Introduction Early Warning Scoring systems (EWS) identify critical illness at an early stage. The Royal College of Physicians has proposed use of a ‘National Early Warning Score’ (NEWS) across UK hospitals. The NEWS allocates EWS points for oxygen saturation <96% (see Table) and does not take account of target oxygen saturation range which should be set for each patient according to the BTS oxygen guidelines. This is particularly important for patients at risk of hypercapnic respiratory failure (T2RF) who are safest with a target range of 88–92% or less. We compared the NEWS with a proposed alternative based on the Salford Royal Hospital EWS system (AltNEWS, see Table) to identify how many patients with COPD would be placed at risk of hyperoxaemia using the NEWS system.
Methods We calculated EWS scores using the NEWS and AltNEWS for 108 unselected acute medical patients at a single time point.
Results 34/108 general medical patients (31%) had risk factors for T2RF (30 COPD, 4 obstructive sleep apnoea). Nineteen of these 34 patients had saturations within their target range of 88–92% either on air or oxygen. The NEWS system allocated these patients 2 or 3 EWS points for “low” oxygen levels which could prompt nursing staff to increase supplemental oxygen, potentially precipitating dangerous hypercapnia. Three of these 34 patients had saturations >92% on oxygen. The NEWS did not alert nursing staff that supplemental oxygen should be reduced for these patients; saturations of 93–94% were actually scored as “too low”. This could prompt nursing staff to further increase supplemental oxygen which could harm these patients. The AltNEWS allocated EWS points according to whether patients were in or out of range and no patients were placed at risk of T2RF.
Conclusion The NEWS system makes no allowance for patients at risk of T2RF. This may lead to potentially dangerous use of oxygen in this substantial group of patients. We recommend that a target oxygen saturation range should be set for all hospital patients on admission and oxygen scores within EWS systems should be adjusted to alert clinicians to scores above and below the target range.