An intervention including the national early warning score improves patient monitoring practice and reduces mortality: A cluster randomized controlled trial.

Aims: To investigate the impact of the national early warning score on the frequency and the quality of vital sign registration and to study the association between protocol compliance and patient mortality.

Design: We conducted a post hoc data analysis of a stepped wedge cluster randomized controlled trial (RCT) in six hospitals.

Methods: All adult, non-pregnant patients admitted to 24 wards were included. The intervention comprised an observation protocol using the national early warning score combined with a pragmatic medical response strategy. Data collection lasted from October 2013-May 2015. Patient comorbidity scores and vital signs were sampled every 4 months on each ward. All vital signs in the 24 hr before a serious adverse event were collected.

Results: Patients (N = 60,956) were included of which 32,722 in the intervention group. Comorbidity scores were sampled in 3,600 patients and vital signs in 2,951 patients. In 668 patients, vital signs were collected before a serious adverse event. The mean number of vital signs per observation increased significantly in the intervention group. The observation frequency increased in patients with a serious adverse event and decreased in patients without a serious adverse event. Protocol compliance was negatively associated with patient mortality adjusted for comorbidity and age.

Conclusion: Our intervention improved patient monitoring practice and reduced mortality.

Impact: The impact of early warning scores on patient monitoring practice and patient outcomes remains unclear. Our intervention improved the observation of patients and reduced patient mortality. These results could support hospitals in their decision to implement rapid response systems.

Trial Registration: We have registered this study in the clinicaltrials.gov database (identifier: NCT01949025).