Caroline Kovacs

Development and validation of a decision tree early warning score based on routine laboratory test results for the discrimination of hospital mortality in emergency medical admissions

AIM OF STUDY To build an early warning score (EWS) based exclusively on routinely undertaken laboratory tests that might provide early discrimination of in-hospital death and could be easily implemented on paper. MATERIALS AND METHODS Using a database of combined haematology and biochemistry results for 86,472 discharged adult patients for whom the admission specialty was Medicine, we used decision tree (DT) analysis to generate a laboratory decision tree early warning score (LDT-EWS) for each gender. LDT-EWS was developed for a single set (n=3496) (Q1) and validated in 22 other discrete sets each of three months long (Q2, Q3…Q23) (total n=82,976; range of n=3428 to 4093) by testing its ability to discriminate in-hospital death using the area under the receiver-operating characteristic (AUROC) curve. RESULTS The data generated slightly different models for male and female patients. The ranges of AUROC values (95% CI) for LDT-EWS with in-hospital death as the outcome for the validation sets Q2-Q23 were: 0.755 (0.727-0.783) (Q16) to 0.801 (0.776-0.826) [all patients combined, n=82,976]; 0.744 (0.704-0.784, Q16) to 0.824 (0.792-0.856, Q2) [39,591 males]; and 0.742 (0.707-0.777, Q10) to 0.826 (0.796-0.856, Q12) [43,385 females]. CONCLUSIONS This study provides evidence that the results of commonly measured laboratory tests collected soon after hospital admission can be represented in a simple, paper-based EWS (LDT-EWS) to discriminate in-hospital mortality. We hypothesise that, with appropriate modification, it might be possible to extend the use of LDT-EWS throughout the patients hospital stay.

A Comparison of the Ability of the Physiologic Components of Medical Emergency Team Criteria and the U.k. National Early Warning Score to Discriminate Patients at Risk of a Range of Adverse Clinical Outcomes.

Objective:To compare the ability of medical emergency team criteria and the National Early Warning Score to discriminate cardiac arrest, unanticipated ICU admission and death within 24 hours of a vital signs measurement, and to quantify the associated workload. Design:Retrospective cohort study. Setting:A large U.K. National Health Service District General Hospital. Patients:Adults hospitalized from May 25, 2011, to December 31, 2013. Interventions:None. Measurements and Main Results:We applied the National Early Warning Score and 44 sets of medical emergency team criteria to a database of 2,245,778 vital signs sets (103,998 admissions). The National Early Warning Score’s performance was assessed using the area under the receiver-operating characteristic curve and compared with sensitivity/specificity for different medical emergency team criteria. Area under the receiver-operating characteristic curve (95% CI) for the National Early Warning Score for the combined outcome (i.e., death, cardiac arrest, or unanticipated ICU admission) was 0.88 (0.88–0.88). A National Early Warning Score value of 7 had sensitivity/specificity values of 44.5% and 97.4%, respectively. For the 44 sets of medical emergency team criteria studied, sensitivity ranged from 19.6% to 71.2% and specificity from 71.5% to 98.5%. For all outcomes, the position of the National Early Warning Score receiver-operating characteristic curve was above and to the left of all medical emergency team criteria points, indicating better discrimination. Similarly, the positions of all medical emergency team criteria points were above and to the left of the National Early Warning Score efficiency curve, indicating higher workloads (trigger rates). Conclusions:When medical emergency team systems are compared to a National Early Warning Score value of greater than or equal to 7, some medical emergency team systems have a higher sensitivity than National Early Warning Score values of greater than or equal to 7. However, all of these medical emergency team systems have a lower specificity and would generate greater workloads.

Comparison of the National Early Warning Score in non-elective medical and surgical patients

The National Early Warning Score (NEWS) is used to identify deteriorating patients in hospital. NEWS is a better discriminator of outcomes than other early warning scores in acute medical admissions, but it has not been evaluated in a surgical population. The study aims were to evaluate the ability of NEWS to discriminate cardiac arrest, death and unanticipated ICU admission in patients admitted to surgical specialties, and to compare the performance of NEWS in admissions to medical and surgical specialties.

What impact does nursing care left undone have on patient outcomes? Review of the literature

Aims and objectives Systematic review of the impact of missed nursing care on outcomes in adults, on acute hospital wards and in nursing homes. Background A considerable body of evidence supports the hypothesis that lower levels of registered nurses on duty increase the likelihood of patients dying on hospital wards, and the risk of many aspects of care being either delayed or left undone (missed). However, the direct consequence of missed care remains unclear. Design Systematic review. Methods We searched Medline (via Ovid), CINAHL (EBSCOhost) and Scopus for studies examining the association of missed nursing care and at least one patient outcome. Studies regarding registered nurses, healthcare assistants/support workers/nurses’ aides were retained. Only adult settings were included. Because of the nature of the review, qualitative studies, editorials, letters and commentaries were excluded. PRISMA guidelines were followed in reporting the review. Results Fourteen studies reported associations between missed care and patient outcomes. Some studies were secondary analyses of a large parent study. Most of the studies used nurse or patient reports to capture outcomes, with some using administrative data. Four studies found significantly decreased patient satisfaction associated with missed care. Seven studies reported associations with one or more patient outcomes including medication errors, urinary tract infections, patient falls, pressure ulcers, critical incidents, quality of care and patient readmissions. Three studies investigated whether there was a link between missed care and mortality and from these results no clear associations emerged. Conclusions The review shows the modest evidence base of studies exploring missed care and patient outcomes generated mostly from nurse and patient self‐reported data. To support the assertion that nurse staffing levels and skill mix are associated with adverse outcomes as a result of missed care, more research that uses objective staffing and outcome measures is required. Relevance to clinical practice Although nurses may exercise judgements in rationing care in the face of pressure, there are nonetheless adverse consequences for patients (ranging from poor experience of care to increased risk of infection, readmissions and complications due to critical incidents from undetected physiological deterioration). Hospitals should pay attention to nurses’ reports of missed care and consider routine monitoring as a quality and safety indicator.

Response to 'Inpatient illness severity surveys provide essential data for planning capacity and managing patient flow in the acute hospital setting' (J of Intensive Care Soc 2016; 17: 196-201)

citing two inappropriate references. However, Morgan et al. published the first early warning score (EWS) in 1997 and Stenhouse et al. described the first ‘modified’ version (i.e. MEWS) in 2000. Since then, a confusing array of different EWS – many named MEWS (modified EWS) – has been introduced into clinical practice. In 2012, the Royal College of Physicians of London (RCP) developed NEWS, which was based on a minor modification of the VitalPAC EWS (ViEWS). NEWS has greater discrimination for predicting patients at risk an adverse outcome within 24 h than other published EWS systems including the Gardner-Thorpe MEWS used in Garland et al.’s study (c-statistic: NEWS 0.87, Gardner-Thorpe MEWS 0.83). Garland et al. also suggest MEWS has been ‘‘. . . renamed as the National Early Warning Score (NEWS) by NHS England . . .,’’ although this is not supported by the references they cite. We are unaware of any such act. Moreover, as NEWS and the many different versions of MEWS vary in their composition and performance, this would be inappropriate. Garland et al. also state ‘‘. . .Current care pathways for patients in the MEWS systems recommend escalation, if the MEWS rises above 5 . . .,’’ citing the RCP report. It is important to note that different early warning systems vary substantially in terms of how the aggregate score maps to the risk of mortality or other adverse events (e.g. unanticipated ICU admission). Consequently, the score threshold of 55 used to trigger a prompt clinical review of patients recommended by the RCP applies only if NEWS is used. It is also worth noting that the score thresholds suggested for NEWS by the RCP working group were arrived at pragmatically, based on the associated risk of adverse outcomes and the expected workload generated in a single hospital. A balance must always be achieved between the benefits of the early clinical assessment of patients with high/rising EWS values and the disadvantages of ‘‘alarm fatigue.’’ The RCP working group also notes: ‘‘. . . the most effective way to formally evaluate the effectiveness of NEWS at improving clinical outcomes was to implement it into practice and evaluate its performance on a large scale . . .’’ Unfortunately, there are no large-scale evaluations of the impact of using different thresholds to trigger a clinical response.

Outreach and early warning systems for the prevention of intensive care admission and death of critically ill adult patients on general hospital wards

This is a commentary on a Cochrane review1 concerning Outreach and Early Warning Systems for the prevention of Intensive Care admission and death of critically ill adult patients on general hospital wards. Many in-hospital deaths or other adverse events might be predicted and hence avoided because abnormal vital signs observations can be detected some six to 24 hours prior to an adverse event. However the clinical importance of these is often missed. This might be because staff do not recognise the clinical urgency, fail to seek advice, or lack knowledge or skills in resuscitation. Failure to recognise the severity of the patient’s situation may result in unanticipated admission to Intensive Care, longer length of stay, cardiac arrest or death.