Medical emergency team activation: performance of conventional dichotomised criteria versus national early warning score

Abstract

Background: To activate the hospital's medical emergency team (MET), either conventional dichotomised activation criteria or an early warning scoring system may be used. The relative performance of these different activation patterns to discriminate high risk patients in a heterogenic general ward population after adjustment for multiple confounding factors has not been evaluated. We aimed to evaluate the dichotomised activation criteria used at our institution and the recently published national early warning score (NEWS, United Kingdom).

Materials and methods: Prospective point prevalence study at a university hospital in Finland. On two separate days, the vital signs of all adult patients without treatment limitations were measured. Data on cumulative comorbidity (Charlson comorbidity index), age, gender, admission characteristics and subsequent mortality were collected. Univariate and multivariate logistic regression models were used for unadjusted and adjusted performance testing.

Results: The cohort consisted of 615 patients. The dichotomised activation criteria were not associated with in-hospital serious adverse events (odds ratio 1.87, 95% confidence interval 0.55-6.30) or 30-day mortality (2.13, 0.79-5.72) after adjustments. For a NEWS of seven or more (the suggested trigger level for immediate MET activation), the adjusted odds ratios for the above mentioned outcomes were 7.45 (2.39-23.3) and 11.4 (4.40-29.6), respectively. Unlike the dichotomised activation criteria, NEWS was also independently associated with a higher 60- and 180-day mortality after adjustments.

Conclusions: NEWS discriminates high risk patients in a heterogenic general ward population independently of multiple confounding factors. The conventional dichotomised activation criteria were not able to detect high risk patients.