Linear formulation for the Maximum Expected Coverage Location Model with fractional coverage

Since ambulance providers are responsible for life-saving medical care at the scene in emergency situations and since response times are important in these situations, it is crucial that ambulances are located in such a way that good coverage is provided throughout the region. Most models that are developed to determine good base locations assume strict 0-1 coverage given a fixed base location and demand point. However, multiple applications require fractional coverage. Examples include stochastic, instead of fixed, response times and survival probabilities. Straightforward adaption of the well-studied MEXCLP to allow for coverage probabilities results in a non-linear formulation in integer variables, limiting the size of instances that can be solved by the model. In this paper, we present a linear integer programming formulation for the problem. We show that the computation time of the linear formulation is significantly shorter than that for the non-linear formulation. As a consequence, we are able to solve larger instances. Finally, we will apply the model, in the setting of stochastic response times, to the region of Amsterdam, the Netherlands

Keperluan tabung pampasan tanah di Malaysia

Kertas keja membincangkan tentang keperluan menyediakan tabung jaminan/pampasan tanah di Malaysia memandangkan ramai pemilik tanah yang kehilangan tanah akibat dari penipuan tanpa berpeluang menuntut gantirugi.Beberapa pendapat daripada pengamal undang-undang menyokong cadangan mengadakan tabung jaminan tanah ini di Malaysia.Walaupun ia tidak memberikan gantirugi kepada pemilik tanah secara keseluruhan, akan tetapi sekurang-kurangnya ia dapat melegakan mereka setelah mendapat pampasan dari kerajaan

Relationship between primary stroke center volume and time to endovascular thrombectomy in acute ischemic stroke

Background and purpose We investigated whether the annual volume of patients with acute ischemic stroke referred from a primary stroke center (PSC) for endovascular treatment (EVT) is associated with treatment times and functional outcome. Methods We used data from the Multicenter Randomized Clinical Trial of Endovascular Treatment for Acute Ischemic Stroke in the Netherlands (MR CLEAN) registry (2014-2017). We included patients with acute ischemic stroke of the anterior circulation who were transferred from a PSC to a comprehensive stroke center (CSC) for EVT. We examined the association between EVT referral volume of PSCs and treatment times and functional outcome using multivariable regression modeling. The main outcomes were time from arrival at the PSC to groin puncture (PSC-door-to-groin time), adjusted for estimated ambulance travel times, time from arrival at the CSC to groin puncture (CSC-door-to-groin time), and modified Rankin Scale (mRS) score at 90 days after stroke. Results Of the 3637 patients in the registry, 1541 patients (42%) from 65 PSCs were included. Mean age was 71 years (SD +/- 13.3), median National Institutes of Health Stroke Scale score was 16 (interquartile range [IQR]: 12-19), and median time from stroke onset to arrival at the PSC was 53 min (IQR: 38-90). Eighty-three percent had received intravenous thrombolysis. EVT referral volume was not associated with PSC-door-to-groin time (adjusted coefficient: -0.49 min/annual referral, 95% confidence interval [CI]: -1.27 to 0.29), CSC-door-to-groin time (adjusted coefficient: -0.34 min/annual referral, 95% CI: -0.69 to 0.01) or 90-day mRS score (adjusted common odds ratio: 0.99, 95% CI: 0.96-1.01). Conclusions In patients transferred from a PSC for EVT, higher PSC volumes do not seem to translate into better workflow metrics or patient outcome.Neuro Imaging Researc

Dutch trauma system performance: are injured patients treated at the right place?

Background: The goal of trauma systems is to match patient care needs to the capabilities of the receiving centre. Severely injured patients have shown better outcomes if treated in a major trauma centre (MTC). We aimed to evaluate patient distribution in the Dutch trauma system. Furthermore, we sought to identify factors associated with the undertriage and transport of severely injured patients (Injury Severity Score (ISS) >15) to the MTC by emergency medical services (EMS).Methods: Data on all acute trauma admissions in the Netherlands (2015-2016) were extracted from the Dutch national trauma registry. An ambulance driving time model was applied to calculate MTC transport times and transport times of ISS >15 patients to the closest MTC and non-MTC. A multivariable logistic regression analysis was performed to identify factors associated with ISS >15 patients' EMS undertriage to an MTC.Results: Of the annual average of 78,123 acute trauma admissions, 4.9% had an ISS >15. The nonseverely injured patients were predominantly treated at non-MTCs (79.2%), and 65.4% of patients with an ISS >15 received primary MTC care. This rate varied across the eleven Dutch trauma networks (36.8%-88.4%) and was correlated with the transport times to an MTC (Pearson correlation -0.753, p=0.007). The trauma networks also differed in the rates of secondary transfers of ISS >15 patients to MTC hospitals (7.8% 59.3%) and definitive MTC care (43.6% - 93.2%). Factors associated with EMS undertriage of ISS >15 patients to the MTC were female sex, older age, severe thoracic and abdominal injury, and longer additional EMS transport times.Conclusions: Approximately one-third of all severely injured patients in the Netherlands are not initially treated at an MTC. Special attention needs to be directed to identifying patient groups with a high risk of undertriage. Furthermore, resources to overcome longer transport times to an MTC, including the availability of ambulance and helicopter services, may improve direct MTC care and result in a decrease in the variation of the undertriage of severely injured patients to MTCs among the Dutch trauma networks. Furthermore, attention needs to be directed to improving primary triage guidelines and instituting uniform interfacility transfer agreements. (C) 2021 Elsevier Ltd. All rights reserved.Trauma Surger