Modified Early Warning Score (MEWS)

The scoring system explained

The Modified Early Warning Score identifies patients at risk of adverse outcomes and who are likely to require specialized levels of care, possibly with admission to an intensive care unit or high dependency unit.

MEWS is based on the principle that clinical deterioration can be forecasted through subtle changes in a number of patient parameters thus it is based on four standard physiological parameters that are usually monitored at the patient bedside and on a consciousness assessment (AVPU).

Systolic blood pressure offers information about the blood circulation whilst heart rate checks the pump function of the heart and indirectly the integrity of the coronary veins.

Respiratory rate offers information on the pulmonary function (the inhalation and expiration processes). Body temperature is indirectly used to check for signs of infection.

AVPU is used as a level of consciousness test and evaluates the patient’s awareness to surroundings and reaction to voice and pain stimulation.

In the table below you can find the answer choices provided in the score (and their awarded number of points):

MEWS can be used in the screening of patients whose condition is rapidly declining, in order to check whether transfer to a higher degree of care is required. It is not limited to use just in admission, like other scores may be (i.e. Glasgow coma scale).

The assessment can be administered by any medical specialist with very little training (in respect to scoring method).

There are several versions of the score available, as it has been calibrated in time to respond to different populations and in some cases, new parameters have been added.

The Royal College of Physicians in the UK has developed a similar model, the National Early Warning Score (NEWS) and there is also a pediatric version, the Pediatric Early Warning Score (PEWS).

Result interpretation

The five criteria are awarded each a number of points, varying from 0 to 3, depending on the severity of the parameter and the involvement in determining an adverse outcome. The final result sums these points and ranges from 0 to 14.

The guideline from the study is that scores ≥5 are statistically linked to increased likelihood of death or admission to an intensive care unit or high dependency unit. If the patient scores 3 in a component, regardless of the overall result, the patient is likely to require a higher level of care.

The following table introduces the three score categories and their indication:

About the study

The Modified Early Warning Score was created in 2001 by Subbe et al. based on the Early Warning Score (originally described by Morgan et al. in 1997) with the aim to identify medical patients at risk of catastrophic deterioration.

Data on 709 cases was analysed with the main outcome measure being:

■ Death;

■ Intensive care unit (ICU) admission;

■ High dependency unit (HDU) admission;

■ Cardiac arrest;

■ Survival;

■ Hospital discharge at 60 days.

The modified score was found to accurately identify patients at risk of serious adverse outcomes and who need increased levels of care.

Scores of 5 or more were found to be associated with the following:

■ Increased risk of death (OR 5.4, 95%CI 2.8-10.7);

■ ICU admission (OR 10.9, 95%CI 2.2-55.6);

■ HDU admission (OR 3.3, 95%CI 1.2-9.2).

Original source

Subbe CP, Kruger M, Rutherford P, Gemmel L. Validation of a modified Early Warning Score in medical admissions. QJM. 2001; 94(10):521-6.

Other references

1. Gardner-Thorpe J, Love N, Wrightson J, Walsh S, Keeling N. The Value of Modified Early Warning Score (MEWS) in Surgical In-Patients: A Prospective Observational Study. Ann R Coll Surg Engl. 2006; 88(6): 571–575.

2. Suppiah A, Malde D, Arab T, Hamed M, Allgar V, Morris-Stiff G, Smith A. The Modified Early Warning Score (MEWS): an instant physiological prognostic indicator of poor outcome in acute pancreatitis. JOP. 2014; 15(6):569-76.

3. Alam N, Hobbelink EL, van Tienhoven AJ, van de Ven PM, Jansma EP, Nanayakkara PW. The impact of the use of the Early Warning Score (EWS) on patient outcomes: a systematic review. Resuscitation. 2014; 85(5):587-94.

4. Morgan RJM, Williams F, Wright MM. An early warning scoring system for detecting developing critical illness. Clin Intensive Care 1997; 8: 100