Christos Vasilakis

Christos Vasilakis
University of Bath | UB · Faculty of Management

PhD

About

110
Publications
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2,297
Citations

Publications

Publications (110)
Article
Full-text available
Purpose The purpose of this paper is to examine patient engagement in remote consultation services, an increasingly important issue facing Healthcare Operations Management (HOM) given the significant expansion in this and other forms of telehealth worldwide over the last decade. We use our analysis of the literature to develop a comprehensive frame...
Article
Full-text available
Throughout its history, Operational Research has evolved to include a variety of methods, models and algorithms that have been applied to a diverse and wide range of contexts. This encyclopedic article consists of two main sections: methods and applications. The first aims to summarise the up-to-date knowledge and provide an overview of the state-o...
Article
Background The National Health Service (NHS) Talking Therapies program treats people with common mental health problems in England according to “stepped care,” in which lower-intensity interventions are offered in the first instance, where clinically appropriate. Limited resources and pressure to achieve service standards mean that program provider...
Preprint
BACKGROUND The National Health Service (NHS) Talking Therapies program treats people with common mental health problems in England according to “stepped care,” in which lower-intensity interventions are offered in the first instance, where clinically appropriate. Limited resources and pressure to achieve service standards mean that program provider...
Preprint
Full-text available
Throughout its history, Operational Research has evolved to include a variety of methods, models and algorithms that have been applied to a diverse and wide range of contexts. This encyclopedic article consists of two main sections: methods and applications. The first aims to summarise the up-to-date knowledge and provide an overview of the state-o...
Article
Full-text available
Background It is a stated ambition of many healthcare systems to eliminate delayed transfers of care (DTOCs) between acute and step-down community services.Objective This study aims to demonstrate how, counter to intuition, pursual of such a policy is likely to be uneconomical, as it would require large amounts of community capacity to accommodate...
Article
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Background Optimising capacity along clinical pathways is essential to avoid severe hospital pressure and help ensure best patient outcomes and financial sustainability. Yet, typical approaches, using only average arrival rate and average lengths of stay, are known to underestimate the number of beds required. This study investigates the extent to...
Article
Background: Transferring individuals for treatment outside their geographic area occurs when healthcare demand exceeds local supply. This can result in significant financial cost while impacting patient outcomes and experience. Aims: The aim of this study was to assess initiatives to reduce psychiatric intensive care unit (PICU) out-of-area bed...
Article
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Objectives While there has been significant research on the pressures facing acute hospitals during the COVID-19 pandemic, there has been less interest in downstream community services which have also been challenged in meeting demand. This study aimed to estimate the theoretical cost-optimal capacity requirement for ‘step down’ intermediate care s...
Article
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Despite the many examples where simulation has successfully demonstrated its capability in modelling patient flow, there is little evidence of enduring widespread use. Bespoke academic projects provide little scope for repeatable practical application and efforts to develop generic reusable solutions have neither clearly identified the end users no...
Article
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Although many emergency hospital admissions may be unavoidable, a proportion of these admissions represent a failure of the care system. The adverse consequences of avoidable emergency hospital admissions affect patients, carers, care systems and substantially increase care costs. The aim of this study was to develop and validate a risk prediction...
Article
Background Anesthesiologists integrate numerous variables to determine an opioid dose that manages patient nociception and pain while minimizing adverse effects. Clinical dashboards that enable physicians to compare themselves to their peers can reduce unnecessary variation in patient care and improve outcomes. However, due to the complexity of ane...
Article
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Background Billions of doses of medicines are donated for mass drug administrations in support of the World Health Organization’s “Roadmap to Implementation,” which aims to control, eliminate, and eradicate Neglected Tropical Diseases (NTDs). The supply chain to deliver these medicines is complex, with fragmented data systems and limited visibility...
Article
Demographic changes, particularly population ageing, and rising morbidity from chronic conditions contribute to ever-increasing pressures on health and care systems in developed countries. Partly as a response, new models of care and service innovations are being piloted and introduced. However, the effectiveness and sustainability of these complex...
Preprint
Full-text available
Objectives: While there has been significant research on the pressures facing acute hospitals during the COVID-19 pandemic, there has been less interest in downstream community services which have also been challenged in meeting demand. This study aimed to estimate the theoretical cost-optimal capacity requirement for 'step down' intermediate care...
Article
Objective To develop and scale algorithm-enabled patient prioritization to improve population-level management of type 1 diabetes (T1D) in a pediatric clinic with fixed resources, using telemedicine and remote monitoring of patients via continuous glucose monitor (CGM) data review. Research Design and Methods We adapted consensus glucose targets f...
Preprint
Full-text available
Background Billions of doses of medicines are donated for mass drug administrations in support of the World Health Organization’s “Roadmap to Implementation,” which aims to control, eliminate, and eradicate Neglected Tropical Diseases (NTDs). The supply chain to deliver these medicines is complex, with fragmented data systems and limited visibility...
Preprint
Full-text available
Objective: To develop and scale algorithm-enabled patient prioritization to improve population-level management of type 1 diabetes (T1D) in a pediatric clinic with fixed resources, using telemedicine and remote monitoring of patients via continuous glucose monitor (CGM) data review. Research Design and Methods: We adapted consensus glucose targets...
Article
In response to societal restrictions due to the COVID‐19 pandemic, a significant proportion of physical outpatient consultations were replaced with virtual appointments within the Bristol, North Somerset and South Gloucestershire healthcare system. The objective of this study was to assess the impact of this change in informing the potential viabil...
Article
Full-text available
Background The study sought to evaluate the impact of a Rapid Diagnostic Clinic (RDC) service designed to improve general practitioner (GP) referral processes for patients who do not meet existing referral criteria yet present with vague - but potentially concerning - symptoms of cancer. We sought to investigate how well the RDC has performed in th...
Article
Aim: Identify, simulate, and evaluate the formal and informal patient-level and unit-level factors that nurse managers use to determine the number of nurses for each shift. Background: Nurse staffing schedules are commonly set based on metrics such as midnight census that do not account for seasonality or midday turnover, resulting in last-minut...
Preprint
Full-text available
Mass vaccination is widely considered to offer the only route out of the COVID-19 pandemic in a way that social restrictions can be eased and economic activity can safely resume without compromising healthcare services. For many countries, dedicated vaccination centres are a key part of that effort. However, with no directly comparable historical e...
Article
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Background: During the COVID-19 pandemic, many intensive care units have been overwhelmed by unprecedented levels of demand. Notwithstanding ethical considerations, the prioritization of patients with better prognoses may support a more effective use of available capacity in maximizing aggregate outcomes. This has prompted various proposed triage...
Article
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Managing healthcare demand and capacity is especially difficult in the context of the COVID-19 pandemic, where limited intensive care resources can be overwhelmed by a large number of cases requiring admission in a short space of time. If patients are unable to access this specialist resource, then death is a likely outcome. In appreciating these ‘...
Article
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Purpose The purpose of this study had two aims: (1) to extend insight regarding the challenges of implementing standardised work, via care pathways, in a healthcare setting by considering interactions with other operational (i.e. resource sharing, portfolio alignment) and professional (i.e. autonomous expertise) dependencies and (2) to develop nove...
Preprint
Full-text available
Background Managing healthcare demand and capacity is especially difficult in the context of the COVID-19 pandemic, where limited intensive care resources can be overwhelmed by a large number of cases requiring admission in a short space of time. If patients are unable to access this specialist resource, then death is a likely outcome. The aim of t...
Article
Full-text available
Introduction Massive open online courses (MOOCs) offer a flexible approach to online and distance learning, and are growing in popularity. Several MOOCs are now available, to help learners build on their knowledge in a number of healthcare topics. More research is needed to determine the effectiveness of MOOCs as an online education tool, and explo...
Article
This paper introduces FLP Spreadsheet Solver, an open source spreadsheet based Decision Support System for Facility Location Problems. Structure of the spreadsheets, interface of the solver, and a Tabu Search algorithm implemented within the solver are described. An integer programming formulation of the underlying facility location problem is prov...
Article
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Background Standardised tobacco packaging has been, and remains, a contentious policy globally, attracting corporate, public health, political, media and popular attention. In January 2015, the UK Government announced it would vote on draft regulations for the policy before the May 2015 General Election. We explored reactions to the announcement on...
Article
Timely and adequate provision of blood following mass casualty events (MCEs) is critical to reducing mortality rates amongst casualties transported to hospital following an event. Developing planning strategies to ensure the blood transfusion demands of casualties are met is challenging. Discrete event simulation (DES) offers a novel solution to th...
Article
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The development and implementation of innovation by healthcare providers is understood as a multi-determinant and multi-level process. Theories at different analytical levels (i.e. micro and organisational) are needed to capture the processes that influence innovation by provide. This article combines a micro theory of innovation, actor-network the...
Article
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Objectives Overcrowding in the emergency department (ED) is common in the UK as in other countries worldwide. Computer simulation is one approach used for understanding the causes of ED overcrowding and assessing the likely impact of changes to the delivery of emergency care. However, little is known about the usefulness of computer simulation for...
Article
Full-text available
Objective To explore the quality and safety of patients’ healthcare provision by identifying whether being a medical outlier is associated with worse patient outcomes. A medical outlier is a hospital inpatient who is classified as a medical patient for an episode within a spell of care and has at least one non-medical ward placement within that spe...
Article
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Background The number of people affected by Parkinson’s disease (PD) is increasing in the United Kingdom driven by population ageing. The treatment of the disease is complex, resource intensive and currently there is no known cure to PD. The National Health Service (NHS), the public organisation delivering healthcare in the UK, is under financial p...
Article
Background: Traumatic hemorrhage is a leading preventable cause of mortality following mass casualty events (MCEs). Improving outcomes requires adequate in-hospital provision of high volume red blood cell (RBC) transfusions. This study investigated strategies for optimizing RBC provision to casualties in MCEs using simulation modeling. Methods:...
Article
Introduction: Mass casualty events (MCEs) generate a surge in severely injured bleeding casualties requiring rapid resuscitation primarily through high volume red blood cell (RBC) transfusion to maintain end organ perfusion. The significant RBC demand of these events threatens to overwhelm in-hospital RBC supplies. We investigated transfusion base...
Article
The ever increasing pressures to ensure the most efficient and effective use of limited health service resources will, over time, encourage policy makers to turn to system modelling solutions. Such techniques have been available for decades, but despite ample research which demonstrates potential, their application in health services to date is lim...
Article
We describe a decision support toolkit that was developed with the aim of assisting those responsible with the management and treatment of Parkinson’s disease (PD) in the UK. Having created a baseline model and established its face validity, the toolkit captures the complexity of PD services at a sufficient level and operates within a user-friendly...
Article
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Changes in medical practice, demographic shifts and financial pressures are all examples of factors that may contribute to demand for periodic changes in the configuration of health services. When reconfiguring a service, health planners often take into account projected demand for services, patient access criteria and budgetary constraints (among...
Article
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Health and social care systems are facing major challenges worldwide, due in part to changes in demography and advances in technology and in part to changes in the structure and organisation of care delivery. The IMA Health 2013 conference brought together health care managers, clinicians, management consultants, and mathematicians, operational and...
Article
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Eye is the official journal of the Royal College of Ophthalmologists. It aims to provide the practising ophthalmologist with information on the latest clinical and laboratory-based research.
Article
The aim of this study was to develop a framework that would support the evaluation of new ways of diagnosing and monitoring chronic eye disease being planned and implemented by a large NHS hospital. The study involved interviews with a range of health care professionals within the Trust, observation of glaucoma outpatient clinics and related meetin...
Article
Full-text available
Obesity care services are often faced with the need to adapt their resources to rising levels of demand. The main focus of this study was to help prioritise planned investments in new capacity allowing the service to improve patient experience and meet future anticipated demand. We developed computer models of patient flows in an obesity service in...
Article
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Existing approaches to conceptual modelling (CM) in discrete-event simulation do not formally support the participation of a group of stakeholders. Simulation in healthcare can benefit from stakeholder participation as it makes possible to share multiple views and tacit knowledge from different parts of the system. We put forward a framework tailor...
Article
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We describe a modelling toolkit that was developed with the aim of assisting those responsible for introducing stepped care systems to local mental health services in the UK. The toolkit was pre-populated with real patient flow data collected from four sites that piloted the stepped care system design. Two analytical models were developed and coded...
Article
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This paper uses a case study of a multidisciplinary colorectal cancer team in health care to explain how a model of performance measures can lead to debate and action in Soft System Methodology (SSM). This study gives a greater emphasis and role to the performance measures than currently given in typical SSM studies. Currently, the concept of perfo...
Article
Background: Liver resection for metastatic colorectal cancer became established without randomized trials. Proponents of surgical resection point out 5-year survival approaching 50% whilst critics question how much of the apparent effect is due to patient selection. Method: A 2006 systematic review of reported outcomes provided the starting poin...
Article
It is possible to prolong the life of some paediatric patients awaiting heart transplantation using ‘bridging’ technology, which involves admission to an intensive care environment. It is expected that such bridging reduces deaths on the waiting list and increases the utilization of donor organs. However, bridging offers no guarantee of survival to...
Article
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The Institute of Mathematics and its Applications has been organising the IMA International Conference on Quantitative Modelling in the Management of Health Care since 1995. The aim of the conference is to bring together health care managers, clinicians, management consultants, and mathematicians, operational researchers, statisticians, economists...
Article
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In the United Kingdom, clinical guidelines recommend that services for depression and anxiety should be structured around a stepped care model, where patients receive treatment at different 'steps,' with the intensity of treatment (i.e., the amount and type) increasing at each step if they fail to benefit at previous steps. There are very limited d...
Article
Full-text available
The Institute of Mathematics and its Applications has been organising the IMA International Conference on Quantitative Modelling in the Management of Health Care since 1995. The aim of the conference is to bring together health care managers, clinicians, management consultants, and mathematicians, operational researchers, statisticians, economists...
Article
Full-text available
Patient adherence to medication, defined as the extent to which patients take medications as prescribed, can determine the effectiveness of a pharmaceutical therapy. In the management of chronic disease in particular, it is known that improved adherence could generate significant health and economic gains. However, understanding the potential conse...
Article
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We describe a software tool specifically developed to support the monitoring and reporting of the occurrence of surgical site infections (SSI) in hospitals. The tool uses data collected routinely by a London teaching hospital as part of its infection surveillance system, which includes post-discharge follow-up. Based on these data, the tool is used...
Article
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Pulmonary metastasectomy for colorectal cancer is a commonly performed and well-established practice of ∼50 years standing. However, there have been no controlled studies, randomised or otherwise. We sought to investigate the evidence base that has been used in establishing its status as a standard of care. Among 51 papers used in a recent systemat...
Article
Computer simulation has been employed to evaluate proposed changes in the delivery of health care. However, little is known about the utility of simulation approaches for analysis of changes in the delivery of surgical care. We searched eight bibliographic databases for this comprehensive review of the literature published over the past five decade...
Article
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We present the findings of a discrete event simulation study of the hospital pharmacy outpatient dispensing systems at two London hospitals. Having created a model and established its face validity, we tested scenarios to estimate the likely impact of changes in prescription workload, staffing levels and skill-mix, and utilisation of the dispensari...
Conference Paper
Full-text available
Conceptual modelling, one of the first stages in a simulation study, is about understanding the situation under study and deciding what and how to model. We argue that stakeholder involvement as part of conceptual modelling could lead to a more successful simulation study with better prospects for implementation. Our work is mainly applied in healt...
Chapter
The unified modelling language (UML) comprises a set of tools for documenting the analysis of a system. Although UML is generally used to describe and evaluate the functioning of complex systems, the extent of its application to the health care domain is unknown. The purpose of this article is to survey the literature on the application of UML tool...
Article
Full-text available
The Unified Modelling Language (UML) comprises a set of tools for documenting the analysis of a system. Although UML is generally used to describe and evaluate the functioning of complex systems, the extend of its application to the health care domain is unknown. The purpose of this paper is to survey the literature on the application of UML tools...