It's not "do" but "why do" rapid response systems work?*.

www.ccmjournal. org 2133 Rapid response systems (RRS) are remaining controversial even as they become more common. In fact, some sort of RRS is now a patient safety goal promoted by the Joint Commission for Accreditation of Healthcare Organizations, this in spite of the academic and clinical debate. Originally reported in the mid 1990s (1), articles reporting some aspect of the RRS have become quite common. The Joint Commission Journal of Patient Safety and Quality has devoted a monthly report on the topic for several years, and just recently Resuscitation issued a call for articles on the topic because RRSs are seen as integral to a safe hospital (2). Yet data on RRS remain difficult to interpret. There are several reasons for this. First and foremost is the fact that the intervention is not a medicine, or a procedure, or even a discrete process. It is a complex system of care requiring largescale interaction of hospital personnel to detect deterioration, recognize it as a problem, trigger a response, and staff (and supply) a capable responder corps. Any step that is underperforming may render the whole operation useless. For example, the most brilliant response team will have no patient contact without being triggered to respond. Likewise, even if every opportunity to rescue a patient were identified, it would do no good unless the response is effective. A good system requires time to develop, focuses education for both the “detectors” and the “responders,” and has a culture change that promotes “others” helping in a crisis situation. A second problem with demonstrating benefit is that the optimal activation rate is not known, nor is it known whether all hospitals or units should aspire to a specific rate. “Dose” seems to matter: too low a RRS activation rate may be associated with no effect. Chen et al (3) demonstrated that the greater the number of calls, the greater the impact, at least as shown in a post hoc analysis of the Medical Emergency Response Improvement Team study (4) data (which in a cohort controlled primary analysis showed no benefit). Thus, if the “dose” is not right, no benefit should be expected. But what is the dose? A third problem with studying the intervention is the fact that some patients in hospital will die irrespective of their treatment (or intervention by the RRS). Those patients will confound the results if total mortality is the primary endpoint (as it most often is in studies examining RRS). Other measures like “unexpected” mortality are difficult to define. Other endpoints are confounded as well: ICU admissions is impacted by time of day, perceived quality of staff or monitoring outside the ICU, ICU bed availability, individual clinicians’ practice, and local culture. Finally, in doing a prospective randomized trial of a system of care, blinding is not possible because the intervention is a set of behaviors and not a medication: they will be observed. Furthermore, because the intervention is the behaviors, it is highly likely that cross contamination will occur as caregivers move within or between hospitals and individuals implement some workarounds which may mimic, or avoid, the RRS. RRSs are in fact so ubiquitous at this point that finding sites to adequately randomized would be nearly impossible and likely subject to significant bias. It sounds gloomy in terms of resolving the debate. Into this environment, in this issue of Critical Care Medicine, Salvatierra et al (5) report a very large, albeit observational study of the impact of RRSs on hospital mortality in the state of Washington. Using a database of almost half a million adult patients admitted to 10 of 16 tertiary hospitals in the state over nearly 9 years, they evaluated patient data from the Washington State Comprehensive Hospital Abstract Reporting System. They observed the mortality rate for 31 months prior to and following implementation of a RRS. Importantly, they controlled for a number of factors including time, patient severity of illness, and other complexities of patient care. All the hospitals had a triggering system that enabled virtually anyone to activate the system, and most had a small team with only an ICU nurse and respiratory therapist as responders. The major findings were a significant improvement in mortality with a risk reduction of 24% after implementation. Only six of 10 hospitals exhibited a statistically significant improvement. The remaining four had nonsignificant outcome impact. Examining why there were some hospitals with benefit and others without is the crux of the study. The six successful hospitals included two process changes in common: 1) Copyright © 2014 by the Society of Critical Care Medicine and Lippincott Williams & Wilkins DOI: 10.1097/CCM.0000000000000421 *See also p. 2001.