Frequency of early warning score assessment and clinical deterioration in hospitalized patients: A randomized trial

Abstract

Aim: To explore whether early warning score (EWS) measurements at 8h intervals is associated with better outcomes than 12h intervals. We hypothesized that the proportion of patients that deteriorated to a higher EWS at 24h after hospital admission would be lower with 8h interval than with 12h interval.

Method: This was a pragmatic, ward-level randomized, non-blinded, controlled trial at an urban University hospital. During two six weeks periods acutely admitted surgical and medical patients, with an initial EWS of 0 or 1, were monitored either every 8th hour or every 12th hour. The primary outcome was clinical deterioration 24h post-admission, estimated by the proportion of patients with an EWS≥2 at 24h after the initial EWS on admission.

Results: Of 3185 patients screened for eligibility, 1346 patients were included to the trial. Forty-nine percent were allocated to the 8h group and 51% to the 12h group; of these, 23% and 20% had an elevated EWS≥2 at 24h, respectively (p=0.456), OR 1.17 (0.78-1.76); 3.4% and 2.2%, respectively had an EWS≥5 (p=0.391), and one patient in each group had an EWS≥7 at 24h (p=1.0). Multiple logistic regression analysis showed no significant interactions for the primary outcome and the predefined variables: age, gender, ward type, and inclusion period, with an adjusted OR 1.20 (0.79-1.82). There were no significant differences in regard to the secondary outcomes: cardiac arrests, ICU admissions, review by medical emergency team (MET), length of hospital stay, or elevated EWS at 48 h. Thirty-day mortality was 1.1% vs. 1.8% (p=0.357) in the 8h group and the 12h-group, respectively (OR=0.60 (0.23-1.50), p=0.279).

Conclusion: We found no significant reduction in the proportion of clinical deterioration with monitoring frequencies of 3 vs. 2 times daily among patients acutely admitted to a surgical or medical ward and an initial EWS of 0-1.

Keywords: Early warning score; Medical emergency system; On the ward deteriorating patient; Rapid response systems.