Thomas R Rohleder

• PhD, University of Minnesota
• Professor at Mayo Foundation for Medical Education and Research

While early warning scores (EWS) have the potential to identify physiological deterioration in an acute care setting, the implementation of EWS in clinical practice has yet to be fully realized. The primary aim of this study is to identify optimal patient-centered rapid response team (RRT) activation rules using electronic medical records (EMR)-der...

Parallel processing of regional anesthesia may improve operating room (OR) efficiency in patients undergoes upper extremity surgical procedures. The purpose of this paper is to evaluate whether performing regional anesthesia outside the OR in parallel increases total cases per day, improve efficiency and productivity. Data from all adult patients w...

Capacity management and scheduling decisions are important for managing an outpatient clinic in which multiple classes of patients are treated. After an appointment is scheduled, it can be rescheduled, cancelled, or a patient may not show-up on their appointment day. This study simulates the behavior of patients with regard to the time to appointme...

Purpose: The purpose of our research is to develop patient-centered optimal resuscitation policies using electronic medical records (EMR). We seek to optimize care providers’ resuscitation decisions prior to and during acute physiological deterioration which is identified by abnormality or clinical decline in physiological measures. Method: W...

We used the systems engineering technique of discrete event simulation modeling to assist in increasing patient access to positron emission tomographic examinations in the Department of Nuclear Medicine at Mayo Clinic, Rochester. The model was used to determine the best universal slot length to address the specific access challenges of a destinatio...

Purpose: Transfer of intensive care unit (ICU) patients to the operating room (OR) is a resource-intensive, time-consuming process that often results in patient throughput inefficiencies, deficiencies in information transfer, and suboptimal nurse to patient ratios. This study evaluates the implementation of a coordinated patient transport system (...

The new Accreditation Council for Graduate Medical Education (ACGME) duty-hour standards for residents and fellows went into effect in 2011. These regulations were designed to reduce fatigue-related medical errors and improve patient safety. The new shift restrictions, however, have led to more frequent transitions in patient care (handoffs), resul...

In this article, we report on the implementation of a computerized scheduling tool to optimize staffing for patient transport at the Mayo Clinic. The tool was developed and implemented in Microsoft Excel and Visual Basic for Applications and includes an easy-to-use interface. The tool allows transport management to consider the trade-offs between p...

Recovery beds for cardiovascular surgical patients in the intensive care unit (ICU) and progressive care unit (PCU) are costly hospital resources that require effective management. This case study reports on the development and use of a discrete-event simulation model used to predict minimum bed needs to achieve the high patient service level deman...

The cardiovascular (CV) surgery department at Mayo Clinic is planning recovery bed (ICU and step down) needs for the next 10 years. While the current practice focuses on high service level (60% ICU utilization level), e.g., zero surgery cancelation, no shared rooms and no early discharges due to overloading; expected increasing patient volumes will...

Objective : Practice analysis of cardiac surgical service lines suggested that, for patients having routine cardiac surgery, standardization of care processes in the ICU could reduce cost and improve outcomes. We tested this hypothesis in a large surgical practice. Methods : Patients eligible for a standardized care pathway were prospectively ident...

In August 2010, the Third Annual Mayo Clinic Conference on Systems Engineering and Operations Research in Health Care was held. The continuing mission of the conference is to gather a multidisciplinary group of systems engineers, clinicians, administrators, and academic professors to discuss the translation of systems engineering methods to more ef...

At Mayo Clinic, care teams are being evaluated as a means to improve health care staff productivity and patient service. Traditional care in outpatient practices has health care staff working independently of each other with little coordination. Initial feedback by participating practices support the value of care teams. Our research focuses on a q...

We report on the use of discrete event simulation modeling to support process improvements at an orthopedic outpatient clinic. The clinic was effective in treating patients, but waiting time and congestion in the clinic created patient dissatisfaction and staff morale issues. The modeling helped to identify improvement alternatives including optimi...

Purpose The purpose of this paper is to report on the development of a qualitative systems model developed to understand why average emergency department (ED) length of stay (LOS) was rapidly increasing while the number of ED visits was relatively constant. The paper's focus was to identify systemic causes for poor patient flow so that the model co...

The early/tardy problem is one of the most vexing pieces of the complex production scheduling decision process. So far most of the research has been on single-machine environments. Hence, we considered the weighted early/tardy scheduling problem in a simulated dynamic multimachine job shop. We analyzed controlled job-release and dispatch rules usin...

We explain deviations away from the usual estimate of the expected number of false alarms per unit time in the use of a Statistical Process Control (SPC) chart. Using applied probability we develop an exact analytic expression for the expected number of false alarms per unit time. The derivation involves determining the expected value of a modulus...

In the past, performance in dynamic-scheduling environments was primarily measured in terms of time or physical shop characteristics. Objectives such as mean tardiness, flow time, and work-in-process inventory were commonly used. Today, there is increasing interest in the use of more advanced economic performance measures. These measures have the m...

We report on the use of simulation modeling for redesigning phlebotomy and specimen collection centers (or patient service centers) at a medical diagnostic laboratory. Research was performed in an effort to improve patient service, in particular to reduce average waiting times as well as their variability. Discrete-event simulation modeling provide...

Alberta, Canada is going through a period of unprecedented demand for health services, driven by the Province's growth. Problems arising from population growth have led to a gradual realization among health region planners that better tools are needed to help make policy decisions. We discuss our progress to date in introducing systems thinking and...

Many disasters have occurred because organizations have ignored the warning signs of precursor incidents or have failed to learn from the lessons of the past. Normal accident theory suggests that disasters are the unwanted, but inevitable output of complex socio-technical systems, while high-reliability theory sees disasters as preventable by certa...

Managing production and inventory for large-scale continuous processing plants is a key to success in the chemical process industry, particularly in the production of commodity polymers such as polyethylene and polypropylene. When setting up a production schedule, planners must consider the effects of off-grade production and production rate penalt...

Time waiting for service is a major concern for consumers, and excessive waiting for a pre-scheduled appointment is especially annoying. This is an on-going problem because appointment scheduling is a challenging task, mainly due to the uncertainties associated with service times. Prior studies have focused mainly on a single scheduling period (i.e...

We extend past research on the economic lot scheduling problem to address some of the limitations of the earlier work. In particular we develop mixed integer programming formulations with the assumption of a production precedence sequence. When evaluated over a variety of problems from the literature, it is clear that finding a schedule that minimi...

Health-care consumers continue to be frustrated with long waits, especially when an appointment has been made. However, providers who book appointments are under increasing pressure to maximize utilization so that revenues will be increased and costs reduced. Thus, scheduling appointments involves opposing forces that are difficult to manage. This...

We develop a method for finding the economic sampling plan that minimizes expected total costs, subject to a constraint on labour time. We explicitly recognize the labour time required for sampling, investigation, extra processing effort per unit due to operating the process out of control, and the time to put the process back into control. These t...

Service managers are continually challenged with balancing customer demand and service capacity. Recent studies have raised awareness of various demand and capacity management practices available to services, but little numerical work has been done to identify how these decisions work together and how they relate to one another. For instance, reduc...

This study considers whether consumers' motives to avoid waiting can be used to benefit both themselves and the services they attend. Specifically, two related aspects are explored: informing customers about alternative service delivery options that will allow them to avoid physically standing in line, and telling them at which times and days the s...

Although profitability is generally increased when services do well at matching demand and capacity, service managers continue to struggle in this area. This article summarises major demand and capacity management literature from both operations and marketing fields with the view to combine the knowledge into a pragmatically based framework. The pr...

Clients of services expect short waiting times and servers desire short periods of non-productive time. One of the areas where this is most important is appointment scheduling systems. Recent research has indicated that using information about clients’ service time variability can simultaneously reduce waiting times and server idle time. In this st...

Consider an organization whose capability to produce an item and whose customer demand are both stochastic. In such a context “take-or-pay” contracts can be attractive. Under such a contract the organization agrees to purchase from a supplier a fixed quantity per period over a specified number of periods. Simulation is too slow an analysis approach...

Abstract In this paper we consider the use of an,- chart for controlling a single-stage process. X The three controllable variables, as usual, are the interval between consecutive samples, the sample size, and the distance away from the in-control process mean at which the control limits are placed. Costs considered are those of sampling, false ala...

In today's fiercely competitive marketplace, firms are looking for ways to improve their profitability. Computer simulation studies comparing group technology/cellular manufacturing (GT/CM) to job-shop layouts addressed this topic. However, each study ignored some of the most basic operating conditions said to give GT/ CM its advantages: this simul...

A common approach used in quality or process improvement is cause-and-effect analysis. It involves identifying a (large) number of possible causes of an undesirable effect or problem, and then choosing the sequence of investigation of the possible causes. The philosophy of continuous improvement dictates that any associated modelling should use rel...

Considering the strategic importance of business process improvement, it is imperative that educators, students, and practitioners be familiar with this topic. Thus, the intention of this tutorial is to provide a guiding framework for carrying out improvements of business processes. We present numerous illustrative examples, taken from our personal...

The primary issue addressed in this research is how to schedule clients as they call for appointments, without knowing which "types" of clients will call at a later time. The main goal is to compare various scheduling rules in order to minimize the waiting time of the clients as well as the idle time of the service provider. Interviews with recepti...

In an endeavor to broaden the application of scheduling models to decisions involving the use of a manager's time we use simulation to investigate the performance of a number of simple algorithms (including eight priority rules and a construction heuristic) in a dynamic setting with tasks arriving (randomly) and scheduling decisions being made, ove...

A number of articles have recently appeared proposing the use of NPV and similar economic scheduling performance measures. Much of this research has concentrated on developing methods to maximize NPV. However, it is assumed in almost all these studies that the cash flow information and cost rate parameters are all known with certainty. For confiden...

This paper attempts to integrate some of the recent research on several different aspects of scheduling production systems where early shipments are forbidden. In particular, this paper focuses on scheduling-rule development, order-release policies, due-date-setting policies, and the use of overtime on a selective basis. In addition, multiple perfo...

Recent research has considered the use of economic objectives in production scheduling environments as opposed to the classic time-based measures prevalent in the literature and in practice. This paper presents a comparison of both types of objectives to determine how differently the objectives select scheduling methods and how much economic loss o...

In a recent paper, Christy and Kanet (1990) examined the performance of several dispatching rules in a forbidden early shipment environment. Their primary performance measure was time-weighted inventory value. This study re-examines their results using a new model, with a net present value (NPV) performance measure. The results show that using NPV...

Thesis (Ph. D.)--University of Minnesota, 1992. Includes bibliographical references.

Both practitioners and researchers in the field of Operations Management have suggested that shop scheduling should be an integral component in both the strategic and tactical plans for an organization's assets. This paper examines the use of an accepted measure of return on assets, net present value (NPV), in a simulated shop scheduling environmen...

Both practitioners and researchers in the field of Operations Management have suggested that shop scheduling should be an integral component in both the strategic and tactical plans for an organization's assets. This paper examines the use of an accepted measure of return on assets, net present value (NPV), in a simulated shop scheduling environmen...

This paper addresses the question of whether there is a conceptual model that can explain operational risk in a wide range of organizations. It utilizes case studies and other research literature to build on the foundation laid by previous modeling research into system failures. The validity of the model is tested by how well it fits the parameters...

Patient appointment booking, sequencing, and scheduling decisions are challenging for outpatient procedure centers due to uncertainty in procedure times and patient attendance. We formulate a model based on a two-stage stochastic mixed integer program for optimizing booking and appoint-ment times in the presence of uncertainty. The objective is to...