news2 oxygen saturation scales

NEWS2 Oxygen Saturation Scales

The National Early Warning Score 2 (NEWS2) is a standardised clinical assessment tool developed by the Royal College of Physicians to identify patients at risk of clinical deterioration. One of the key enhancements introduced with NEWS2 was the addition of two separate oxygen saturation (SpO₂) scoring scales, allowing more appropriate assessment of patients with different respiratory conditions.

Most patients are assessed using Oxygen Saturation Scale 1, while Scale 2 is reserved for a specific group of patients with confirmed hypercapnic respiratory failure who require lower target oxygen saturation levels. Selecting the correct scale is essential for accurate NEWS2 scoring and safe patient management.

NEWS2 Oxygen Saturation Scale 1

Scale 1 is the standard oxygen saturation scale used for the vast majority of adult patients.

It applies to patients who have normal oxygen saturation targets and do not have confirmed hypercapnic respiratory failure. Oxygen saturation measurements are scored according to predefined NEWS2 thresholds, with lower oxygen saturations contributing progressively higher NEWS2 scores.

Scale 1 is appropriate for most patients presenting with:

  • Pneumonia
  • Sepsis
  • Heart failure
  • Asthma
  • Pulmonary embolism
  • Trauma
  • Acute medical illness

NEWS2 Oxygen Saturation Scale 2

Scale 2 was introduced specifically for patients with confirmed hypercapnic respiratory failure who have a prescribed target oxygen saturation range of 88–92%. These patients require careful oxygen administration because excessive oxygen therapy may worsen carbon dioxide retention and respiratory acidosis.

Examples of patients who may require Scale 2 include:

  • Confirmed chronic hypercapnic respiratory failure
  • Selected patients with severe chronic obstructive pulmonary disease (COPD)
  • Other conditions where a clinician has prescribed an oxygen target of 88–92%

Importantly, Scale 2 should only be used when a competent clinical decision-maker has determined that it is appropriate, typically following confirmation of hypercapnic respiratory failure, and that decision should be documented. It should not be applied automatically to every patient with COPD.

Why Two Oxygen Saturation Scales?

The original NEWS scoring system used a single oxygen saturation scale for all patients. However, clinicians recognised that this approach could encourage excessive oxygen administration in patients with chronic hypercapnic respiratory failure.

NEWS2 introduced Scale 2 to allow these patients to be monitored using their appropriate oxygen saturation targets while still benefiting from the early warning system. This change improves patient safety and supports evidence-based oxygen therapy.

Oxygen Therapy and NEWS2

In addition to recording oxygen saturation, NEWS2 also records whether the patient is receiving supplemental oxygen. Patients receiving oxygen therapy receive additional NEWS2 points regardless of their oxygen saturation because the need for supplemental oxygen itself reflects increased physiological risk. NEWS2 also recommends documenting both the oxygen delivery device and flow rate when oxygen is administered.

Clinical Applications

NEWS2 Oxygen Saturation Scales are used throughout healthcare, including:

  • Emergency Departments
  • Acute Medical Units
  • Hospital wards
  • Intensive Care Units
  • Ambulance services
  • Community assessment teams

Serial NEWS2 observations help clinicians identify patients whose condition is improving or deteriorating, allowing timely escalation of care.

Clinical Interpretation

NEWS2 should always be interpreted as part of a comprehensive clinical assessment. The oxygen saturation score is only one component of the overall NEWS2 score, which also incorporates:

  • Respiratory rate
  • Heart rate
  • Systolic blood pressure
  • Temperature
  • Level of consciousness
  • Supplemental oxygen use

A high NEWS2 score does not establish a diagnosis but identifies patients who require prompt clinical review and possible escalation of care. Likewise, a low score should never override significant clinical concern.

At MediCalc, the NEWS2 Oxygen Saturation Scale calculator is based on the published NEWS2 guidance and is designed to help healthcare professionals select the appropriate oxygen saturation scale and calculate NEWS2 scores accurately. It should always be used alongside current clinical guidelines, local protocols, and professional clinical judgement.