EARLY WARNING SCORES & MEDICAL EMERGENCY TEAMS

Early Warning Score (EWS) systems use patient's vital signs to identify those who are most unwell and then provide escalated care to try to prevent them deteriorating further. For the sickest patients, this response consists of a Medical Emergency Team (MET) which immediately brings senior doctors and nurses experienced in acute medicine to the bedside.

The need for EWS & MET arose from observations by Intensive Care specialists that patients admitted acutely to their unit from in-patient areas often had ward observations that documented their deterioration prior to them become markedly unwell. This deterioration had not been acted upon either because it was not recognised, not communicated to medical staff, or those who attended had insufficient expertise to initiate treatment to reverse this deterioration.

Medical Emergency Team activation sticker

From this work, and the observations of the ACADEMIA study published in Resuscitation in 2004, it became apparent that a system was needed to identify patients most at risk of deterioration so that an appropriate escalation of medical & nursing care could occur in a timely fashion. Such a system, based on deviation in physical observations from a normal set of values, was first described in the Quarterly Journal of Medicine in 2001. The further the observations were from normality then the higher the score allocated to them. A composite score (EWS) made up of the different parameters allowed a simple escalation pathway to be followed, with sicker patients having higher scores.

Hospitals allocated system resources to the end-point of continued deterioration (the training and availability of Cardiac Arrest teams), but little was in place to recognise early events that may precede this. This suspicion was confirmed in a paper by Schein et al published in Chest in 1990 which observed that of 64 patients who had arrested within 160 hours of hospital admission, 84% of them had a documented clinical deterioration preceding this.

In June 2011, after 18 months of development, Wellington Regional Hospital introduced a new adult Early Warning Score (EWS) system to replace the previous Patient At Risk (PAR) scoring system.

The new EWS system now included mandatory Medical Emergency Team (MET) calling for patients whose observations indicated they were severely ill and in need of urgent medical attention.

A graded scoring system precedes this activation with mandatory steps designed to either increase observation frequency or reverse early deterioration by increasing treatment levels and bedside expertise.

The entire system was revised in 2015 and updated based on new evidence. This was implemented in September of that year and launched with the new Paediatric EWS system.

In its first year of use in Wellington Regional Hospital, the new EWS & accompanying vital sign chart reduced in-patient cardiac arrests by 30%

ADULT EWS MATRIX

ESCALATION PATHWAY

To coincide with the new scoring system and escalation pathway, the opportunity was taken to create a single adult vital signs chart to replace the large number of charts that existed in different clinical areas.

The fluid balance chart was also redesigned and united with the vital signs chart to create an A3 size colour-coded double-sided chart. This provided space for a complete set of vital signs on a single patient over a 48 hour period, along with EWS calculations and the escalation pathway (both shown above).

Front

Back

WELLINGTON ADULT VITAL SIGNS CHART
(click for larger versions)

Various forms of the chart were trialled in different clinical areas with nursing & medical staff observed recording vital signs and calculating EWS. The final version was rolled out to adult in-patient areas in June 2011 to both medical and surgical wards. Several alterations to the design were needed to cover specialist areas found in a large tertiary centre, namely Medical High Dependency, Cardiology, Cardiothoracic Surgery, and Neurosurgery.

The EWS was subsequently revised and the vital sign charts updated during 2015 with an organisation-wide rollout of the improved system in September.

Working parties from the Paediatric and Obstetric departments were set up to look into applying similar systems in their unique areas of practice. The latter developed a Wellington 'MEOWS' chart which was implemented late in 2012. The Paediatric department adapted the revised Wellington adult chart using parameters derived from Canterbury DHB's work. The age-specific charts can be found in the online EWS library.

All charts have been constructed in-house using Adobe InDesign with master copies preserved to allow further modifications with minimal effort.

A review of the EWS systems in all New Zealand District Health Boards (DHBs) has shown a large variance in the parameters and scores used. This conflicting approach to deteriorating patients within the same health system has led for some authors to call for a standardised New Zealand early warning score.

A joint approach to developing a national medication chart for in-patient use has resulted in all DHBs introducing the same document to minimise drug errors. A standardised vital sign chart using a national EWS and designed around ease-of-use, safety and with graphic design principles in mind may be the next logical step.

More information about such a proposal can be read by clicking on the nzEWS logo above.

Cardiac Arrest teams are the ambulance at the bottom of the cliff; Medical Emergency Teams are the fence at the top.

Please click HERE to watch a short video demonstrating how to use the old Wellington EWS chart
(requires QuickTime)

A free library of all the resources developed for Wellington's Early Warning Score & Medical Emergency Team systems can be accessed using the button to the right.

MET & EWS CHARTS

The designs are easily adaptable for other hospitals and, in consultation with the original authors, have been modified for use in Wairarapa DHB where they were successfully introduced in 2012. Following publication of the EWS library, other DHBs have also adapted the Wellington system for their hospitals.

In 2016, the Wellington system was chosen as the baseline for the New Zealand Health Quality & Safety Commission's national deteriorating patient program.

Following publication of our designs, several institutions in other countries (particularly in the UK & the US) have contacted us; they are currently modifying the Wellington charts for use in their hospitals.

A proposal for an electronic system to calculate the EWS & activate the appropriate system response was placed second in the New Zealand Health IT Clinician's Challenge in 2011.

More information on Medical Emergency Team activation in Wellington Hospital can be found here.

This page was last updated on Friday, 03 August 2018 16:14:44

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EARLY WARNING SCORES & MEDICAL EMERGENCY TEAMS