# health.news2

Status: needs review and sign-off by a qualified clinician before it is published. Not a medical device; for decision support only; always follow local clinical guidelines.

The National Early Warning Score 2 for one set of adult observations. Each of
the six physiological parameters is scored from the Royal College of
Physicians' chart 1, 2 is added when the patient needs supplemental oxygen,
and the sum is the aggregate NEW score. The clinical risk band comes from
chart 2:

| NEW score | Clinical risk |
|---|---|
| aggregate 0-4 | low |
| a score of 3 in any single parameter (a "red score") | low-medium |
| aggregate 5-6 | medium |
| aggregate 7 or more | high |

The bands are checked in the order high, medium, red score, low: a red score
raises a low aggregate to low-medium, but an aggregate of 5 or more already
outranks it. `redScore` is returned separately because the RCP asks for an
urgent ward-based review for any red score, whatever the band. The oxygen
weighting (2) can never be a red score on its own.

## The scoring (RCP chart 1)

| Parameter | 3 | 2 | 1 | 0 | 1 | 2 | 3 |
|---|---|---|---|---|---|---|---|
| Respiration rate /min | ≤8 | | 9-11 | 12-20 | | 21-24 | ≥25 |
| SpO2 scale 1 % | ≤91 | 92-93 | 94-95 | ≥96 | | | |
| SpO2 scale 2 % | ≤83 | 84-85 | 86-87 | 88-92, or ≥93 on air | 93-94 on oxygen | 95-96 on oxygen | ≥97 on oxygen |
| Air or oxygen | | oxygen | | air | | | |
| Systolic BP mmHg | ≤90 | 91-100 | 101-110 | 111-219 | | | ≥220 |
| Pulse /min | ≤40 | | 41-50 | 51-90 | 91-110 | 111-130 | ≥131 |
| Consciousness | | | | alert | | | new confusion, voice, pain, unresponsive |
| Temperature °C | ≤35.0 | | 35.1-36.0 | 36.1-38.0 | 38.1-39.0 | ≥39.1 | |

## Things a caller must get right

- **SpO2 scale 2 is only for patients with confirmed hypercapnic (type 2)
  respiratory failure, on the direction of a competent clinical decision
  maker** (RCP report, paragraphs 25-26). On scale 2 a high saturation while
  on oxygen scores up to 3, because over-oxygenation is the danger; on air it
  scores 0. Scoring such a patient on scale 1 under-scores them.
- **NEWS2 is for adults aged 16 or over and not in pregnancy** (RCP report,
  paragraph 2). This function cannot see age or pregnancy; the caller must
  not use it for children or pregnant women.
- **New confusion** (`confusion`, the C of ACVPU) means new-onset confusion,
  disorientation or delirium, and scores 3 like voice, pain or unresponsive.
- **Temperature** is compared "at or below" each chart row, so a value
  between two one-decimal rows (35.05) scores with the higher row (35.1-36.0,
  score 1). Thermometers record one decimal place.
- The other observations are whole numbers, as charted.

## Input guard rails (not from the RCP)

Out-of-range values are errors, never clamped, so a unit or typing mistake
(98.6 for a Celsius temperature, a pulse of 700) cannot quietly produce a
score. The ranges are the implementation's own and need clinical sign-off:
respiration rate 1-80 /min, SpO2 1-100 %, systolic BP 20-300 mmHg, pulse
1-300 /min, temperature 25.0-45.0 °C, SpO2 scale 1 or 2, consciousness one of
`alert`, `confusion`, `voice`, `pain`, `unresponsive`.

## Source

Royal College of Physicians. *National Early Warning Score (NEWS) 2:
Standardising the assessment of acute-illness severity in the NHS.* Updated
report of a working party. London: RCP, 2017. Chart 1 "The NEWS scoring
system" and chart 2 "NEWS thresholds and triggers",
https://www.rcp.ac.uk/improving-care/resources/national-early-warning-score-news-2/
. The vectors were worked out by hand from those two charts; the RCP
publishes no numeric worked examples.