A number of seminal studies during the late 1990’s established that in-hospital cardiac arrest, or decline in the patient’s clinical condition to a critical point, was generally preceded by a period of time when the physiological status of the patient was abnormal. This could be seen in the measurements of respiratory rate, blood pressure, heart rate and temperature (McQuillan et al., 1998; McGloin et al., 1999;
Goldhill et al., 1999). Following this, a number of patient observation tools were developed (Morgan et al., 1997; Subbe et al., 2001) which used simple scoring of physiological vital signs measurements to identify patients at risk of deterioration.
The tools were introduced to improve the safety of acutely ill patients in hospital by improving the ability of nurses to recognise clinical deterioration (Donohue &
Endacott, 2010) and have continued to gain momentum in their implementation (NICE, 2007; NPSA 2007) and development (RCP 2012). The tools are generally referred to as early warning scores or track and trigger tools.
35 Undoubtedly, one of the key skill sets for any nurse working in an acute environment is the ability to measure, interpret and monitor the physiological vital signs of the patient. These include respiratory rate, blood pressure, heart rate and temperature. The monitoring of vital signs is critical in the early recognition of clinical deterioration in the patient. A subtle move away from the normal parameters for each of the vital signs may provide an early indication of deterioration in the patient (Subbe et al., 2001). Recognition has been given to the fact that the monitoring of vital signs in the patient is essential in the identification of the deteriorating patient, with the emphasis on the collection of objective, measurable data. In 2007, both the National Patient Safety Agency (NPSA, 2007) and the National Institute for Health and Clinical Excellence (NICE, 2007) published recommendations for the monitoring of patients in hospital using track and trigger tools, now more commonly referred to as EWS. Additionally, in 2010 the European resuscitation council included the use of EWS in the guidelines for resuscitation, including it in the first link in the chain of survival (Nolan et al., 2010), reflecting the significance of recognising deterioration in patients at an early stage and responding quickly to avert further decline in the patient’s condition.
The EWS document replaces the traditional nursing observations or bedside observations chart, commonly referred to as the TPR (temperature, pulse and respirations) chart. There are many EWS tools in use around the UK with no standardisation currently applied. Whilst in the role of consultant nurse, one of the objectives of the role was to develop and introduce an EWS tool to the medical directorate in the hospital. At that time, gaining consensus across the various
36 directorates was an enormous challenge since at any one time there were three adult EWS tools in use. Eventually, these were developed into a single nursing observation tool for adults (see appendix i).
The RCP (2012) argue that there is a lack of consistency in approach to patient monitoring using these tools, which are very different and incompatible with each other. This leads to confusion for staff when they move between clinical areas employing dissimilar tools, different scoring, triggers and medical response measures in operation. The EWS tools are generally comparable in their design, based on a simple scoring system applied to the measurement of the patient’s vital signs and generally include the respiratory rate (per minute), systolic blood pressure, heart rate (per minute), temperature and level of consciousness. A numerical score is applied to each vital sign, with higher scores applied where measurements fall further outside the normal parameters expected. The scores are then added together and documented on the EWS chart. If the score reaches a trigger point, the nurse is alerted to a predetermined course of action, which may be to increase the frequency of observations or to call for medical review (Goldhill, 2005). As such, the EWS is intended to identify subtle physiological changes in the patient’s clinical status over time, but dictates a set response, thus disregarding the nurse’s clinical expertise in patient observation. Whilst the EWS tool involves the simple adding of numerical values to generate the EWS score, studies have found significant failings in the correct application of the tools in practice (Donohue & Endacott, 2010) demonstrating the limitations of such tools in practice, which oversimplify the complexities of assessing acutely ill patients.
37 2.2 Limitations of early warning score observation tools
Considerable emphasis has been given to the implementation of EWS tools in the UK and Australasia, in an attempt to improve outcomes and mortality for acutely ill patients in hospital (NICE, 2007; Chaboyer, et al., 2008; Kyriacos, et al., 2011).
However, these tools have significant limitations which appear to have been overlooked by those endorsing their application. Few EWS tools have been formally validated (Kyriacos et al., 2011; RCP, 2012) and there is no single validated tool which can be applied across clinical disciplines or conditions (Goldhill, 2005; Bell et al., 2006; RCP, 2012).
Huge variation in the EWS tools used across the UK risk confusion among nursing and medical staff when working in different areas. The array of EWS tools currently employed applies a variety of physiological parameters to derive their score. This means that staff must appreciate local variations in approach and be taught how to use the local EWS tool whenever moving hospital, and sometimes even if moving between departments in the same hospital, as the scoring systems may differ. To compound this problem further, the monitoring of vital signs is often undertaken by a nursing support assistant, as opposed to a Registered Nurse (Wheatley, 2006), having differing levels of knowledge and understanding which may impact upon the timeliness of intervention. Nurses have been found to fail to respond to abnormal signs (Odell et al., 2009) and to fail to adequately report signs of deterioration to medical colleagues (Andrews & Waterman, 2005; Odell et al., 2009). EWS tools focus largely on the measurement of objective data using routine measurements of vital signs, with little if any reference to the use of visual
38 or qualitative nursing observations of the patient. However, EWS tools generally provide a caveat to allow for clinical concern, a subjective finding, which strongly suggests that these observations are considered significant (see appendices i and x for examples of EWS tools).
Increasing awareness of nurses’ failure to recognise patient deterioration has seen widespread implementation of EWS tools. Georgaka et al. (2012) argue that evidence for the clinical effectiveness of these tools is limited, yet they have been widely adopted among the acute NHS hospital trusts and endorsed by government agencies (NPSA, 2007; NICE, 2007). The EWS, when applied effectively, uses objective measurable data to track patients’ progress and to trigger a response when vital signs become significantly abnormal. However, concerns have been raised that EWS are measured infrequently and that measurements of vital signs are incomplete and inaccurately recorded (Chellel et al., 2002, Goldhill, 2005; Endacott et al., 2007). Furthermore, Cuthbertson et al.
(2007) argue that although the physiological variables included in early warning scoring systems ‘seem clinically intuitive and rational, they include best-guess physiological variable ranges and cut points and lack clinical validation’ (p 403).
Personal experience of using an EWS tool found that there were often patients who presented with abnormal vital signs but which were considered safe and normal for that particular individual despite ‘triggering’ on the EWS tool parameters. This would commonly occur in patients with chronic obstructive airways disease which affected the respiratory rate and those with underlying cardiac complaints affecting the heart rate and blood pressure.
39 Gao et al. (2007) argue that the structure, model and effectiveness of scoring systems vary, that hospitals have developed their own scoring systems and that evidence of reliability, validity and utility is lacking. A systematic review of 25 published early warning observation tools stated that the specificities and negative predictive values of these systems were found to be acceptable, but that positive predictive values was found to be unacceptably poor (Gao et al., 2007). More importantly, some have argued that these types of early warning observation tools are inadequate predictors of hospital mortality, cardio-respiratory arrest, and admission to critical care (Oakey & Slade, 2006; Gao et al.,2007), suggesting that a new approach to the nursing and observation of acutely ill patients is needed.
EWS tools continue to be scrutinised and refined, with recommendations from the RCP for the implementation of single, standardised, validated tool across the NHS (RCP 2012). The RCP National Early Warning Score (see appendix x) incorporates additional scores for supplemental oxygen therapy and for oxygen saturation, which when added together provide an overall score to gauge the physiological status of the patient. The tool itself is used in the same manner as other EWS tools. This strongly suggests that the current approach of locally derived EWS tools has failed to impact sufficiently on patient outcome. The RCP (2012) argue that early detection of acute illness is only one of a triad of determinants of clinical outcome for patients. In isolation, monitoring of the EWS score is ineffective. Timeliness and competency of clinical response are deemed to be equally important in the recognition of the acutely ill patient. An obvious difficulty with this is determination of what constitutes a timely and/or competent
40 clinical response since many hospitals do not have access to critical care outreach services or medical emergency teams (RCP, 2012).
The professional nursing body has accepted and contributed to the development, implementation and evaluation of existing EWS tools but has thus far failed to take ownership of this fundamental element of nursing practice which has been largely driven by critical care. It is argued that nursing expertise and opinion is essential to further determine the direction of nursing observation of patients and that ownership of this must be brought back to the clinical face of nursing practice.
Furthermore, the complexities involved in the nursing observation of patients cannot be captured or replicated by an objective measurement tool, since elements of nursing observations are largely unquantifiable and are informed by various sources of knowledge. This is borne out by the literature discussed further in sections 2.4, 2.5 and in the findings, presented in section 5.2.