National Early Warning Score (NEWS) 1 vs NEWS 2
NEWS2 is the current standard scoring system that replaced NEWS1, with the key difference being the addition of a separate oxygen saturation scale (SpO2 scale 2) specifically for patients with type 2 respiratory failure who require adjusted target saturations of 88-92%. 1
Core Structural Differences
Oxygen Saturation Measurement
The most clinically significant change between NEWS1 and NEWS2 is how oxygen saturation is scored:
NEWS2 includes two SpO2 scales 1:
- Scale 1: Standard scale for most patients (target SpO2 ≥96%)
- Scale 2: Adjusted scale for patients with hypercapnic respiratory failure (target SpO2 88-92%)
NEWS1 used only a single oxygen saturation scale for all patients
Additional Parameter
NEWS2 explicitly includes whether the patient is on room air or supplemental oxygen as a scored parameter, which receives 2 points if the patient requires oxygen 1. This helps identify patients who are maintaining adequate saturations only because of oxygen supplementation.
Clinical Application
When to Use Each Scale
Use SpO2 Scale 2 in NEWS2 for patients with:
- Confirmed type 2 respiratory failure (hypercapnic)
- Known CO2 retention
- Conditions like severe COPD where lower oxygen targets are appropriate
Use SpO2 Scale 1 (standard) for all other patients 1
Risk Stratification (Same for Both)
Both scoring systems use the same aggregate score interpretation 1:
- 0: Very low risk
- 1-4: Low risk
- 5-6: Moderate risk
- ≥7: High risk
- Any single parameter = 3: Warrants immediate clinical concern
Evidence on Clinical Performance
Research examining NEWS2's new SpO2 scale shows mixed results on whether it improves predictive accuracy. A prospective study of 886 rapid response team patients found that applying the new SpO2 scale to the 104 patients with confirmed type 2 respiratory failure did not improve discrimination for either immediate adverse outcomes (AUROC remained 0.73) or in-hospital mortality (AUROC remained 0.68) 2.
However, NEWS2 remains the endorsed standard per 2024 NICE guidance and the Academy of Medical Royal Colleges 1. The theoretical advantage is preventing inappropriate oxygen administration in hypercapnic patients by recognizing that SpO2 88-92% is acceptable in this population.
Important Clinical Caveats
Always interpret NEWS2 scores in context 1:
- Consider underlying physiology and comorbidities
- Recognize that clinical deterioration may occur despite stable scores
- A score of 3 in any single parameter may indicate increased risk even if aggregate score is low
- Certain clinical signs (mottled/ashen appearance, non-blanching rash, cyanosis) should trigger high-risk evaluation regardless of NEWS2 score
The practical impact: NEWS2's dual oxygen saturation scales primarily prevent over-treatment with oxygen in patients with chronic hypercapnia, rather than dramatically improving mortality prediction compared to NEWS1.