The Basic Principles of the EWS System - Essay Example

The Basic Principles of the EWS System One of the essential aspects of safe and effective patient care is the early identification of deterioration in a patient’s condition (Kause et al, 2004). This paper will focus on the effectiveness of early warning scores (EWS) in leading to the early recognition and treatment of clinical deterioration. The paper shall describe the basic principles of the EWS system, identify the recommendations regarding it that have been published in the literature, and discuss whether, and to what extent, the established policies on EWS are based on the latest evidence. The impact that these EWS systems have had on the early identification of the deteriorating patient will also be analysed, and conclusions regarding its effectiveness shall be made. The paper concludes with a summary of the key points discussed. It has been seen that clinical deterioration of patients in the hospital is often precluded by abnormalities in physiological parameters such as vital signs, and such deterioration subsequently leads to intensive care admissions. Failure by healthcare staff to respond to these changes early and carry out rapid interventions poses a high risk of serious complications, including cardio- respiratory arrest (Smith and Oakey, 2006). These adverse outcomes are preventable through early recognition (Subbe et al, 2001; Heaps et al, 2005). To prevent these complications and provide early management, the early warning score or ‘track and trigger’ system has been introduced. Morris and Davis (2010) report that the concept of an early warning scoring system was first introduced by McQuillan et al. (1998) and McGloin et al. (1999). The National Institute for Clinical Excellence (NICE) describes EWS as a tool that can help identify relatively stable patients outside the critical care unit – in general wards - that are likely to become unstable (NICE, 2007). EWS systems enable healthcare professionals to closely monitor changes in the patients’ physiological condition, categorize patients by the severity of clinical status, predict impending serious adverse events, and identify deterioration in clinical status. These tools promote improved communication within the multidisciplinary team. This allows corrective measures can be taken at the earliest (Windle & Williams, 2009). Hence, this approach can help in reducing avoidable mortality, morbidity, the duration of patient stay and, ultimately, preserving healthcare resources and minimizing healthcare- associated expenditures (NICE,2007; NPSA, 2007). The EWS systems are taken to be highly effective tools for ward-based nursing staff for the early identification of patients who are likely to deteriorate to critical level (Ryan, 2004), and implementation of T&T systems have also been recommended by NICE (2007) for this purpose. In 2000, the Department of Health introduced recommendations under the title “Comprehensive Critical Care” with the aim of improving the recognition and management of the deteriorating patient. The National Health Service (NHS) Trust was tasked with developing appropriate services to meet the need of critically ill patients (NICE, 2007). There are several issues regarding the management of patients who deteriorate in the hospital, which would be addressed by early warning scoring systems. Abnormalities in patients’ vital signs are often identified before they are assessed to be unstable and shifted to critical care. However, timely optimal care is not always provided to these patients, leading to many cases of cardiac arrest (Mckeown, 2004). Due to resource limitations, such as a limited number of beds in the high dependency units (HDUs) and intensive care units (ICUs) and the number of available ventilator machines, the number of patients that can be treated and monitored in these units is limited. For this reason, it is crucial to accurately identify those patients who would benefit most from critical care. This can be done if EWS systems are used. For a bedside evaluation, the Early Warning System uses five physiologic parameters: the pulse rate, respiratory rate, systolic blood pressure, temperature and neurological status (NICE, 2007). The Department of Health recommendations identified four stages of care in EWS: zero to three. Stage zero considers in-patients who are in stable condition in tertiary care health centers, who can be adequately cared for on the general inpatient floor. Stage one is designated for high-risk groups who are likely to develop acute complications requiring critical care, as well as those who have been shifted to the general management floor after stay in an ICU or HDU. Stage Two addresses in-patients that require aggressive monitoring – such as those with organ failure and those recovering from recent surgery. Stage Three is for patients requiring advanced ventilatory support or, simple breathing support along with management of at least two other body systems (NICE, 2007). The EWS system advises regular observations of patients’ physiologic parameters at 12-hourly intervals, unless a different checkup frequency is decided by senior healthcare providers (NICE, 2007). If any abnormal physiological changes are recognised, an increased frequently of monitoring is recommended. The appropriate health care staff to notify, and the urgency with which to send a report, upon observing an abnormality in the patient’s clinical status depends on the initial degree of severity of the patient’s condition (NICE, 2007). For example, for a patient initially in the low-score group, only more frequent monitoring, and alerting the head nurse, is necessary. For a patient in the medium-score group, any instability in vitals requires that an urgent call be issued to the primary care team. For patients in the high-score group, an emergency ‘rush’ call would be necessary, and the primary team as well as an emergency team of medical practitioners skilled in resuscitation, anaesthesia and advanced airway management would need to be summoned immediately (NICE, 2007). More complex scoring methodologies have also been studied by Subbe et al. (2001) and Garcea et al. (2006). Subbe et al. (2001) studied Modified EWS (MEWS). In MEWS, the parameters to be monitored include the vital signs (blood pressure, pulse, temperature, and respiratory rate), urine output and the neurologic status (ICS, 2002). It also includes an assessment of pain as well as biochemical analysis including the blood glucose level, serum lactate, and the base deficit (NICE, 2007). A change in the score indicates whether the patient is improving or deteriorating, and can thus trigger a response by the health care staff when the score falls to a dangerously low level. MEWS has been found to be adequately sensitive for this purpose (Symes and Thomas, 2010). Prytherch et al (2006) reports that ‘track and trigger’ systems more complicated than EWS and MEWS are prone to human errors, thus their reliability regarding the early identification of the deteriorating patient is lower. Thus, no other scoring system has been validated. ‘Track and trigger’ systems include guidelines on the immediate steps to take when clinical deterioration of a patient is suspected or recognized. The guidelines allow healthcare staff to recognise a trigger that requires summoning a more senior healthcare provider when a score is reached (Symes and Thomas, 2010). For example, a MEWS of 4 or more for a patient in the medium-score group triggers an immediate review for the patient’s condition (Thorpe, 2006). MEWS and EWS scores are also useful for stratifying patients by severity of illness, and predicting the patient’s prognosis. Subbe et al (2001) found that scores of 5 and above were associated with a higher mortality and ICU and HDU referrals. Garcea et al. (2006) found an EWS score of 3 or above to be associated with adverse clinical outcomes in acute pancreatitis patients. They concluded that EWS can be used reliably for selecting patients with severe acute pancreatitis that are at high risk of complications. In another study, 3 was identified as a trigger score for transferring the patient to advanced health care (Atkinson et al, 2004). Ball et al. (2003) demonstrated that EWS, when used along with outreach services, was associated with a reduced rate of cardiac arrest, reduced length of critical care patient stay, and reductions in mortality rate, number of readmission, and ultimately improved patients care. In addition, the use of EWS systems on general wards has been shown to increase the frequency of observations’ made by healthcare professionals (McBride, 2005). However, limitations in the EWS system exist, which need to be discussed. Not all studies on the EWS declare it to be reliable. Subbe et al. (2007) studied the Medical Emergency Team as a variable of EWS. They concluded that this variable is simple adequately accurate, however, it could not be used to monitor the patient’s condition. Gao et al. (2007) studied the effect of EWS on rates of death, critical care admissions and cardiopulmonary resuscitation. They found it to have a low sensitivity and concluded that the evidence to prove the reliability, validity and utility of EWS is minimal. As T&T systems involve observations (tracking) of the patients’ status at regular timed intervals, if the deterioration occurs at a point in time in between two tracking observations, a delay will be created until the next observation takes place, and thus, triggering of the response and notifying the appropriate health care staff about the patient’s deterioration may be delayed too far. Also, by the time that the observation takes place, the deterioration may have progressed to a point where the health care staff rushes the management and consequently makes errors and omissions. If the inappropriate health care staff is called due to an incorrect score calculation, this can also result in significant delays in providing timely adequate management to the patient (Johnstone, 2007). This weakness was indicated through a report by NCEPOD (2005), which revealed that for many patients, the EWS was not calculated, recorded and the appropriate algorithm was not acted upon. In some cases, serious omissions in management were made in the hurry to take the sick patient to the critical care unit, including inadequate intravenous fluid administration. Although EWS has a simplistic scoring method, inaccuracies and critical mistakes have been made by healthcare staff with its implementation. Prytherch et al. (2006) and Smith & Oakey. (2006) found errors in the calculation of scores by staff that could potentially have lead to a failure in identifying patients in need of additional care. If patients not in immediate need of critical care or interventions were stepped up to a higher unit due to errors in the score calculation, work load and the health care burden could also potentially increase unnecessarily (Cuthbertson, 2007). Therefore, it has been suggested that healthcare professionals should not rely solely on these tools, rather, they should be used in conjunction with their professional judgement, clinical acumen and experience, in order to ensure that patients are assessed into the appropriate category of illness severity and need of intervention (Tait, 2010). The benefits of the MEWS system have also been offset by reports that it has not been used consistently in all cases (Subbe et al, 2001). About one in four hospitals today do not use any form of T&T system. The vital signs recorded during routine patient monitoring in the general wards of many hospitals include blood pressure, temperature and pulse rate, however, respiratory rate is often not recorded (NCEPOD, 2005). This is a significant issue, as increasing respiratory rate offers an early and sensitive indicator for patients’ deterioration. In addition, many centres maintain poor-quality medical records of seriously ill inpatients, often with no documentation regarding resuscitation decisions, even for patients who have been fall under the category of high risk of deterioration (NCEPOD, 2005). It has been suggested that there is a prevailing deficiency in the provision of clear instructions, training and familiarity of the general ward nursing staff regarding the EWS system, especially on when to call for assistance. Due to this, patient deterioration is often not detected early, or rapid interventions are not taken (NCEPOD, 2005). This leads to an entirely preventable increase in critical care admission delays and patient mortality. Despite some conflicting evidence, the literature provides sufficient and quantifiable evidence of the effectiveness of EWS (Johnstone et al, 2007). EWS provides an effective method of monitoring patients’ clinical progress, and offers a specific graded response strategy that can be easily incorporated and implemented in existing health care systems (NICE, 2007). It has been accepted by many United Kingdom (UK) hospitals that the use of T&T systems improves care of the deteriorating patient. In conclusion, early warning scores or ‘track and trigger’ systems are useful tools for the facilitation of early identification of destabilization and deterioration of an inpatient’s clinical status, as abnormal changes in physiological parameters such as vital signs can frequently be recognised prior to the onset of a critical illness, or before the patient goes into irreversible deterioration. These tools have been included in the recommendations by national healthcare policies for several years, and studies have consistently demonstrated that their use is associated with reduced rates of cardiac arrest, mortality and morbidity in hospitals and ultimately better patient care. Alternatively, some reports show these tools to fail in improving patient outcomes due to several factors, including incomplete implementation of the system, poor documentation of EWS scores, and a lack of knowledge among healthcare staff regarding the recording of vital signs and calculation of scores. Therefore, to make ‘track and trigger’ systems truly effective, healthcare staff needs to be trained in detecting patients’ deterioration, and be familiar with using the scoring system and trigger procedure. Overall, early warning or ‘track and trigger’ systems are useful for the early identification of patients’ deterioration. Read More