The relationship between early emergency team calls and serious adverse events*

Objective: To examine the relationship between early emergency team calls and the incidence of serious adverse events—cardiac arrests, deaths, and unplanned admissions to an intensive care unit—in a cluster randomized controlled trial of medical emergency team implementation (the MERIT study). Design: Post hoc analysis of data from cluster randomized controlled trial. Setting and Participants: Twenty-three public hospitals in Australia and 741,744 patients admitted during the conduct of the study. Interventions: Attendance by a rapid response system team or cardiac arrest team. Main Outcome Measures: The relationship between the proportion of rapid response system team calls that were early emergency team calls (defined as calls not associated with cardiac arrest or death) and the rate (events/1000 admissions) of the adverse events. Results: We analyzed 11,242 serious adverse events and 3700 emergency team calls. For every 10% of increase in the proportion of early emergency team calls there was a 2.0 reduction per 10,000 admissions in unexpected cardiac arrests (95% confidence interval CI −2.6 to −1.4), a 2.2 reduction in overall cardiac arrests (95% CI −2.9 to −1.6), and a 0.94 reduction in unexpected deaths (95% CI −1.4 to −0.5). We found no such relationship for unplanned intensive care unit admissions or for the aggregate of unexpected cardiac arrests, unplanned intensive care unit admissions, and unexpected deaths. Conclusions: As the proportion of early emergency team calls increases, the rate of cardiac arrests and unexpected deaths decreases. This inverse relationship provides support for the notion that early review of acutely ill ward patients by an emergency team is desirable.