Definitions relating to the National Early Warning Score 2 used in the study
| Term | Definition |
|---|---|
| Observation | Set of vital signs recorded at the bedside. Taken together, each set is amalgamated to the NEWS2 score. |
| Vital sign score | Indicates how far each vital sign deviates from a set normal range, calculated at collection of each observation with a weighting of 0–3. |
| NEWS2 score | NEWS2 was published by the RCP in 2017 and mandated for use across the NHS in the UK. NEWS2 is an aggregate early warning score. NEWS2 is a continuous variable from a minimum score of 0 to a maximum of 20. |
| Scale 1 | Oxygen target scale for NEWS2: for use in patients with no evidence of type 2 respiratory failure. Target saturations 94%–98%. |
| Scale 2 | Oxygen target scale for NEWS2: for use in patients with evidence of type 2 respiratory failure; used in all patients with diagnosis of COPD in line with clinical practice. Target saturations 88%–92%. |
| Cut points | NEWS2 scores at which certain actions are advised as per the protocol published by the RCP: NEWS2 score of 5 or more: Minimum hourly observations; registered nurse to immediately inform medical team and request urgent assessment within 1 hour by a clinician with core competencies in care of acutely ill patients; provide clinical care in an environment with monitoring facilities. NEWS2 score of less than 5 but a single score of 3 in any one category: Separate category in original scoring protocol but clinically treated the same as a score of 5 or 6. NEWS2 score of 7 or more: Continuous monitoring of vital signs; registered nurse to inform registrar or above in medical team; emergency assessment within 30 minutes by team with critical care competencies and advanced airway management skills; consider transfer to level 2 or 3 area with clinical care in an environment with monitoring facilities. |
COPD = National Early Warning Score 2; RCP = Royal College of Physicians.