“Potential critical illness” refers to patients who do not have any obvious manifestation of organ failure on the surface, but without timely and effective intervention and treatment, their condition may rapidly deteriorate within a few hours or days, or even lose their lives  . Modified Early Warning Score (MEWS) was developed and improved by Subbe CP on the basis of EWS   . Studies have shown that MEWS can effectively help medical staff to identify patients with “potential critical illness” in an early, accurate and objective manner. It not only promotes the early implementation of relevant medical measures, but also reduces the death rate  (see Table 1). In 2001, the National Health Service (NHS) recommended it as one of the methods for the assessment and communication of medical staff in medical institutions, and recommended MEWS in the emergency department, Intensive Care Unit (ICU) and general departments. However, compared with the research on MEWS in emergency department and ICU, the application of MEWS in general departments lacks big data support, and the application effect is still being explored  . Therefore, the application of MEWS in general departments at home and abroad was reviewed, so as to provide a basis for the development of MEWS in general departments.
2. Application Background and Potential Analysis of MEWS in General Departments
2.1. Application Background of MEWS in General Departments
The application of MEWS in emergency department and ICU provides experience for general departments to develop MEWS  . Some studies have pointed out that among 254 emergency departments in UK, 87% of hospitals use MEWS to evaluate and predict patients’ conditions, and 93% of hospitals give recognition and support to this tool, and point out that MEWS can effectively predict whether emergency patients need to be admitted to general departments or transferred to ICU  . For ICU patients, effective condition assessment is the first step to save patients. The most authoritative and most widely used assessment scale is the Acute Physiology and Chronic Health Evaluation (APACHE II), which can predict the severity of patients with 90% accuracy. Some studies have pointed out that MEWS can also reach the same level, both of which have good clinical resolution  . Therefore, it is of practical significance to promote the application of MEWS in general departments based on its experience in emergency department and intensive care unit.
2.2. Advantage Analysis of MEWS Application in General Departments
2.2.1. MEWS Evaluation Indicators Are Easy to Be Collected and Calculated
MEWS includes body temperature, heart rate, respiration, systolic blood pressure and consciousness. The consciousness with A (Alert), V (Reacting to voice),
Table 1. Modified Early Warning Score (MEWS).
P (Reacting to pain), U (Unresponsive) score  . The other four indexes set several parameter intervals, and each parameter interval corresponds to a different score. During the evaluation, the corresponding parameter interval and score were determined according to the actual value of each index of the patient. Finally, the score values of the 5 items were added to obtain the total score. The higher the score is, the worse the patient’s current condition is. The score 0 - 4 is classified as mild disease, 5 - 8 as severe disease, and 9 as critical disease  . The vital signs of patients in general departments are the data that nurses must collect every day. MEWS can reflect the severity of this patient’s condition instantly by simple calculation, which is feasible without additional manpower and material resources. Dalton’s study also points out that nurses in general departments are willing to evaluate patients’ MEWS on time and report abnormal conditions to nurse practitioners or doctors, which indicates that the implementation of MEWS in general departments is feasible    .
2.2.2. Increase Effective Communication among Medical Staff
Patients with “potential critical illness” often show abnormal physiological indicators, such as: change in consciousness, abnormal blood pressure, shortness of breath, arrhythmia, decreased oxygen saturation (SpO2), or decreased urine volume, in a few hours or days before the condition changes, which are also known as “warning information”   . However, in the medical work, it is difficult for nurses to judge whether the positive signs of patients indicate serious changes from the overall perspective. There is often a delay in reporting a patient’s positive signs to a doctor or a failure to do so. Secondly, nurses tend to judge patients’ conditions based on clinical experience and intuition, resulting in “wrong judgment” or “omission” of patients’ conditions  , and then miss the best treatment time, leading to irreversible consequences. Combined with vital signs and consciousness, MEWS covers the respiratory, circulatory and nervous systems, and reflects the overall condition of the patient with the most simple and direct score. MEWS can help the other party to grasp the patient’s condition faster and more effectively  .
3. Application of MEWS in General Departments
3.1. Specific Departments Applicable to MEWS
In 2001, the National Health Service (NHS) recommended medical institutions and medical staff to use MEWS for disease assessment and communication  , and recommended the application of MEWS in emergency department, intensive care unit and general department    . In the report of Chubu Tokushukai hospital in Okinawa, Japan, MEWS was applied to all the general departments of the hospital. Clinical nurses evaluated MEWS for patients every day. When the total score reached 7, nurses and doctors conducted relevant treatment. The results confirmed that MEWS can effectively reduce the rate of cardiac arrest in inpatients  . There are few general departments applying MEWS in China, and most of them focus on the studies of single department   or single disease   , such as the use of MEWS in cardiology, and the application value of MEWS in cardiac arrest patients, etc. At present, the specific departments applicable to MEWS are still not clear. The literature was summarized in Table 2.
3.2. Dynamic MEWS Can Better Reflect Patients’ Conditions
Dynamic MEWS score can better reflect patients’ conditions in real time  . Nishjima once evaluated the MEWS once a day for all patients in the general department, the corresponding physiological indicators recorded into the nursing system, by the system automatically calculate the MEWS score, when reached 7 points, the system automatically alarm, ward nurses need to report the attending doctor, for the treatment of patients, during which continue to evaluate three times a day, if discover the patients need a higher level of medical care facilities, are immediately turned to ICU, unless the patient give up treatment agreement (Do Not Resuscitate, DNR)  . Most domestic studies have studied the degree of prediction of disease changes in patients with a certain static MEWS score, with the most related studies on single score at admission  . Su Yanhong evaluated 200 patients in the department of cardiothoracic surgery once a shift when they were admitted to the hospital and did not use ECG monitoring after surgery. When abnormal vital signs were found, it was necessary to report to the doctor at any time until the single score < 2 or the total score < 4, but the treatment process was not described in detail  .
3.3. Specific Application Process of MEWS
Penglingli applied MEWS in the general department of the hospital in 2014, and formed a relatively perfect application process: MEWS should be evaluated when patients are admitted to the hospital, returned to the ward after surgery, returned to the ward after surgery for 6 h, and transferred to the hospital. If single item > 2 or total score ≥ 4, the nurse should evaluate once per shift, and report the patient’s abnormal vital signs and the most urgent problems to the doctor in time until the score is reduced to normal. When the total score of MEWS is greater than 5, the nurse should increase the number of monitoring, follow the doctor’s advice for ECG monitoring if necessary, inform the superior doctor and  remind the “seriously ill” doctor’s advice; When the total score of MEWS is greater than 6, in addition to the above three points, it is also necessary to prepare for rescue, including opening the vein access, preparing rescue materials, and helping doctors contact ICU nurses  .
4. Limitations of MEWS Application in General Departments
MEWS Combined with Specialist Indicators Is More Accurate
The advantage of MEWS for general departments is that it is easy to evaluate projects. However, due to the changeability of patients’ conditions, the variety of diseases and the complexity between different departments, MEWS lacks accuracy
Table 2. Domestic and foreign studies on MEWS in single department or single disease.
and sensitivity in the evaluation of patients’ conditions   Delgado has changed the consciousness score from AVPU to GCS score on the basis of MEWS, and the results confirmed that the improved version of MEWS has good reliability and validity  . Ye explore BISAP, MEWS, Ca+, red blood cell width as Acute Pancreatitis, Acute Pancreatitis, AP) the influence of the factors, found that when used MEWS and other indicators that can effectively evaluate the occurrence of AP, but separate MEWS failed to predict the occurrence of AP  . Skaleaky M also established pediatric early warning score on the basis of EWS with specialized indicators, and determined that when the optimal cut-off point was 2.5, the maximum AUC of the score was 0.81, suggesting that it could help pediatric nurses to identify children with deteriorating conditions in the early stage  , indicating that MEWS combined with specialized indicators was more effective in general departments.
5. Effects of MEWS in General Departments
5.1. The Ability of MEWS to Predict the Prognosis of Patients in General Departments Remains to Be Explored
The ability of MEWS to determine the prognosis of patients in general departments remains to be explored   . Tirotta collected demographic data of 31 patients with continuous sepsis infection in the medical ward, the rate of transfer to the ICU, and MEWS, and found that MEWS had little risk value in predicting the in-hospital death of sepsis patients in the medical ward  . More systematic evaluation directly points out that: MEWS is not good at identifying and predicting the prognosis of patients with “potential critical illness” in general departments   . However, some studies suggest that MEWS is suitable for general departments. Lu xiaomin has analyzed the EWS score of 88 patients who were unplanned transferred to ICU in the surgical ward within 24 hours before the transfer, and found that EWS can identify patients with “potential critical illness” and help to determine the prognosis of patients  . Wenting Huang compared the NEWS, the BAP-65 scores, Chronic Respiratiory Early Score (CREW) three Score to predict the prognosis of patients with acute exacerbation of Chronic obstructive pulmonary disease period. It was found that the AUC of death predicted by NEWS was 0.878, and that of ICU admission was 0.826, indicating high performance  .
5.2. Poor Ability of MEWS in Identifying Patients with “Potential Critical Illness” in General Departments
Some studies have pointed out that although MEWS is recommended as an evaluation tool for many departments, it is not based on a large number of clinical studies, so its effectiveness cannot be guaranteed  , which is consistent with the views of many researchers in systematic evaluation    . Cooksley has retrospectively collected the MEWS scores of 840 patients in the oncology department to explore its ability to predict ICU transfer and death within 30 days, and found that MEWS has poor ability to identify cancer patients at risk of deterioration  . Therefore, in order to effectively promote MEWS at home and abroad, a large number of multi-center, large-sample and large-range clinical studies need to be improved  .
Patients with “potential critical illness” have high risk of irreversible negative events and poor prognosis. Early identification of patients with “potential critical illness” and early implementation of relevant intervention and nursing can effectively reduce the death rate and improve the prognosis of patients   . The main reason is that MEWS evaluation indicators are easy to collect and calculate. The simple score can reflect the overall condition of patients and facilitate communication between medical staff. However, due to the lack of unified application mode and application timing of MEWS, there are different opinions about the application effect of MEWS in general departments at home and abroad. According to the authors, the application of MEWS in general departments needs a unified application process, and only by adding specialist indicators and increasing the ability of MEWS to identify patients with “potential critical illness” can it be implemented in general departments.
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