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Rapid Response Systems: how to interpret levels of evidence

Marcello Difonzo



BACKGROUND AND AIM: The Rapid Response System (RRS) has been introduced to prevent cardiac arrest, unplanned admissions to the intensive care unit, and death in hospitalized patients. Despite the constant and widespread presence of this system in worldwide hospitals, it remains debated whether its use improves patient outcomes. The aim of this narrative review is to describe the available evidence supporting the effectiveness of RRSs and to discuss the controversies on the lack of level 1 evidence studies.

METHODS: The literature search covers the period from 1 January 2000 to 31 March 2016.

RESULTS: Studies with different research designs, observational, quasi-experimental with non-randomized control group and experimental, and aggregate data of meta-analyses indicate a statistically significant reduction of in-hospital cardiac arrests and hospital mortality associated with the deployment of RRSs.

CONCLUSIONS: A RRS is a complex intervention in a complex system, such as a hospital. This complexity does not allow considering experimental trials only as the most appropriate methodology to answer at research objectives. Furthermore, the benefits of a RRS depend greatly on its proper use. Accumulating evidence suggests the importance to investigate barriers and facilitators that can affect the integration, within a hospital, of this complex intervention.


Rapid Response Systems; In-hospital Cardiac Arrests; Hospital Mortality; Levels Of Evidence; Complex Interventions

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