Early Warning Score For Improved Patient Outcomes

By Paurakh Rajbhandary, senior biomedical engineer, VitalConnect.

Paurakh Rajbhandary

The need for hospitals and physicians to recognize and react to patients showing early signs and symptoms of clinical deterioration has resulted in the creation of a rapid response system (RRS). Patient deterioration prior to adverse events including cardiac arrest and ICU admission has been reported with hemodynamic antecedents in 60 percent of critical events. For example, patients who develop cardiopulmonary arrests exhibit clinical deterioration such as respiratory distress as early as eight hours in advance of arrest in 84 percent of the patients.

The RRS system, aimed at detecting precursors to and reducing such avoidable adverse events, comprises of track-and-trigger or afferent (detection) component for event detection, and efferent (response) component comprising of rapid response team (RRT) or medical emergency team for intervention and prevention of patient deterioration. Rapid response systems also comprises of administrative components and continual process improvement.

MET criteria is commonly used as an afferent triggering metric currently in many healthcare systems, but MET criteria is based on threshold of single vital or physiological measurement. The need of a good afferent component to RRS has been previously pointed out. Early warning score (EWS) combines multiple vital measurements to create a more comprehensive yet simple unified score that has been clinically validated to indicate increased risk of patient deterioration.

Among several different versions of early warning scores currently used in different healthcare settings, National Early Warning Score (NEWS) is standardized and endorsed by National Health Services (NHS) and Royal College of Physicians (RCP) in an effort to eliminate lack of consistency in the clinical workflow.

NEWS is an aggregate score calculated based on six physiological parameters: respiratory rate, oxygen saturations, temperature, systolic blood pressure, pulse rate, level of consciousness, and whether the patient is using supplemental oxygen. A sub-score within from zero to three is allocated to each of these parameters, giving an aggregated NEWS score between zero and 20 reflecting how patient status varies from the norm. The sub-score contribution criteria for each of the parameters has been determined and validated clinically by the NHS and Royal College of Physicians. The NEWS score dictates clinical urgency, the magnitude of response as well as frequency of clinical monitoring of the patient.

NEWS has demonstrated superior performance in determining patients at risk of cardiac arrest, unanticipated intensive care unit (ICU) admission or death within 24 hours of a NEWS value compared to 33 other early warning scores. Sensitivity and specificity performance of early warning scores dictates the trade off between alarm fatigue and ability to flag all deteriorating patients. Studies have shown that NEWS provides the best compromise between sensitivity and specificity allowing hospitals and healthcare providers to predict and reduce the aforementioned deterioration and improve patient outcome.

National Health Service (NHS) has been pushing to implement NEWS in all of its hospitals since its initial launch in 2012, having achieved implementation at 70 percent of acute trusts in England and with other forms of early warning scores in the remaining trusts. Variation in early warning scores systems can lead to confusion and potentially compromise performance of the detection of patient deterioration, patient safety and positive outcome. With this in mind, NHS are launching a campaign to increase NEWS use to 100 percent at acute and ambulance settings by March 2019.

NEWS is also recommended by NHS to be implemented in pre-hospital assessment of acutely ill patients by first responders, including ambulance services and primary care, to improve the communication of patient illness severity to receiving hospitals. NHS recommends NEWS should be used for initial assessment of acute illness and for continuous monitoring of a patient’s well-being throughout their stay in hospital. Recording NEWS periodically can provide information on the trend of patient status and provide a trigger for escalation of clinical care. It can also provide guidance about the patient’s recovery and return to stability thereby providing guidance on frequency of monitoring and on slowly triaging towards patient discharge. The effectiveness of NEWS is shown when the West of England Patient Safety Collaborative (PSC) started a three-year standardization program:

“In 2015, West of England patient safety collaborative started a three-year project to standardize use of NEWS across all acute trusts in the West of England AHSN region and to extend the use of NEWS scores into pre-hospital care. It used the Institute for Health Improvement’s breakthrough collaborative approach to influence change across a whole system. From 2014/15 to 2016/17 – the first two years of the project – “suspicion of sepsis” admissions in the West of England AHSN region rose from 61,000 to 69,000, and mortality rates dropped from by 13 percent. By October 2017, this region had the lowest mortality rate from suspicion of sepsis in England.”

Rapid response teams became more pervasively adopted in U.S. hospitals after the launch of the 100,000 Lives Campaign in 2004 by the Institute for Healthcare Improvement and the introduction of rapid response teams as one of six initiatives to improve the quality of patient care. Most rapid response team systems in the U.S. are triggered by change in one of the vital signs. For example, a significant change in blood pressure might trigger a call to the rapid response team, or a significant change in skin color might trigger a call. In response to IHI’s campaign, many hospitals have implemented rapid response teams/METs, but adoption of early warning scores is lagging and still catching up to the implementation of rapid response team/MET.

In 2006, with the initial goal exceeded, IHI introduced a ‘‘5 million lives” campaign again recommending rapid response team as a core component recognizing that “failure to rescue” events are a major cause of mortality in American hospitals. Agency for Healthcare Research and Quality (AHRQ) and American Hospital Association (AHA) also endorses rapid response teams and early warning score score adoption in the US hospital settings. Some examples of early adoption are:

NHS adoption of early warning score has shown it to be a good afferent component to rapid response team (RRT) in improving patient outcomes and making clinical workflows effective through early prediction of patient deterioration. While adoption has been slower in the U.S., early adopters are using EWS to trigger RRT with positive outcomes. Medical device vendors including Philips, Medtronic and VitalConnect are also integrating EWS systems into their platform to further help with adoption. The continued use of EWS will lead to a systematic approach to improve patient outcomes.

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