivity → may miss early sepsis.
Use: Triage flag to assess for full SOFA.

🔹 MEWS (1999)

Vitals-based: RR, HR, BP, Temp, LOC.
Precursor to NEWS.
Detects general deterioration, not sepsis-specific.

🔹 NEWS (2012)

Introduced by UK’s Royal College of Physicians.
6 physiological parameters + oxygen adjustment.
Standardized escalation thresholds.

🔹 NEWS2 (2017–present)

Adds new confusion and SpO₂ Scale 2 for CO₂-retaining patients (e.g., COPD).
Replaces NEWS as national UK standard for early warning.

📊 How to Use NEWS2: Structure and Scoring

Parameters Assessed (Each scored 0–3):

Respiratory rate
Oxygen saturation (SpO₂) – Scale 1 or 2
Air/Oxygen (room air or supplemental O₂)
Systolic BP
Pulse rate
Level of consciousness (AVPU or "C" for confusion)
Temperature

Total Score = Sum of individual scores (0–20 max)

Oxygen Saturation Scales:

Scale 1: For most patients → Target SpO₂ ≥ 96%
Scale 2: For chronic hypercapnic respiratory failure (e.g., COPD) → Target SpO₂ 88–92%

🧠 Interpretation of NEWS2 Scores

Total NEWS2 Score	Risk Level	Clinical Response
0–4	Low	Routine monitoring
Any 3 in one parameter	Medium	Inform senior clinician, consider escalation
5–6	Medium	Urgent clinical review, consider transfer to higher level of care
≥7	High	Emergency response, activate critical care outreach or ICU

🔬 Clinical Utility in Sepsis Detection

✅ Strengths:

High sensitivity (up to 96%) for identifying sepsis with NEWS2 ≥5.
Flags deterioration early, prompting timely antibiotic administration.
Universally applied across hospital and pre-hospital settings (ambulance, wards, ED).
Improved delirium detection with “C” in AVPU (confusion).
Safer for COPD patients using SpO₂ Scale 2.

❌ Limitations:

Moderate specificity (~59%) → false positives common (e.g., pain, anxiety, AF).
Not definitive for sepsis; it's a screening tool, not a diagnostic test.
May under-recognize patients with minimal vitals disturbance (e.g., elderly, immunosuppressed).

🏥 Real-World Example

Case:

RR = 24 (2 pts)
SpO₂ = 91% on room air (3 pts, Scale 1)
On O₂ = yes (2 pts)
SBP = 105 mmHg (1 pt)
HR = 98 bpm (0 pts)
Alert = yes (0 pts)
Temp = 38.4°C (1 pt)

Total NEWS2 = 9 → High Risk 🚨 → Call ICU/critical care outreach immediately

📈 Comparison Table: NEWS2 vs Other Scores

Score	Sensitivity	Specificity	Best Use
SIRS	High (~85%)	Low (~40%)	Early infection suspicion, but outdated
SOFA	Very High (~89%)	Moderate (~70%)	ICU-level mortality risk, slow to obtain
qSOFA	Low (~30–50%)	High (~95%)	Fast triage for high-risk sepsis
MEWS	Moderate	Moderate	General deterioration, non-sepsis specific
NEWS2	High (~96%)	Moderate (~59%)	Track-and-trigger sepsis alerts system

Comparison of Sepsis Scoring Systems: NEWS2 vs qSOFA vs SOFA

Feature	NEWS2	qSOFA	SOFA
Year Introduced	2017	2016	1996
Purpose	Early warning for deterioration, especially sepsis	Rapid bedside screen for high-risk sepsis	Quantify organ dysfunction, define sepsis (per Sepsis-3)
Setting	Hospital-wide (wards, ED, EMS, ICUs)	ED, pre-hospital, wards	ICU or settings where labs are available
Parameters Assessed	7 vitals (RR, SpO₂, Air/O₂, SBP, HR, Temp, AVPU/Confusion)	3: RR ≥22, SBP ≤100 mmHg, GCS <15	6 organ systems (respiratory, renal, hepatic, coagulation, CNS, CV)
Score Range	0–20	0–3	0–24 (each system scored 0–4)
Threshold for Action	≥5 = urgent review; ≥7 = emergency response	≥2 = high risk → investigate further	≥2 increase = defines sepsis (per Sepsis-3)
Need for Labs	❌ No	❌ No	✅ Yes (e.g., Cr, bilirubin, PaO₂, platelets, MAP, GCS)
Time to Apply	Fast (1–2 mins, vitals only)	Instant (30 sec, 3 criteria)	Slower (requires labs, often delayed)
Sensitivity (Sepsis Detection)	High (~96% in ward sepsis)	Low (~30–50%)	Very High (~89–97%)
Specificity (Avoid False Positives)	Moderate (~59%)	High (~95–98%)	Moderate (~70%)
Predictive Value for Mortality	Good (AUROC ~0.74–0.77)	Good in ICU settings (AUROC ~0.73)	Best among scores (AUROC ~0.74–0.90)
Use in Sepsis Definition	❌ No (screening tool)	❌ No (prognostic tool only)	✅ Yes (Sepsis-3: sepsis = infection + SOFA ↑ ≥2)
Strengths	High sensitivity, standardized, includes oxygen use, usable prehospital	Very simple, quick, high specificity	Accurate quantification of organ failure defines sepsis
Limitations	Moderate specificity, false positives common, needs consistent scoring	Misses early/mild sepsis, not sensitive	Requires full labs, slower, may delay early recognition

🧠 Summary:

NEWS2 = Best for early ward/emergency screening (high sensitivity).
qSOFA = Best for identifying high-risk patients fast (high specificity).
SOFA = Best for defining and tracking sepsis severity and organ dysfunction (most comprehensive).

🔮 Future Directions for NEWS2 Improvement

🔄 Trend Analysis:

Serial NEWS2 changes (e.g., from 3 → 6 in 2 hrs) are more predictive than static scores.

🧓 Age & Comorbidity Adjustments:

A frail elderly patient with NEWS2 = 4 may need urgent review. Future iterations might integrate the frailty index or age-adjusted thresholds.

🧪 Biomarker Integration:

Adding lactate, CRP, or procalcitonin to boost specificity.

🤖 Machine Learning Enhancements:

AI-enhanced EWS platforms already outperform static tools in pilot studies (e.g., deep learning models with AUROC ~0.95).

⚠️ Personalized Baselines:

Chronic conditions (e.g., COPD, AFib) distort scoring. Adjusting for personal norms may reduce false alarms.

🧾 Conclusion

NEWS2 stands as a critical milestone in the journey from simple vitals monitoring to dynamic, system-wide deterioration detection. While not a replacement for clinical judgment, it is an essential safety net—broadly validated, scalable, and effective in identifying sepsis and acute illness early.

Its continued success depends on education, refinement, and integration with emerging digital tools. In a future of personalized, precision medicine, NEWS2 will likely evolve into a more dynamic, AI-assisted tool tailored to each patient’s risk profile and clinical context.