Using the National Early Warning Score 2 with an adjusted target saturation among patients admitted to the hospital for COPD exacerbations reduces alert frequency without a notable difference in mortality when compared with unadjusted National Early Warning Score 2, a recent study suggests.
“Patients admitted with COPD exacerbations have a modest in-hospital mortality rate (3.9%-4.3%), but frequently trigger alerts on the National Early Warning Scale (NEWS),” the researchers wrote. “This can place a substantial burden on health care professionals, create complacency and promote excess oxygen use in those who are at particular risk of its harmful effects.”
Researchers examined 2,645 patients with COPD exacerbations admitted to one of six U.K. hospitals. All patients were required to meet spirometry criteria for COPD, and were analyzed with NEWS2, NEWS2 with adjusted target saturations to 88% to 92% for patients with hypercapnic respiratory failure and NEWS scores. Patients were also risk-stratified based on dyspnea, eosinopenia, consolidation, acidemia and atrial fibrillation (DECAF) scores. Alert appropriateness and frequency were measured for all NEWS assessments, with prognostic performance compared using the area under the receiver operating characteristic curve (AUROC).
Mean age of the patients was 73.1 years, with an average FEV1 of 45.1%. Overall inpatient mortality, the study’s primary outcome, was 8.6% — 10.4% in the DECAF derivation cohort and 7.7% in the DECAF validation cohort. The number of patients requiring urgent review, defined as a score of five or more, was 62.1% for adjusted NEWS2, 71.6% for NEWS2 and 74.7% for NEWS. Adjusted NEWS2 identified 9.5% fewer patients requiring medical review compared with NEWS2, but the risk for death among the low-risk group was similar (3.5% vs. 3.1%; P = .686).
With NEWS2, alert frequency was reduced from 71.6% to 68% for patients with a score of five or less if excess oxygen scores were discounted (P = .005). Additionally, discounting excess oxygen for adjusted NEWS2 reduced reviews from 62.1% to 58.6% (P = .01). Little difference was observed between deaths in the low-risk patient group for adjusted NEWS2 (3.5% with excess oxygen vs. 3.6% discounting excess oxygen; P = .905). Adjusted NEWS2 was also a stronger mortality predictor than NEWS (AUROC = 0.72; P <.001) and displayed a trend toward superiority with NEWS2 (AUROC = 0.72 vs. 0.7; P = .09).
DECAF was superior to all scores, with an AUROC of 0.82 in the validation cohort, for risk stratification. “Real-time recording of NEWS2 may result in changes in clinical behavior,” the researchers wrote. “Of concern, the NEWS2 implementation guidance and NEWS2 chart may result in many patients receiving excess oxygen prior to arterial blood gas analysis or clinician review. Randomized controlled trial data show a mortality benefit in those treated with oxygen target saturations 88%-92% at the point of ambulance pick-up.” – by Eamon Dreisbach
Disclosures: The authors report no relevant financial disclosures.