The impact of the use of the Early Warning Score (EWS) on patient outcomes: A systematic review

Background

Acute deterioration in critical ill patients is often preceded by changes in physiological parameters, such as pulse, blood pressure, temperature and respiratory rate. If these changes in the patient's vital parameters are recognized early, excess mortality and serious adverse events (SAEs) such as cardiac arrest may be prevented. The Early Warning Score (EWS) is a scoring system which assists with the detection of physiological changes and may help identify patients at risk of further deterioration.

Objectives

The aim of this systematic review is to evaluate the impact of the use of the Early Warning Score (EWS) on particular patient outcomes, such as in-hospital mortality, patterns of intensive care unit admission and usage, length of hospital stay, cardiac arrests and other serious adverse events of adult patients on general wards and in medical admission units.

Design and setting

Systematic review of studies identified from the bibliographic databases of PubMed, EMBASE.com and The Cochrane Library.

Selection criteria

All controlled studies which measured in-hospital mortality, ICU mortality, serious adverse events (SAEs), cardiopulmonary arrest, length of stay and documentation of physiological parameters which used a EWS on the ward or the emergency department to identify patients at risk were included in the review.

Data collection and analysis

Three reviewers (NA, AT and EH) independently screened all potentially relevant titles and abstracts for eligibility, by using a standardized data-worksheet. Meta-analysis was not possible due to heterogeneity.

Main results

Seven studies met the inclusion criteria. The results of our included studies were mixed, with a positive trend towards better clinical outcomes following the introduction of the EWS chart, sometimes coupled with an outreach service.Six of the seven included studies used mortality as an endpoint: two of these studies reported no significant difference in in-hospital mortality rate; two found a significant reduction of in-hospital mortality; two other studies described a trend towards improved survival. Although, both ICU mortality and serious adverse events were not significantly improved, there was a trend towards reduction of these endpoints after introduction of the EWS. However only two studies looked respectively at each endpoint.There were conflicting results concerning cardiopulmonary arrests. One study found a reduction in the incidence of cardiac arrest calls as well as in the mortality of patients who underwent CPR, while another one found an increased incidence of cardio-pulmonary arrests. Neither study met all methodological quality criteria.

Conclusion

The EWS itself is a simple and easy to use tool at the bedside, which may be of help in recognizing patients with potential for acute deterioration. Coupled with an outreach service, it may be used to timely initiate adequate treatment upon recognition, which may influence the clinical outcomes positively. However, the use of adapted forms of the EWS together with different thresholds, poor or inadequate methodology makes it difficult in drawing comparisons. A general conclusion can thus not be generated from the lack of use of a single standardized score and the use of different populations. In future large multi-centre trials using one standardized score are needed also in order to facilitate comparison.     

Monoclonal and polyclonal antibodies both block and enhance transmission of human Plasmodium vivax malaria

Antibodies against gametes of the malarial parasite inhibit the development of the parasite in the mosquito and curtail the transmission of malaria. We now report that a monoclonal antibody against gametes of the human malaria pathogen Plasmodium vivax and antibodies induced during natural infections of P. vivax in humans which suppress infectivity of the parasites to the vector at high concentrations can, at lower concentrations, have the opposite effect and enhance the level of malaria infection in the mosquitoes. Infectivity enhancing effects of up to 12-fold were demonstrated when a transmission blocking monoclonal antibody and immune human sera were diluted, in some undiluted immune human sera, and in the sera of vivax malaria patients during convalescence after drug cure.     

Cognitive function and apolipoprotein E in very old adults: findings from the Nun Study

OBJECTIVES: The epsilon4 allele of apolipoprotein E (APOE) has been associated with Alzheimer' s disease and with milder forms of cognitive impairment. We investigated the possibility that the absence of the epsilon4 allele may predict the maintenance of high cognitive function among very old individuals. METHODS: Our data are from the Nun Study, a longitudinal study of aging and Alzheimer's disease in 678 Catholic sisters. All sisters participate in annual functional exams that include the Consortium to Establish a Registry for Alzheimer's Disease (CERAD) battery of cognitive tests. High cognitive function was defined as intact scores on five of the CERAD tests. A total of 241 participants aged 75 to 98 met this criterion at the first exam. RESULTS: Findings showed that 62% of the 241 participants maintained intact scores on the five CERAD tests throughout their participation in the study. Life table analyses indicated that those without the APOE epsilon4 allele spent more time with intact cognitive function than those with the epsilon4 allele (p = .007). Cox regression analyses indicated that those without the epsilon4 allele had half the risk of losing their intact status during the study when compared with those with the epsilon4 allele (p < .01). DISCUSSION: Our findings suggest that the APOE epsilon4 allele may be included among the variables that predict high cognitive function in cognitively intact, very old adults. Although the presence or absence of the epsilon4 allele is known to be related to the risk of dementia, it also appears to be related to maintaining high levels of cognitive function in old age.     

The analytical sensitivity of Tc99m radionuclide ‘milk’ scanning in the detection of gastro-oesophageal reflux

The analytical sensitivity of radionuclide ‘milk’ scans for detecting gastro-oesophageal reflux (GOR) has been assessed using an in vitro simulation test. Five factors were found to affect the ability to detect simulated reflux: isotope concentration, absolute gamma camera sensitivity, absorber thickness overlying the ‘oesophagus’ and volume and duration of reflux. We found that a critical volume-duration product must be exceeded for reflux to be detected. Radionuclide milk scanning appears to be much less sensitive in detecting transient events like GOR than might be expected from previously reported static simulation studies.     

Synthesis of [13C6]primaquine

In support of a program to identify toxic metabolites of the antimalarial, primaquine, its [¹³C₆] analog was prepared from [¹³C₆] anisole in seven steps.