Master of Science / Department of Industrial & Manufacturing Systems Engineering / Malgorzata J. Rys / Emergency Medical Systems (EMS) are designed to handle emergencies. Fortunately, most emergencies faced have only one patient. The every day system is not designed to respond to emergencies in which there are many casualties. Due to natural disasters and terrorist attacks that have occurred over the past decade, mass-casualty disaster response plans have become a priority for many organizations, including EMS. The resources available for constructing such plans are limited. Physical simulations or practices of the plan are often performed; however, it is not until a disaster strikes that the capabilities of the plan are truly realized. In this paper, it is proposed that discrete-event simulations are used as part of the planning process. A computer simulation can test the capability of the plan under different settings and help planners in their decision making. This paper looks at the creation of a discrete-event simulation using ARENA software. The simulation was found to accurately simulate the response to the Greensburg tornado that occurred May of 2008. A sensitivity analysis found that the simulation results are dependent upon the values assumed for Volunteer Injury Rate, Injury Level, Information Dissemination Rate and Transportation Decision variables. When a disaster occurs, the local resources are overwhelmed and outside aide must be called in. Decision rules for when to request more outside ambulances and when to release them to send them home are evaluated. The more resources that are made available, the quicker patients receive medical care. However, when outside ambulances are called in, they are putting their home area at risk because it no longer has complete (or any) ambulance coverage. As the percent of coverage decreases, the amount of time that victims spend waiting for ambulances also decreases. Many decision rules were evaluated, resulting in various combinations of ambulance wait times and average percent coverage. It is up to Disaster Planners to determine how much of an additional wait can be assumed by the disaster victims to prevent outside districts from taking on unwarranted risk of low coverage.

Master of Science / Department of Industrial & Manufacturing Systems Engineering / Malgorzata J. Rys / Emergency department (ED) overcrowding is a nationwide problem affecting the safety and preparedness of our health care system. Many hospital EDs face significant short and intense surges in demand on a daily basis. However, the surge in demand during disaster event is not short and intense, but it is a sustained one. In order to meet this sudden surge as defined above, hospital EDs need to be more prepared and efficient to cater to increased volume of demand involving huge uncertainties. This thesis looks at the creation and use of discrete event simulation modeling using ARENA 10.0 software. In this thesis, an attempt is made to show how the different arrival patterns and time durations for which victims keep arriving affect the EDs ability to treat the patients. It is shown, how the model can be used to estimate additional resources that would be required to accommodate additional patients within the ED. Various shapes of arrival distributions were tested for different time durations. It was found that the arrival distribution with parameters (3, 4), (3, 3), (4, 2) and (2, 4) did not challenge the institutional capacity. In other words, the hospital was able to treat all the patients without compromising the quality of care up to 24 hours. However, distribution with parameter (3, 2), (2, 2), (3, 1), (1, 2), (2, 3), (2, 1), (1, 4), (1, 3), (1, 1) and (0.5, 2) did affect the system performance. Under these distributions, there was at least one patient who was either dead, LWBS or diverted. This indicates the immediacy with which victims arriving under these distributions overwhelmed the limited resources Our aim was to study, how many more resources would the ED need in order to have zero critical expire, zero Left without Being Seen (LWBS) and zero patients diverted. Arrival distribution (1, 2) was randomly selected to study this objective and it was found that for a 24 hours of simulation run time, an additional of two full trauma resources were required in order to have zero critical expire in trauma rooms area and additional of five ED beds and three nurses were required in treatment area for patients with moderate severity to have zero LWBS. With these additional resources, the ED was also able to treat all the non disaster related patients thereby having zero patients diverted. The same procedure can be used to determine the number of additional resources ED would require to treat all the victims arriving with the rest of the arrival distribution for different time periods. The simulation model built would help the emergency planners to better allocate and utilize the limited ED resources in order to treat maximum possible patients. It also helps estimate the number of additional resources that would be required in a particular scenario.

Doctor of Philosophy / Department of Geography / Bimal K. Paul / Medical tourism comprises a phenomenon where over five million patients a year are traveling across international borders to obtain various forms of health care. Most of these patients travel from developed countries to developing countries, seeking highly invasive medical treatments to less invasive and recreational medical procedures. By the year 2012, the medical tourism industry generated over $100 billion with over 50 countries making it a priority in trade for their country. With active government promotions, India has become one of the leading destinations for medical tourism. The objective of this research was to answer the questions: 1) how do the attitudes and behaviors of patients towards the concept of medical tourism influence their decision to become a medical tourist; 2) why do medical tourists seek treatment in India; and 3) what are the issues and challenges they face before coming to India as well as while in India. Interviews of thirty-four foreign patients were conducted in six sites spread across the South-Indian cities of Bangalore, Hyderabad, and Chennai which revealed useful information in addressing the research objectives. The three most important reasons that these medical tourists chose India for their treatments were: 1) the high quality of the doctors and medical facilities in India, 2) the affordable cost of treatments, and 3) the availability of specific treatments that might not have been available in their home countries. Patients also researched the topic thoroughly before they came to India. Knowledge was gained primarily from the Internet, print media, television shows and friends. Overall, the patients had very positive attitudes towards medical tourism. Most of them felt that they could get treatment because of their positive opinion on medical tourism, their ability to get treatment if they desired, and support from their families and loved ones.

Hepatitis B virus (HBV) infection is a global leading cause of death as a result of its role in the development of cirrhosis, hepatic decompensation, and hepatocellular carcinoma (HCC). In industrialized nations such as the United States, chronic hepatitis B infection represents a significant and disproportionate disease burden among the foreign-born population. A Markov cohort decision model was developed to determine the cost-effectiveness of HBV screening among new immigrants for the purposes of early detection and treatment, as compared to usual care. The incremental cost-effectiveness ratio for the screening strategy was $45,570 per quality adjusted life year saved. Given the potential for health gains for the immigrant cohort as well as the economic attractiveness of the intervention, some consideration should be given to the addition of a universal HBV screening program to U.S. immigration policy.

Hepatitis B virus (HBV) infection is a global leading cause of death as a result of its role in the development of cirrhosis, hepatic decompensation, and hepatocellular carcinoma (HCC). In industrialized nations such as the United States, chronic hepatitis B infection represents a significant and disproportionate disease burden among the foreign-born population. A Markov cohort decision model was developed to determine the cost-effectiveness of HBV screening among new immigrants for the purposes of early detection and treatment, as compared to usual care. The incremental cost-effectiveness ratio for the screening strategy was $45,570 per quality adjusted life year saved. Given the potential for health gains for the immigrant cohort as well as the economic attractiveness of the intervention, some consideration should be given to the addition of a universal HBV screening program to U.S. immigration policy.

Doctor of Philosophy / Department of Industrial & Manufacturing Systems Engineering / David H. Ben-Arieh / Chih-Hang Wu / Patients who suffer from sepsis or septic shock are of great concern in the healthcare system. Recent data indicate that more than 900,000 severe sepsis or septic shock cases developed in the United States with mortality rates between 20% and 80%. In the United States alone, almost $17 billion is spent each year for the treatment of patients with sepsis. Clinical trials of treatments for sepsis have been extensively studied in the last 30 years, but there is no general agreement of the effectiveness of the proposed treatments for sepsis. Therefore, it is necessary to find accurate and effective tools that can help physicians predict the progression of disease in a patient-specific way, and then provide physicians recommendation on the treatment of sepsis to lower risk for patients dying from sepsis. The goal of this research is to develop a risk assessment tool and a risk management tool for sepsis. In order to achieve this goal, two system dynamic mathematical models (SDMMs) are initially developed to predict dynamic patterns of sepsis progression in innate immunity and adaptive immunity. The two SDMMs are able to identify key indicators and key processes of inflammatory responses to an infection, and a sepsis progression. Second, an integrated-mathematical-multi-agent-based model (IMMABM) is developed to capture the stochastic nature embedded in the development of inflammatory responses to a sepsis. Unlike existing agent-based models, this agent-based model is enhanced by incorporating developed SDMMs and extensive experimental data. With the risk assessment tools, a Markov decision process (MDP) is proposed, as a risk management tool, to apply to clinical decision-makings on sepsis. With extensive computational studies, the major contributions of this research are to firstly develop risk assessment tools to identify the risk of sepsis development during the immune system responding to an infection, and secondly propose a decision-making framework to manage the risk of infected individuals dying from sepsis. The methodology and modeling framework used in this dissertation can be expanded to other disease situations and treatment applications, and have a broad impact to the research area related to computational modeling, biology, medical decision-making, and industrial engineering.

We first studied factors associated with the rate of colonoscopy by primary care physicians (PCPs) in Ontario between the years 1996 and 2005. Next, we conducted an Instrumental Variable Analysis (IVA) to estimate the effect of colonoscopy on colorectal cancer (CRC) incidence and mortality on average-risk subjects aged 50-74 years. Finally, we explored two study cohorts, one by including subjects who had the outcomes during the exposure period (unselected cohort) and the other cohort by excluding those subjects (restricted cohort). We estimated the absolute risk reduction associated with colonoscopy in preventing CRC incidence and mortality using traditional regression analysis, propensity score analysis and IVA. PCPs who were Canadian medical graduates and with more years of experience were more likely to use colonoscopy. PCPs were more likely to use colonoscopy if their patient populations were predominantly women, older, had more illnesses, and if their patients resided in less marginalized neighborhoods (lower unemployment, fewer immigrants, higher income, higher education, and higher English/French fluency). Using PCP rate of discretionary colonoscopy as an instrumental variable, receipt of colonoscopy was associated with a 0.60% absolute reduction in 7-year CRC incidence and a 0.17% absolute reduction in 5-year risk of death due to CRC. The unselected cohort showed an increase in CRC incidence and mortality associated with colonoscopy, whereas the restricted cohort showed a reduction in CRC incidence and mortality associated with colonoscopy. In the restricted cohort, using different statistical models, the absolute risk reduction varied from 0.52-0.60% for CRC incidence and 0.08-0.17% for CRC mortality. There were social disparities in the use of colonoscopy by PCPs and this disparity increased as the overall use of colonoscopy increased over time. Colonoscopy is effective in reducing incidence and mortality due to CRC. Different methods of subject selection and statistical analysis provided different estimates of colonoscopy effectiveness.

We first studied factors associated with the rate of colonoscopy by primary care physicians (PCPs) in Ontario between the years 1996 and 2005. Next, we conducted an Instrumental Variable Analysis (IVA) to estimate the effect of colonoscopy on colorectal cancer (CRC) incidence and mortality on average-risk subjects aged 50-74 years. Finally, we explored two study cohorts, one by including subjects who had the outcomes during the exposure period (unselected cohort) and the other cohort by excluding those subjects (restricted cohort). We estimated the absolute risk reduction associated with colonoscopy in preventing CRC incidence and mortality using traditional regression analysis, propensity score analysis and IVA. PCPs who were Canadian medical graduates and with more years of experience were more likely to use colonoscopy. PCPs were more likely to use colonoscopy if their patient populations were predominantly women, older, had more illnesses, and if their patients resided in less marginalized neighborhoods (lower unemployment, fewer immigrants, higher income, higher education, and higher English/French fluency). Using PCP rate of discretionary colonoscopy as an instrumental variable, receipt of colonoscopy was associated with a 0.60% absolute reduction in 7-year CRC incidence and a 0.17% absolute reduction in 5-year risk of death due to CRC. The unselected cohort showed an increase in CRC incidence and mortality associated with colonoscopy, whereas the restricted cohort showed a reduction in CRC incidence and mortality associated with colonoscopy. In the restricted cohort, using different statistical models, the absolute risk reduction varied from 0.52-0.60% for CRC incidence and 0.08-0.17% for CRC mortality. There were social disparities in the use of colonoscopy by PCPs and this disparity increased as the overall use of colonoscopy increased over time. Colonoscopy is effective in reducing incidence and mortality due to CRC. Different methods of subject selection and statistical analysis provided different estimates of colonoscopy effectiveness.

Master of Science / Department of Kinesiology / Timothy I. Musch / Aged rats exhibit a decreased muscle microvascular O[subscript]2 partial pressure (PO[subcript]2mv) at rest as well as during contractions compared to young rats and this may contribute to their reduced exercise tolerance. Age-related reductions in nitric oxide (NO) bioavailability due, in part, to elevated reactive O[subscript]2 species (ROS) constrain muscle blood flow (Qm). Therefore, antioxidants may restore NO bioavailability, Qm and ameliorate the reduction in PO[subscript]2mv and hence the decrease in exercise tolerance seen in aged rats. PURPOSE: To test the hypothesis that antioxidants would elevate Qm at rest and during contractions and therefore PO[subscript]2mv in aged muscle. METHODS: PO[subscript]2mv and Qm were measured in the spinotrapezius while muscle oxygen consumption (VO[subscript]2m) was estimated in 20 anesthetized male Fisher 344 x Brown Norway hybrid (F344xBN) rats at rest and during 1 Hz contractions before and after antioxidant intravenous infusion (76mg/kg vitamin C and 52mg/kg tempol). Moreover, muscle force production was measured in a subset of animals. RESULTS: Before infusion, contractions invoked a biphasic PO[subscript]2mv that fell from 30.6 [plus or minus] 0.9 mmHg to a nadir of 16.8 [plus or minus] 1.2 mmHg with an 'undershoot' of 2.8 [plus or minus] 0.7 mmHg below the subsequent steady-state (19.7 [plus or minus] 1.2 mmHg). Antioxidants elevated baseline PO[subscript]2mv to 35.7 [plus or minus] 0.8 mmHg (P<0.05) and reduced or abolished the 'undershoot' (P<0.05) without changing the steady-state contracting PO[plus or minus]2mv. Antioxidants did not change Qm at rest but during contractions Qm was reduced from 157 [plus or minus] 28 to 91 [plus or minus] 15 ml min[superscript]-1 100g[superscript]-1 (P<0.05). Antioxidants produced no significant effect on VO[subscript]2m. However, antioxidant supplementation produced a 16.5% decrease (P<0.05) in muscle force production that occurred within the first contraction and remained throughout the duration of stimulation. In addition, the ratio of muscle force production to VO[subscript]2m (F/VO[subscript]2m) actually increased from 0.92 [plus or minus] 0.03 to 1.06 [plus or minus] 0.6 (P<0.05) following infusion of antioxidants. CONCLUSION: Antioxidant supplementation significantly alters the balance between muscle O[subscript]2 delivery and VO[subscript]2 at rest and during contractions, which modifies the microvascular PO[subscript]2mv profile. Specifically, antioxidants elevate PO[subscript]2mv, which improves the potential for diffusive blood-myocyte flux. This effect arises, in part, from the unanticipated fall in muscle force production consequent to antioxidant supplementation.

Doctor of Philosophy / Department of Hospitality Management and Dietetics / Deborah D. Canter / The culture-change movement in skilled nursing facilities is challenging foodservices to consider their role in supporting the paradigm shift to person-centered care. Optimal nutrition for residents supports physical and emotional health of institutionalized older adults. The purpose of this study was to explore factors associated with resident dining in skilled nursing facilities that have transitioned from a traditional foodservice system to restaurant-style dining. The study investigated foodservice employee perceptions of resident satisfaction with foodservices, foodservice employee job satisfaction, and effect of the delivery system transition on employee intent to leave. The study was conducted in two phases. Phase I was a case study of one skilled nursing facility’s transition from the traditional foodservice to restaurant-style dining. Phase II consisted of a survey of residents and employees in seven skilled nursing facilities utilizing restaurant-style dining. Two questionnaires, addressing the constructs of food quality, service quality, and customization relating to resident satisfaction with foodservices, were developed and administered to residents and foodservice employees. The Phase 1 case study revealed differences in financial and unintended weight loss data from pre- to post-menu transitioning. Focus groups provided insight into resident satisfaction with food and foodservices. In both phases, residents were satisfied with restaurant-style dining. Statements regarding the ability to choose foods at meals times scored highly. Service statements such as “Being treated respectfully by employees” were rated high by the residents. Portion sizes and food quality consistency were rated lower by residents. Employee perceptions of resident satisfaction were consistent with the resident ratings of satisfaction. Foodservice employee job satisfaction was high and intent to leave was low. Job satisfaction mediated the relationship between the employee perception of resident service and their intent to leave. Overall, restaurant-style dining appears to be a positive alternative to the traditional foodservice system in skilled nursing facilities. Implications and future research are discussed.