Commentary: is a change from the National Early Warning System (NEWS) warranted in patients with chronic respiratory conditions?

Early warning systems (EWS) were introduced in hospital systems in a number of countries including the UK (NEWS-1 and NEWS-2 UK) and Ireland (NEWS now INEWS V2) with the aim of identifying patients with acute physiological deterioration in a timely manner in order to prevent or reduce cardiopulmonary arrest, admission to the intensive care unit and premature death . Both NEWS-1 and NEWS-2 UK and INEWS are based on the ViEWS VitalPac EWS. However, INEWS uses precisely the same parameter ranges and scoring system as ViEWS while some minor modifications were made in NEWS-1 and NEWS-2 UK. These modifications included NEWS-2 UK introduced a second SpO2 scoring system for use in patients with hypercapnic respiratory failure who had a prescribed oxygen saturation requirement of 88 − 92%. The existing SpO2 scoring system (SpO2 scale 1) used in both NEWS-1 and NEWS-2 UK applies to the majority of patients. The new dedicated SpO2 scoring system (SpO2 scale 2) in NEWS-2 UK is used for patients with confirmed hypercapnic respiratory failure with the NEWS-2 UK scoring system adjusted accordingly. Previous reports have voiced concern that the SpO2 scoring system within the NEWS-1 UK and the Irish NEWS is not suitable for specific patient sub-populations, in particular those with chronic respiratory conditions including chronic obstructive pulmonary disorder (COPD). Some of these patients have a lived baseline of lower oxygen saturation levels, usually between 88 to 92% SpO2. An SpO2 below 95% triggers an alert within NEWS. This can result in excessive triggering and false alarms in this high risk sub-population of chronic respiratory patients as well as the potential for the inappropriate use of high levels of supplemental oxygen in hypercapnic patients. As part of the update to the Irish National Early Warning System (INEWS) National Clinical Guideline No.1 [see INEWS Guideline Version 2], the authors undertook a systematic review of the evidence comparing the NEWS-1 UK to modified EWSs (EWSs in which parameters are adjusted) in sub-populations of patients with chronic respiratory conditions including chronic hypoxia, chronic hypoxaemia, chronic physiological abnormalities, pulmonary fibrosis or COPD. The effectiveness of the modified EWSs in predicting mortality in this sub-population was compared to the NEWS-1 UK only.