Optimization of Site Selection for Emergency Medical Facilities considering the SEIR Model.

Since the outbreak of COVID-19, the rapid construction and operation of Wuhan Vulcan Mountain Hospital and Raytheon Hospital have attracted positive responses from local and international observers. At the same time, it has also highlighted the urgency for the construction of emergency medical facilities for public health emergencies. Before construction, the practical location of medical facilities is the basis for improving the city's emergency management ability. Based on the classic susceptible, exposed, infected, and recovered (SEIR) epidemic model and epidemic data in Guangzhou, we established a multi-stage time-delay SEIR epidemic model that is suitable for epidemic research in Guangzhou. According to the results of the model, the five areas with the highest number of infected patients were identified, which included Baiyun District, Panyu District, Haizhu District, Tianhe District, and Zengcheng District. We then centralized infected individuals at five demand points. Based on the distribution of these points and by combining the characteristics of the emergency medical facilities, we built and solved the set covering location decision model, and considered the economy, society, and environment as the starting points to optimize the site location. Finally, based on simulations, we concluded that appropriate site selection can increase the time required to reach the maximum number of patients and reduce the proportion of infected and exposed people by 11.3% and 1.11%, respectively. This is indicative of the effectiveness of the site selection model and the rational selection of facility points in this study. It solves the optimization problem of the location decision of emergency medical facilities for public health emergencies in China, and also provides some valuable references for site selection decisions of emergency medical facilities in other areas.

A meta-analysis of the relationship between foot local characteristics and major lower extremity amputation in diabetic foot patients.

OBJECTIVE: To clarify and quantify risk factors among local characteristics of the foot for major amputation in diabetic foot patients. METHODS: Articles published before January 2018 on PubMed and Embase were conducted observational studies about risk factors for major amputation in patients with diabetic foot were retrieved and systematically reviewed by using Stata 12.0 statistical software. RESULTS: A total of 4668 major amputees and 65 831 controls were reported in 18 observational studies. Across the studies, the overall odds ratios (ORs) and 95% confidence intervals (CIs) of significant risk factors are ulcer reaching bone (OR, 11.796; 95% CI, 6.905-20.152), gangrene (OR, 6.487; 95% CI, 4.088-10.293), hindfoot position (OR, 3.913; 95% CI, 2.254-6.795), decreased ankle-brachial index (ABI) (OR, 2.522; 95% CI, 1.805-3.523), infection (OR, 2.516; 95% CI, 1.708-3.706), peripheral arterial disease (PAD) (OR, 2.114; 95% CI, 1.326-3.372). While there is no significant difference in the size of the ulcer, neuropathy, Charcot foot, osteomyelitis and intermittent claudication (OR, 1.15; 95% CI, 0.85-1.54). CONCLUSION: Factors among local characteristics of the foot associated with major amputation in patients with diabetic foot are the ulcer reaching bone, gangrene, hindfoot position, decreased ABI, infection, and PAD, a negative risk factor for the risk of amputation. Further studies are required to provide more details of foot local characteristics.