Early warning scores (EWSs) are forms of track-and-trigger scoring systems that have been used in acute healthcare settings for many years. A report published in 2007 raised concerns regarding the lack of standardisation of EWSs across the NHS (National Confidential Enquiry into Patient Outcome and Death (NCEPOD), 2007). This led to the development of the National Early Warning System (NEWS) (Royal College of Physicians (RCP), 2012).
NEWS is a standardised tool that can be interpreted consistently by clinicians. Its use was recommended in acute settings across the NHS. NEWS uses six physiological measurements: respiratory rate, oxygen saturation, temperature, systolic blood pressure, heart rate and level of consciousness. Each scores 0–3, and individual scores are added together for an overall score. An additional 2 points are added if the patient is receiving oxygen therapy. The total possible score ranges from 0 to 20. The higher the score, the greater is the clinical risk for the patient. Higher scores indicate the need for escalation, medical review and possible clinical intervention, as well as more intensive monitoring (RCP, 2012).
EWS systems were originally developed to facilitate timely recognition of patients with established or impending critical illness and to empower nurses and junior medical staff to obtain experienced help through the operation of a trigger threshold, which, if reached, required mandatory attendance by a more senior member of staff. Escalation triggers are scores of 3 in any parameter and scores that total 5 and 7, which trigger a clinical review. A score of 7 or more triggers a critical care referral (RCP, 2012). Box 1 outlines the advantages of a NEWS score.
A review of 33 EWSs found that NEWS was the most effective in identifying patients at risk of cardiac arrest, unanticipated intensive care unit admission or death within 24 hours (Smith et al, 2008). NEWS is effective in these cases, because as mentioned by McGinlay and Pearse (2012), ‘patients die not from their disease but from the disordered physiology caused by the disease’. A NEWS score of ≥5 has been found to be effective in identifying cases of possible sepsis (RCP, 2012).
A survey carried out in 2017 showed that NEWS had not been adopted consistently in acute hospitals: 65% of hospitals were using NEWS, 14% were using an adapted form of NEWS and 20% were using another EWS (NHS Improvement, 2017).
The revised National Early Warning Score
In 2017, a revised form of NEWS (NEWS2) was released (RCP, 2017). This system measured the same six physiological measures as NEWS (respiratory rate, oxygen saturation, temperature, systolic blood pressure, heart rate and level of consciousness), but the recording of these physiological parameters was reordered to align with the Resuscitation Council (UK) ABCDE sequence (Nolan and Soar, 2015). The NEWS2 chart has a new colour scheme, reflecting the fact that the original red– amber–green colours were not ideal for staff with red/ green colour blindness. The section of the chart for recording the rate of oxygen and the device used has been improved. The section measuring level of consciousness has a new aspect added, namely, ‘new confusion’ (which includes disorientation, delirium or any new alteration to mentation), to the Alert Verbal Painful Unresponsiveness (AVPU) score, becoming ‘ACVPU’ (where C represents confusion). The importance of considering serious sepsis in patients with known or suspected infection, or at risk of infection, is emphasised. A NEWS2 score of 5 or more is the key trigger threshold for urgent clinical review and action. Box 2 outlines how NEWS2 differs from NEWS.
One of the shortcomings of the original NEWS was that people with chronic respiratory diseases, such as chronic obstructive pulmonary disease (COPD), consistently had high scores due to low oxygen saturation, elevated respiratory rates and, in some cases, the use of supplementary oxygen. NEWS2 has two oxygen saturation scales. Scale 1 should normally be used on all patients. Patients who have a confirmed diagnosis of hypercapnic respiratory failure on blood gas analysis (usually because of COPD) should be assessed using scale 2. The decision to use scale 2 must be made by a suitably qualified clinician, normally, a physician, and the medical notes should clearly reflect this decision.
If paper charts are used, the clinician making the decision about which oxygen scale to use should cross through the scale that is not in use, sign next to this amendment and ensure the medical notes clearly reflect the decision.
NEWS2 in community settings
In 2018, NHS Improvement and the RCP issued a patient safety alert that required all acute NHS hospital trusts and ambulance trusts to introduce NEWS2 by March 2019 (NHS Improvement and RCP, 2018).
Now, when community nurses call 999 requesting an ambulance to take a person to hospital, they are asked to provide a NEWS score. They report that when the NEWS score is high, ambulance staff prioritise the call.
NEWS2 has been advocated for use in pre-hospital settings in the UK, such as general practice, mental health services, and ambulance services (RCP, 2012; 2017; NCEPOD, 2017).
EWSs such as NEWS were developed on the basis of observations from hospitalised patients. Multiple NEWS recordings are taken over time, and this allows clinicians to track progress or deterioration. There is a lack of evidence of the effectiveness of EWSs outside of hospitals (Fullerton et al, 2012; Roland and Jahn, 2012; NHS England, 2019).
A large systematic review of 17 studies (involving 157 878 participants, 16 ambulance services and one nursing home) on predictive accuracy found that, although very low and very high scores were predictive of deterioration, the outcomes for those with an intermediate score (4–5) were unclear (Patel et al, 2018). The authors stated that EWSs should be used as an adjunct to clinical decision-making rather than as a substitute for it, and they recommended further research (Patel et al, 2018).
In 2015, NEWS was introduced in all healthcare settings in the west of England. It was used for prompt recognition of severe illness and to support escalation from the community into acute care. The thresholds were, as in acute care, a score of 3 in one parameter or a total of 5 (for review) or 7 (onward referral). Scott et al (2019) examined data from 115 030 emergency department (ED) attendances, 1 137 734 ambulance electronic records, 31 063 community attendances and 15 160 GP referrals into secondary care. They found that 8% of ED attendances, 18% of ambulance attendances, 11% of community attendances and 30% of GP referrals had NEWS scores of 5 or more. The authors concluded that high NEWS scores were reasonably uncommon. They stated that there was a need for further research to determine if the thresholds for action escalation used in hospitals were appropriate in community settings (Scott et al, 2019).
The limitations of NEWS2
NEWS2, like its predecessor NEWS, has its limitations and is not a comprehensive assessment tool. One of the greatest limitations of both NEWS and NEWS2 concerns blood pressure. The blood pressure parameter is not scored until systolic blood pressure reaches 220 mmhg, and diastolic blood pressure is not taken into consideration. Grant (2018) outlined the importance of identifying and responding to hypertension before it reaches these levels. It also pointed out the importance of diastolic blood pressure measurements in acute illness, such as anaphylaxis, sepsis and neurogenic shock.
The section measuring level of consciousness now includes the parameter ‘new confusion’ in the AVPU score, making it ACVPU. However, it can be difficult for clinicians who are assessing a person for the first time to determine if any confusion is new or chronic. People who have dementia, stroke, Parkinson's disease and other conditions may have chronic confusion. Ideally, the clinician would obtain collateral history from a relative or caregiver, but this might not be possible, and the person may be inappropriately escalated to A&E. Mohammed et al (2019) found that inclusion of delirium within the score led to a substantial increase in medium- and high-level alerts within hospital settings.
Pimentel et al (2019) compared the ability of NEWS and NEWS2 to identify patients at risk of in-hospital mortality and other adverse outcomes. Their multi-centre retrospective observational study at five acute hospitals from two UK NHS trusts assessed 251 266 adult admissions and found that 48 898 of these patients were at risk of type 2 respiratory failure (T2RF). They found that the modifications to NEWS do not improve discrimination of adverse outcomes in patients with documented T2RF and hamper identification of patients at risk of T2RF. They recommended further evaluation of the relationship between SpO2 values, oxygen therapy and risk before wide-scale adoption of NEWS2 (Pimentel et al, 2019).
Conclusion
At present, NEWS is the most effective EWS in use for predicting patients at risk of cardiac arrest, unanticipated intensive care unit admission or death within 24 hours (Smith et al, 2008). NEWS2 has not yet been subjected to rigorous evaluation in hospital settings (McGinley and Pearse, 2012; Mohammed et al, 2019; Pimentel et al, 2019; Scott et al, 2019), and there is a need for further studies to determine its effectiveness.
Evidence that it is appropriate to use NEWS2 in community settings is lacking. It is unclear if it is of use when assessing people who, because of long-term conditions, such as end-stage renal failure and end-stage heart failure, have abnormal physiological parameters and who have not been formally assessed as requiring palliative care.
If NEWS2 is appropriate in pre-hospital settings, are the escalation triggers used in hospital settings appropriate in the community? (Fullerton et al, 2012; Scott et al, 2019). It is important to determine when NEWS2 would be used in the community, who should review abnormal scores and how quickly these should be reviewed.
EWS scores were adopted in the NHS 10 years ago, and despite extensive training and auditing, NEWS observations are not always taken at the appropriate frequency or escalated appropriately. Further, when escalation does take place, medical staff do not always take appropriate action (Petersen et al, 2014). If NEWS2 is to be introduced in community settings, then it should be piloted and then phased in, so any lessons from the pilot can be used to inform implementation.
Although NHS England (2019) emphasised that NEWS2 is a supplement and not a substitute for clinical assessment, there is a danger that ambulance services and hospital doctors place undue emphasis on the NEWS score when discussing ambulance dispatch and hospital admission. This might lead to increased admission of older people with confusion, or to the urgent need for medical attention to be overlooked in those with a low score (Grant and Crimmons, 2018).
The adoption of NEWS2 by acute hospitals and ambulance trusts is leading to this scoring system being introduced in the community without the preparation that would be deemed essential if it were formally introduced. If NEWS2 is to be introduced in community settings, there should be a pilot phase with adequate staff training, support and changes to established systems. NEWS2 can potentially save lives and improve quality of life, but it is important to ensure that it does not lead to inappropriate triggering or late detection of illness. If it is not introduced in a considered and structured way, there is the risk that people will be inappropriately sent to hospital, pressure on the acute sector will increase and people who require lifesaving treatment will slip through the cracks.