The early identification of patients with severe sepsis is a key point to provide the correct treatment and is actually based on clinical evaluation. In hospital wards, the Modified Early Warning Score has been proposed as a system to identify early signs of deterioration and for outreach team activation. However, MEWS sensibility in early recognition of septic patients is still unknown. The aim of this study was to evaluate whether MEWS ≥4 is an adequate threshold for early identification of patients with severe sepsis.
In 51 patients with severe sepsis (no septic shock) evaluated by our sepsis team, between November 2007 and December 2008 in the emergency department and no ICU wards, we collected the SOFA score and MEWS at the time of first evaluation, the ICU admission rate and the 30-day mortality rate. We subdivided and compared patients into two groups on the basis of a MEWS value ≥4.
In the 22 (43%) patients with a MEWS value ≥4, the SOFA score (5.9 ± 2.9) was similar to that measured in the 29 (57%) patients with MEWS value <4 (5.24 ± 2.6) whereas the ICU admission rate was larger (54%) than in patients with MEWS value <4 (24%) (P = 0.03). In patients with MEWS value ≥4 the 30-day mortality rate was slightly lower (15%) than in patients with MEWS value <4 (24%) (P > 0.05).
The above data indicate that a MEWS value ≥4 has a very low sensitivity (43%) for identification of patients with severe sepsis and therefore it should be used with caution for this aim and also as a criterion for ICU admission of septic patients (7/19 of patients admitted to the ICU with a MEWS value <4; sensitivity 63%, specificity 68%).