<p><strong>OBJECTIVES: </strong>Standard metrics for evaluating rapid response systems (RRSs) include cardiac and respiratory arrest rates. These events are rare in children; therefore, years of data are needed to evaluate the impact of RRSs with sufficient statistical power. We aimed to develop a valid, pragmatic measure for evaluating and optimizing RRSs over shorter periods of time.</p>

<p><strong>METHODS: </strong>We reviewed 724 medical emergency team and 56 code-blue team activations in a children's hospital between February 2010 and February 2011. We defined events resulting in ICU transfer and noninvasive ventilation, intubation, or vasopressor infusion within 12 hours as "critical deterioration." By using in-hospital mortality as the gold standard, we evaluated the test characteristics and validity of this proximate outcome metric compared with a national benchmark for cardiac and respiratory arrest rates, the Child Health Corporation of America Codes Outside the ICU Whole System Measure.</p>

<p><strong>RESULTS: </strong>Critical deterioration (1.52 per 1000 non-ICU patient-days) was more than eightfold more common than the Child Health Corporation of America measure of cardiac and respiratory arrests (0.18 per 1000 non-ICU patient-days) and was associated with &gt;13-fold increased risk of in-hospital death. The critical deterioration metric demonstrated both criterion and construct validity.</p>

<p><strong>CONCLUSIONS: </strong>The critical deterioration rate is a valid, pragmatic proximate outcome associated with in-hospital mortality. It has great potential for complementing existing patient safety measures for evaluating RRS performance.</p>

<p><strong>BACKGROUND: </strong>Rapid response systems (RRSs) aim to identify and rescue hospitalized patients whose condition is deteriorating before respiratory or cardiac arrest occurs. Previous studies of RRS implementation have shown variable effectiveness, which may be attributable in part to barriers preventing staff from activating the system.</p>

<p><strong>OBJECTIVE: </strong>To proactively identify barriers to calling for urgent assistance that exist despite recent implementation of a comprehensive RRS in a children's hospital.</p>

<p><strong>METHODS: </strong>Qualitative study using open-ended, semistructured interviews of 27 nurses and 30 physicians caring for patients in general medical and surgical care areas.</p>

<p><strong>RESULTS: </strong>The following themes emerged: (1) Self-efficacy in recognizing deteriorating conditions and activating the medical emergency team (MET) were considered strong determinants of whether care would be appropriately escalated for children in a deteriorating condition. (2) Intraprofessional and interprofessional hierarchies were sometimes challenging to navigate and led to delays in care for patients whose condition was deteriorating. (3) Expectations of adverse interpersonal or clinical outcomes from MET activations and intensive care unit transfers could strongly shape escalation-of-care behavior (eg, reluctance among subspecialty attending physicians to transfer patients to the intensive care unit for fear of inappropriate management).</p>

<p><strong>CONCLUSIONS: </strong>The results of this study provide an in-depth description of the barriers that may limit RRS effectiveness. By recognizing and addressing these barriers, hospital leaders may be able to improve the RRS safety culture and thus enhance the impact of the RRS on rates of cardiac arrest, respiratory arrest, and mortality outside the intensive care unit.</p>

<p><strong>BACKGROUND: </strong>Early warning scores (EWSs) assign points to clinical observations and generate scores to help clinicians identify deteriorating patients. Despite marginal predictive accuracy in retrospective datasets and a paucity of studies prospectively evaluating their clinical effectiveness, pediatric EWSs are commonly used.</p>

<p><strong>OBJECTIVE: </strong>To identify mechanisms beyond their statistical ability to predict deterioration by which physicians and nurses use EWSs to support their decision making.</p>

<p><strong>DESIGN: </strong>Qualitative study.</p>

<p><strong>SETTING: </strong>A children's hospital with a rapid response system.</p>

<p><strong>PARTICIPANTS: </strong>Physicians and nurses who recently cared for patients with false-positive and false-negative EWSs (score failures).</p>

<p><strong>INTERVENTION: </strong>Semistructured interviews.</p>

<p><strong>MEASUREMENTS: </strong>Themes identified through grounded theory analysis.</p>

<p><strong>RESULTS: </strong>Four themes emerged among the 57 subjects interviewed: (1) The EWS facilitates safety by alerting physicians and nurses to concerning changes and prompting them to think critically about deterioration. (2) The EWS provides less-experienced nurses with vital sign reference ranges. (3) The EWS serves as evidence that empowers nurses to overcome barriers to escalating care. (4) In stable patients, those with baseline abnormal physiology, and those experiencing neurologic deterioration, the EWS may not be helpful.</p>

<p><strong>CONCLUSIONS: </strong>Although pediatric EWSs have marginal performance when applied to datasets, clinicians who recently experienced score failures still considered them valuable to identify deterioration and transcend hierarchical barriers. Combining an EWS with a clinician's judgment may result in a system better equipped to respond to deterioration than retrospective data analyses alone would suggest. Future research should seek to evaluate the clinical effectiveness of EWSs in real-world settings.</p>