Healthcare organizations are often stymied in their efforts to prevent insider attacks that violate patient privacy. Numerous high-profile privacy breaches involving celebrities have brought this deficiency to the public's attention. In response, recent legislation aims to improve this situation by means of regulations and sanctions. While the public and government may demand more privacy safeguards, the current state-of-the-art tools in healthcare security, such as access control and auditing, will still be limited in their ability to solve the issue technically. These technologies are theoretically sound and tested in other industries, yet are suboptimal because no feasible methods exist for generating the policies these systems must act upon, due to the inherent complexities of modern healthcare organizations. To address this shortcoming, we present a novel open-source framework, which mines low-level statistics of how users interact within the organization from the access logs of the organization's information systems. Our framework is scalablecapable of handling real world data integrity issues. We demonstrate the use of our tool by modeling the Vanderbilt University Medical Center. Additionally, we compare our framework's model to traditional experts who would attempt to manually generate a similar model.

Clinical decision support in electronic prescribing (e-Rx) systems can improve patient safety and quality of care. Despite the availability of drug information knowledgebases and decision support modules, users often disable this functionality or customize it to minimize irrelevant or insignificant alerts, due to concerns about alert fatigue, i.e., decreasing the "attention cost" of alerts. We postulate that novel user interfaces may decrease the "attention cost" of alerts, as has been shown in inpatient CPOE. This study explores alternative approaches to display alerts, and examines whether and how human factors based interface design can be used to improve signal detection from noisy data (alerts and reminders) in an existing e-Rx system. The issues in presenting multiple drug alerts in an outpatient e-Rx system are described. Several novel drug alert presentation interfaces are introduced. Both expert evaluation and formal usability testing show that the TreeDashboard-View is better perceived than the text-centric ScrollText-View in delivering multiple drug alerts during e-Rx practice. Physician prescribers' perceptions are discussed.

In health care, a widespread crisis of emergency department crowding has arisen from increasing patient demand and diminishing bed capacity. Predictable fluctuations in patient demand suggest that dynamic resource mobilization may allow for efficient, just-in-time allocation of personnel and beds; this strategy, however, would require a method to forecast near-future crowding. The dissertation presents techniques from queuing theory and discrete event simulation that enable accurate forecasting of emergency department operating conditions. A systematic review of the literature described the causes, effects, and solutions of emergency department crowding, revealing that several measures have been proposed to measure crowding, although none have been validated for the purpose of real-time forecasting. An independent, prospective validation of four previously published crowding measures indicated that three of them accurately discriminate present ambulance diversion, but none of them reliably forecast future ambulance diversion. A discrete event simulation, named ForecastED, was developed to mimic the process of patient flow through the emergency department, such that a single model could forecast many different outcome measures. A prospective evaluation of the ForecastED system demonstrated that the model provides reliable, real-time forecasts of seven different measures of crowding up to eight hours into the future. This technology may provide a foundation for health care providers to coordinate and avoid potentially dangerous crowding situations.

Living cells and tissues experience mechanical forces in their physiological environments that are known to affect many cellular processes. Also of importance are the mechanical properties of cells, as well as the microforces generated by cellular processes in their microenvironments. The difficulty associated with studying these phenomena in vivo has led to alternatives such as using in vitro models. The need for experimental techniques for investigating cellular biomechanics and mechanobiology in vitro has fueled an evolution in the technology used in these studies. Particularly noteworthy are some of the new biomicroelectromechanical systems (BioMEMs) devices and techniques. <p> This study describes cellular micromechanical techniques and methods that have been developed for extit{in vitro} studies. Improvements made to a passive array of vertical microcantilevers, for detecting cellular microforces and studying in vitro cell mechanics are presented. A new technique that uses poly(vinyl alcohol) (PVA) as a lift-off agent to attach structures to the microcantilevers, thereby providing a means to actively move the microcantilevers is introduced. The use of the improved microcantilever array platform as a potential assay for cardiac myofibrillogenesis will also be described. <p> Finally the use of cryogenic etching techniques for making master molds for the microcantilever arrays is described, and subsequent arrays are used to investigate the biological responses of mesenchymal stem cells to forces generated by post deflections.

Assessment of the restoration of load-bearing function is the central goal in the study of fracture healing process. During the fracture healing, two critical aspects affect its analysis: (1) material properties of the callus components, and (2) the spatio-temporal architecture of the callus with respect to cartilage and new bone formation. In this study, an inverse problem methodology is used which takes into account both features and yields material property estimates that can analyze the healing changes. Six stabilized fractured mouse tibias are obtained at two time points during the most active phase of the healing process, respectively 10 days (n=3), and 14 days (n=3) after fracture. Under the same displacement conditions, the inverse procedure estimations of the callus material properties are generated and compared to other fracture healing metrics. The FEA estimated property is the only metric shown to be statistically significant (p=0.0194) in detecting the changes in the stiffness that occur during the healing time points. In addition, simulation studies regarding sensitivity to initial guess and noise are presented, as well as the influence of callus architecture on the FEA estimated material property metric. The finite element model inverse analysis developed can be used to determine the effects of genetics or therapeutic manipulations on fracture healing in rodents.

The emergency room is a challenging place to practice medicine. Overcrowding, episodic care, and an interrupt driven environment are all factors contributing to medical errors in the ED . We performed a comprehensive literature review to determine the nature of these errors at time of discharge from the ED. We follow through with a retrospective electronic chart review focusing on potentially inappropriately written drugs in the elderly in the ED. We conclude by presenting an integrated web based patient discharge framework that we custom designed and recently implemented in the Vanderbilt Adult Emergency Department.

The concept of health information exchange (HIE) among organizations in the United States has evolved over the last 25 years, from early efforts to build Community Health Information Networks to recent collaborations in the form of Regional Health Information Organizations (RHIOs). Previous HIE research focused on organizational issues, technological challenges, and impact on healthcare utilization. The research study was set in the MidSouth eHealth Alliance (MSeHA), a RHIO in southwestern Tennessee that has exchanged health data since 2006. This research applied qualitative methods to evaluate the impact of the HIE system on workflow and information flow at MSeHA-participating sites. The study was conducted over a 9-month period at six emergency departments and nine ambulatory clinics. Data collection focused on use of the same HIE technology across widely varying clinical contexts and health information technology (HIT) infrastructures. The researcher observed use of HIE technology and healthcare workflow for 187 hours and conducted semi-structured interviews to confirm observation data. Research results include identification of HIE-related workflow patterns, reasons for HIE technology use, and outcomes of HIE use. The research contributes an understanding of real-world HIE technology usage patterns across organizations, proposes context-aware implementation strategies for HIE systems, and identifies the potential of HIE technology to help transform healthcare.

We present a multi-dye ratiometric method for the correction of optical artifacts and unequal illumination encountered by researchers that utilize complex microfluidic systems. Using a novel chemotaxis system that provides cells with passively generated chemoattractant gradients, we demonstrate that the currently utilized method of single-color epi-fluorescence is limited in its ability to characterize gradient formation in the presence of differing channel heights and in the proximity of micron-sized features. As future devices strive to mimic the microtopography of physiological environments, this deficit will become increasingly relevant. The presented multi-color methodology allows for the correction of standard wide-field images and, with the incorporation of laser scanning confocal microscopy, explores three-dimensionally resolved gradient analysis. Using a validated numerical model, we also analyze the potential distortion in gradient formation introduced by device microstructure and the very cells that the system is designed to examine. Our analysis has important implications for the sensitivity of microfabricated systems to cell loading density and channel aspect ratio. In conclusion, the imaging and modeling methodologies introduced in this work will provide complementary information for the rational design and validation of microfluidic devices with cell-sized features.

We demonstrate a flexible, tunable scheme for synthesizing multifunctional, ultrasmall superparamagnetic iron oxide nanoparticles (USPIOs) and its application to the area of magnetic relaxation switches. USPIO cores (10nm) were functionalized with a poly(propylene sulfide)-bl-poly(ethylene glycol) (PPS-PEG) copolymer, yielding ~40nm micelles. PPS-PEG-ssDNA conjugates and fluorophore-conjugated PPS-PEG are incorporated into the micelle synthesis process, yielding ssDNA-coated magnetofluorescent particles. To form magnetic relaxation switches, we generated USPIO populations that display complementary ssDNA sequences. Mixing of complementary USPIOs leads to clustering, resulting in a significant increase in R2 magnetic relaxation. Treatment of the DNA-crosslinked USPIO clusters with restriction enzymes specific for the crosslinking sequence results in an irreversible return of R2 relaxation to baseline levels. The constructs demonstrate their utility as nanoscale sensors of restriction enzyme activity. The presented functionalization scheme can be extended to the generation of biosensors for other sources of proteolytic activity, for diagnostics and imaging applications for cancer and atherosclerosis.

Within the last decade, magnetic resonance imaging (MRI) scanners with ultra-high magnetic field strengths of 7 Tesla and above have become available. While high magnetic fields provide theoretical improvements in the nuclear magnetic resonance signal-to-noise ratio (SNR) and in the blood-oxygenation-level dependent (BOLD) contrast used for functional brain imaging, they also introduce technical issues such as increased bulk magnetic susceptibility effects and increased physiological noise in human data. Acquiring MRI data with multiple receiver coils in parallel can alleviate some of these issues at a cost to SNR and BOLD sensitivity that depends on several experiment-specific factors. This work attempts to address some of the issues surrounding high field fMRI in the context of parallel imaging and suggests methods for realizing the theoretical benefits of functional MRI with high magnetic fields.