Background Research across the formal, natural and social sciences has greatly expanded our knowledge about complex systems in recent decades, informing a broadly inclusive, crossdisciplinary conceptual framework referred to as Systems Thinking (ST). Its use in public health is rapidly increasing, although there remains a poor understanding of how these ideas have been imported, adapted and elaborated by public health research networks worldwide. Method This review employed a mixed methods approach to narrate the development of ST in public health. Tabulated results from a literature search of the Web of Science Core Collection database were used to perform a bibliometric analysis and literature review. Annual publication counts and citation scores were used to analyse trends and identify popular and potential 'landmark' publications. Citation network and co-authorship network diagrams were analysed to identify groups of articles and researchers in various network roles. Results Our search string related to 763 publications. Filtering excluded 208 publications while citation tracing identified 2 texts. The final 557 publications were analysed, revealing a nearexponential growth in literature over recent years. Half of all articles were published after 2010 with almost a fifth (17.8%) published in 2014. Bibliographic analysis identified five distinct citation and co-authorship groups homophilous by common geography, research focus, inspiration or institutional affiliation. As a loosely related set of sciences, many public health researchers have developed different aspects of ST based on their underlying perspective. Early studies were inspired by Managementrelated literature, while later groups adopted a broadly inclusive understanding which incorporated related Systems sciences and approaches. Conclusion ST is an increasingly popular subject of discussion within public health although its understanding and approaches remain unclear. Briefly tracing the introduction and development of these ideas and author groups in public health literature may provide clarity and opportunities for further learning, research and development.

ObjectiveTo derive and validate a new clinical prediction rule to risk-stratify emergency department (ED) patients admitted with suspected sepsis.DesignRetrospective prognostic study of prospectively collected data.SettingED.ParticipantsPatients aged ≥18 years who met two Systemic Inflammatory Response Syndrome criteria or one Red Flag sepsis criteria on arrival, received intravenous antibiotics for a suspected infection and admitted.Primary outcome measureIn-hospital all-cause mortality.MethodThe data were divided into derivation and validation cohorts. The simplified-Mortality in Severe Sepsis in the ED score and quick-SOFA scores, refractory hypotension and lactate were collectively termed ‘component scores’ and cumulatively termed the ‘Risk-stratification of ED suspected Sepsis (REDS) score’. Each patient in the derivation cohort received a score (0–3) for each component score. The REDS score ranged from 0 to 12. The component scores were subject to univariate and multivariate logistic regression analyses. The receiver operator characteristic (ROC) curves for the REDS and the components scores were constructed and their cut-off points identified. Scores above the cut-off points were deemed high-risk. The area under the ROC (AUROC) curves and sensitivity for mortality of the high-risk category of the REDS score and component scores were compared. The REDS score was internally validated.Results2115 patients of whom 282 (13.3%) died in hospital. Derivation cohort: 1078 patients with 140 deaths (13%). The AUROC curve with 95% CI, cut-off point and sensitivity for mortality (95% CI) of the high-risk category of the REDS score were: derivation: 0.78 (0.75 to 0.80); ≥3; 85.0 (78 to 90.5). Validation: 0.74 (0.71 to 0.76); ≥3; 84.5 (77.5 to 90.0). The AUROC curve and the sensitivity for mortality of the REDS score was better than that of the component scores. Specificity and mortality rates for REDS scores of ≥3, ≥5 and ≥7 were 54.8%, 88.8% and 96.9% and 21.8%, 36.0% and 49.1%, respectively.ConclusionThe REDS score is a simple and objective score to risk-stratify ED patients with suspected sepsis.

Background Early treatment is advocated in the management of patients with suspected sepsis in the emergency department (ED). We sought to understand the association between the ED treatments and outcome in patients admitted with suspected sepsis. The treatments studied were: (i) the time to antibiotics, where time zero is the time the patient was booked in which is also the triage time; (ii) the volume of intravenous fluid (IVF); (iii) mean arterial pressure (MAP) after 2000 ml of IVF and (iv) the final MAP in the ED. Methods We performed a retrospective analysis of the ED database of patients aged ≥ 18 year who met two SIRS criteria or one red flag sepsis criteria on arrival, received intravenous antibiotics for a suspected infection and admitted between 8th February 2016 and 31st August 2017. The primary outcome measure was all-cause in-hospital mortality. The four treatments stated above were controlled for severity of illness and subject to multivariate logistic regression and Cox proportional-hazard regression to identify independent predictors of mortality. Results Of the 2,066 patients studied 272 (13.2%) died in hospital. The median time to antibiotics was 48 (interquartile range 30–82) minutes. The time to antibiotics was an independent predictor of mortality only in those who developed refractory hypotension (RH); antibiotics administered more than 55 mins after arrival was associated with an odds ratio (OR) for mortality of 2.75 [95% confidence interval (CI) 1.22–6.14]. The number-needed-to-treat was 4. IVF > 2000 ml (95% CI > 500– > 2100), except in RH, and a MAP ≤ 66 mmHg after 2000 ml of IVF were also independent predictors of mortality. The OR for mortality of IVF > 2,000 ml in non-RH was 1.80 (95% CI 1.15–2.82); Number-needed-to-harm was 14. The OR for morality for a MAP ≤ 66 mmHg after 2000 ml of IVF was 3.42 (95% CI 2.10–5.57). A final MAP < 75 mmHg in the ED was associated with, but not an independent predictor of mortality. An initial systolic blood pressure of < 100 mmHg has a sensitivity of 63.3% and specificity of 88.4% for the development of RH. Conclusion In this study, antibiotics were found to be time-critical in RH. Intravenous fluids > 2000 ml (except in RH) and a MAP ≤ 66 mmHg after 2000 ml of IVF were also independent predictors of mortality.

Aims/Objectives/BackgroundEarly treatment is advocated in the management of patients with suspected sepsis. We sought to understand the association between the emergency department (ED) treatments and outcome in these patients. The treatments studied were: (i) the time to antibiotics, (ii) the volume of intravenous fluid (IVF), (iii) mean arterial pressure (MAP) after 2,000 ml of IVF and (iv) the final MAP in the ED.Methods/DesignA retrospective analysis of the ED database of adult patients who met two SIRS criteria or one red flag sepsis criteria on arrival, received intravenous antibiotics for a suspected infection and admitted between February 2016 and August 2017, was performed. The primary outcome measure was all-cause in-hospital mortality. The four treatments stated above were controlled for severity of illness and subject to multivariate logistic regression and Cox proportional-hazard regression to identify independent predictors of mortality.Results/ConclusionsOf the 2,066 patients studied 272 (13.2%) died in hospital. The median time to antibiotics was 48 (Interquartile range 30–82) minutes. The time to antibiotics was an independent predictor of mortality only in those who developed refractory hypotension (RH); antibiotics administered more than 55 mins after arrival was associated with an odd-ratio (OR) for mortality of 2.75 [95% confidence interval (CI) 1.22–6.14]. The number-needed-to-treat was 4. IVF >2,000 ml (95%CI >500->2,100), except in RH, and a MAP≤66 mmHg after 2,000 mls of IVF were also independent predictors of mortality. The OR for mortality of IVF>2,000 ml in non-RH was 1.80 (95%CI 1.15–2.82); Number-needed-to-harm was 14. The OR for morality for a MAP≤66 mmHg after 2,000 ml of IVF was 3.42 (95%CI 2.10–5.57). A final MAP<75 mmHg in the ED was associated with, but not an independent predictor of mortality.Antibiotics were time-critical only in refractory hypotension. Intravenous fluids >2,000 mls in non-RH and a MAP≤66 mmHg after 2,000 ml of IVF were also independent predictors of mortality.