The adoption of an RRS was associated with a reduction of cardiac arrests and a trend toward reduced mortality. The data presented here add to the collection of studies demonstrating decreased cardiac arrest rates after the adoption of an RRS. The reduction in arrests was not observed immediately; rather, the findings were most prominent in the second year of the eTeam. The lack of clear outcome benefit in the first several months after the start of the RRS operation is consistent with the findings of others,5,6 and probably reflects the normal course of this intervention. The need for a longer run-in period may also help explain why a large Australian/New Zealand collaborative study was unable to demonstrate a reduction in cardiac arrests at an end point of 6 months.21
Despite a decrease in cardiac arrests after the eTeam was initiated, the fraction of arrest victims exhibiting one of the calling criteria before arrest remained essentially unchanged. The latter, along with the fact that approximately two-thirds of calls required transfer to either the ICU or IICU, as opposed to the 20%–45% range documented in most other studies,22 – 26 suggests that the system was not used to its fullest potential, and that additional patient benefit could be realized with additional use.27 The reasons for what we perceive as underutilization are unclear but, from periodic review of cases, the reasons seem to include physician reluctance to accept help, refresher training of nursing and ancillary staff is too infrequent, and poor prior experiences with team members.
The diurnal variation in call volume has been observed in other studies of RRSs and has been interpreted as a sign of underutilization or poorer oversight of patients during the night.8,9 Staff behavior such as entry to rooms for medicine and meal distribution, physical therapy, patient education, and transfer of other patients probably represents a subtle form of monitoring that is not present at night, and that may contribute to greater daytime detection of events. Despite an increased presence of physicians and other staff during the day, a higher daytime call volume may also result from periods of resident unavailability or because response times are slow because of rounds, surgery, educational activities, or family meetings. Nights have also been associated with delays in defibrillation, and a lower overall survival from in-hospital cardiac arrest in an analysis of a large voluntary database.28 – 30 The frequency of acute cardiac neurologic and respiratory disease is subject to diurnal variation, with a greater severity recorded in late night to early morning.31 Together, these findings indicate a role for improved vigilance, monitoring, and perhaps change of practice during night hours. The data also suggest the possibility that the benefit of an RRS is based more on monitoring and event detection than the composition of the response team.
The points raised above, that staff behavior and training as well as level of monitoring may influence call frequency, is supported by the finding of a higher call volume in our IICU (Table 3). All patients in this unit have continuous electrocardiogram and oximetry; the unit has an open floor plan with a greater physician and nurse presence. Additionally, the IICU nurses respond to eTeam calls and are therefore likely to have the greatest understanding of the rationale, function, and benefits of the RRS.
Even with what we interpret to be incomplete use of the RRS, benefits were realized. Regression and time series analyses were used to assess the contribution of seasonal effects and other trends over the time studied; these analyses did reveal a natural decrease in mortality of both full-code and all-type mortality that questions the overall impact of the RRS on mortality. We also considered whether a change in patient characteristics could affect our results. Computation of monthly pooled comorbidity indices before and throughout the study period showed that our results were obtained at a time when the population of inpatients was actually becoming older, harboring a higher burden of chronic disease, and therefore likely to have a higher mortality. Diversion of patients toward palliative care was unlikely to have had a positive impact on hospital mortality, because the hospice unit mortality rate actually decreased during the study period. Likewise, it is reasonable to consider whether the movement of unstable patients from the ward to the ICU shifted the arrest and mortality burden to the latter location.28 We could not identify any trend in the data to support the latter possibility, although future consideration of this question with better tracking of ICU codes is certainly warranted. Other quality-improvement measures such as the introduction of a hospitalist service, enhanced infection control practices, a ventilator-associated pneumonia prevention program, and improvements in glycemic control may have influenced the results obtained; however, all such interventions were in place for at least 10 months before the start of the eTeam.
The eTeam is a largely social intervention with multiple components whose individual contributions to patient safety and survival are not known.32 It has been encouraged to think of medical emergency teams such as ours as being part of a larger RRS that includes 4 components: (1) an afferent arm, consisting of establishment of calling criteria, education, and support systems that lead to identification of patients in need; (2) an efferent arm consisting of the emergency team and its activities; (3) administrative and governance functions; and (4) data collection and quality-improvement activities.33 Although the most visible component of the eTeam and other RRSs may be the team and its activities, current data have failed to link either success or failure to team design per se. The rate-limiting step in team involvement is its activation by the ward staff (the afferent arm), where timeliness of activation has been associated with a lower mortality for some conditions.34 Establishing the afferent arm as part of a larger system involves the deliberate education of clinicians on the nature of critical illness, the need for early intervention, and also the establishment of criteria for summoning help. The presence of the latter has, in our experience, “given permission” to ward staff to call for help with patients for whom there has been suspicion of clinical decline, but there is some ambiguity as to the true problem. Likewise, knowing that an ICU outreach team will be called or that event rates are being scrutinized, may have provided either subconscious (Hawthorne effect) or conscious motivation for ward physicians to respond in a timelier manner to calls for evaluation or assistance. One can thus envision that an increase in ward nurse and staff awareness of clinical deterioration and earlier calling of both eTeam and non-eTeam physicians may be a strong contributor to the benefits of the RRS seen here and elsewhere.
If the overall benefit of the eTeam is the system per se, rather than the team, one may question the more costly diagnostic resources used by our team, and the more advanced level of training embodied by our team and others.6,35 An understanding that intensive care began too late in many cases, combined with sporadic lack of ICU bed availability, drove us to adopt a higher level of capability that allows many aspects of intensive care, such as point-of-care blood analysis, invasive line placement, continuous display of invasive and noninvasive waveforms, medication administration, and respiratory support, to begin before arrival in the ICU.
Because some departments expressed a fear that the eTeam would deprive their trainees of valuable educational experiences, our team design embraced an educational mission, a mission based on having the most experienced personnel available present during patient care. The presence of senior ICU personnel during the day has allowed some instruction to accompany bedside care during team involvement. The presence of point-of-care blood analysis and continuous monitoring enhances the educational and safety functions of the team by providing mentorship in the use and interpretation of diagnostic studies in an acute setting.
Criticism of prior work on RRS outcomes includes a reliance on subjective outcomes, failure to report cointerventions and staffing models, poorly defined criteria for cardiac arrest calls, and underreporting of mortality postintervention by excluding patients who were made DRN/no further resuscitation by the team.15 We attempted to present all variables that may have affected the results. Cardiac arrest events were classified as such in conformance with accepted standards, and consistent criteria were used to define these events through all periods studied.36 Whole-hospital mortality included all patients in a palliative mode of care on the regular wards, but did not include those formally discharged from the regular wards and readmitted to the hospice ward. In the times studied, there was a decrease in the number of patients who died on the hospice ward, so the trend toward improved mortality could not be easily explained by more frequent diversion of patients to the palliative care service. One limitation of this study is that we were not able to identify a contemporaneous control group for which we had comparable data. The VA uses an electronic medical record and, although we can observe patients in other VA hospitals (e.g., the San Francisco VA), we did not have access to outcome data that we used in this analysis.
In conclusion, an RRS, featuring a physician-led, high-capability medical emergency team, was successfully introduced and sustained in a hospital within the US VA Health Care System. A significant reduction in the rate of cardiac arrest was realized with this intervention, as well as a trend toward lower mortality. Our results suggest that further reductions in morbidity can be realized by use of RRSs throughout the VA network. Larger cooperative studies within the VA system are needed to more definitively assess impacts on mortality. Furthermore, comparison of different team designs among VA centers implementing RRSs may help define certain elements or characteristics of the system that contribute to better acceptance or better outcomes.
GKL helped with study design, conduct of the study, data analysis, and manuscript preparation; LMP helped with statistical analysis; LR helped with data collection and analysis; and THW helped with statistical analysis. All authors attest to the validity and accuracy of the data in this study and approved the final manuscript.
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