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Abstract
The National Early Warning Score (NEWS) system is in use throughout NHS Acute Trusts. It reliably picks up the small proportion of patients at high risk of death during their admission. However, during Acute Exacerbation of Chronic Obstructive Pulmonary Disease (AECOPD), where target saturations are 88–92% in selected patients, a high proportion of patients have NEWS ‘alerts’ when their oxygen levels are within the target range set by their clinician. This results in referral for urgent review by medical staff and/or an inappropriate increase of inspired oxygen which could exacerbate hypercapnic respiratory failure.
We therefore propose a simple modification to the NEWS system in patients at risk of hypercapnic respiratory failure. Three points are added for target saturations of 85% or less and two points are added for target saturations of 86–87%. For target saturations of 88–92%, no additional points will be added. This modification would be at the senior clinicians’ discretion.
We reviewed the observations of 1119 patients admitted with a primary diagnosis of AECOPD and compared them to 15,953 patients aged over 50 admitted to one of two acute medical units. Admission saturations were reviewed and compared with in-patient mortality.
Use of the current NEWS system resulted in 40% of patients with AECOPD scoring 2–3 points on their saturation alone despite most being in the saturation range recommended by the BTS1. In addition, their risk of mortality was significantly lower than patients without COPD in the same saturation range (See table 1). Our proposed modified NEWS system results in an improved ability to identify the patients at higher risk of mortality, thereby resulting in more efficient utilisation of medical resources and the reduction of inappropriate use of oxygen and risk of hypercapnic respiratory failure.
We have shown that the current NEWS system leads to a significant number of patients with AECOPD alerting when they have nationally recommended target oxygen saturations. A simple adjustment of the alerting threshold in this cohort could improve the system. This could also be applicable to other respiratory patients with or at risk of hypercapnic respiratory failure. 1. BTS guideline for emergency oxygen use.
