Are rapid response systems effective in reducing hospital mortality?

Cardiac arrest is the most serious of the in-hospital adverse events, carrying a mortality rate of around 80% at hospital discharge. Patients often show signs of physiologic deterioration in the hours before IHCA occurs and this has been the rationale for the introduction of rapid response systems (RRSs) in hospitals, with the aim of identifying and treating deteriorating patients in unmonitored hospital areas. Unfortunately, although many hospitals have implemented RRSs, a definitive evidence supporting their use is still lacking. In a meta-analysis of 18 studies, RRS reduced the rate of IHCA occurring outside the ICU, but did not lower overall hospital mortality. Furthermore, the only randomized multicenter trial on RRSs conducted so far did not demonstrate any benefit from the introduction of a RRS in a cluster of hospitals compared with control hospitals. That study, however, had important methodological limitations as insufficient power, a likely incomplete blinding of the control arm, and a suboptimal implementation in the treatment arm. A recent before-and-after study from Al-Qathani and coworkers demonstrated a significant reduction not only of the non-ICU cardiopulmonary arrests, but also of hospital mortality. Furthermore, both the ICU readmission rate and the post-ICU hospital mortality decreased significantly between the two study periods. The optimal implementation of the RRS, including a preceding hospital-wide education campaign directed to hospital staff, a 4-hour interval between consecutive patient evaluations in the wards, and a favourable nurse-to-patient ratio (1:4) may help explain those remarkable results