Marilyn M. Anderson

Evaluating the Capability of Information Technology to Prevent Adverse Drug Events: A Computer Simulation Approach

BACKGROUND The annual cost of morbidity and mortality due to medication errors in the U.S. has been estimated at

THE NEED FOR ORGANIZATIONAL CHANGE IN PATIENT SAFETY INITIATIVES

76.6 billion. Information technology implemented systematically has the potential to significantly reduce medication errors that result in adverse drug events (ADEs). OBJECTIVE To develop a computer simulation model that can be used to evaluate the effectiveness of information technology applications designed to detect and prevent medication errors that result in adverse drug effects. METHODS A computer simulation model was constructed representing the medication delivery system in a hospital. STELLA, a continuous simulation software package, was used to construct the model. Parameters of the model were estimated from a study of prescription errors on two hospital medical/surgical units and used in the baseline simulation. Five prevention strategies were simulated based on information obtained from the literature. RESULTS The model simulates the four stages of the medication delivery system: prescribing, transcribing, dispensing, and administering drugs. We simulated interventions that have been demonstrated in prior studies to decrease error rates. The results suggest that an integrated medication delivery system can save up to 1,226 days of excess hospitalization and

Modeling the Costs and Outcomes of Cardiovascular Surgery

1.4 million in associated costs annually in a large hospital. The results of the analyses regarding the effects of the interventions on the additional hospital costs associated with ADEs are somewhat sensitive to the distribution of errors in the hospital, more sensitive to the costs of an ADE, and most sensitive to the proportion of medication errors resulting in ADEs. CONCLUSIONS The results suggest that clinical information systems are potentially a cost-effective means of preventing ADEs in hospitals and demonstrate the importance of viewing medication errors from a systems perspective. Prevention efforts that focus on a single stage of the process had limited impact on the overall error rate. This study suggests that system-wide changes to the medication delivery system are required to drastically reduce mediation errors that may result in ADEs in a hospital setting.

Evaluating the Impact of Information Technology on Medication Errors: A Simulation

OBJECTIVES This study describes a computer simulation model that has been developed to explore organizational changes required to improve patient safety based on a medication error reporting system. METHODS Model parameters for the simulation model were estimated from data submitted to the MEDMARX medication error reporting system from 570 healthcare facilities in the U.S. The models results were validated with data from the Pittsburgh Regional Healthcare Initiative consisting of 44 hospitals in Pennsylvania that have adopted the MEDMARX medication error reporting system. The model was used to examine the effects of organizational changes in response to the error reporting system. Four interventions were simulated involving the implementation of computerized physician order entry, decision support systems and a clinical pharmacist on hospital rounds. CONCLUSIONS Results of the analysis indicate that improved patient safety requires more than clinical initiatives and voluntary reporting of errors. Organizational change is essential for significant improvements in patient safety. In order to be successful, these initiatives must be designed and implemented through organizational support structures and institutionalized through enhanced education, training, and implementation of information technology that improves work flow capabilities.

HIV screening and treatment of pregnant women and their newborns : A simulation-based analysis

Coronary artery bypass graft (CABG) operations consume more health care resources than any other single procedure. The objective of this study was to develop a computer simulation model that can be used to predict costs and patient outcomes of CABG surgery. The analysis is based on a systems dynamic model developed using STELLA software. Two sets of data from Medicare patients who underwent CABG operations at Methodist Hospital of Indiana were used to construct and validate the model. The model predictions of length of hospital stay, use of specialists in caring for patients, costs and postoperative functional status are reasonably close to actual data on patients who underwent CABG surgery. The analysis indicates the most important factors affecting costs and outcomes are gender, age, whether or not the surgery is a reoperation and whether the patient experiences postoperative complications. The model can be used to predict costs and outcomes for a patient population from a small set of preoperative characteristics (i.e., age, gender, DRG, whether the surgery is a reoperation, and the patients operative status). A second potential use of the model is to answer clinical questions such as do the costs and risks of CABG operations outweigh the benefits for patients with certain risk factors.

Modifying Physician Test-Ordering Behavior in the Outpatient Clinic

Information technology has been shown to reduce med- ication errors and associated ADEs at every stage in med- ication administration. 1 Information systems include deci- sion support at the prescription stage, computerized physician order entry, unit dosing systems, and bar-cod- ing of individual medications among others. We devel- oped a computer simulation model and used it to evalu- ate the effectiveness of a number of information technolo- gy applications, individually and collectively, to reduce medication errors and associated ADEs. 2 The model incor- porated estimates from published studies of the potential reduction in medication errors that could result from implementation of various information technologies. Shojania questions two of these estimates, specifically potential reductions in errors from implementing bar- coding and unit dosing. We assumed that bar-coding medications potentially could reduce drug administra- tion errors by as much as 60%. This estimate is support- ed by other studies. Puckett 3 reports on the effect of the introduction of CliniCare, a point-of-care information system for medication management, in a primary and tertiary care center. All medications were bar-coded and scanned at or near the patients bedside. He reports a medication error rate of 0.17% before implementation of the system. In the following year the medication error rate dropped by 59% to 0.07% and during the next year to 0.05%, a 70% decrease. We estimated that the introduction of a unit dose system could reduce errors by as much as 80%. Unit dose sys- tems dispense most medications from the pharmacy in a ready-to-administer form and are widely used in U.S. hospitals. Studies that have evaluated the impact of unit- dose dispensing on medication errors report reduction in medication error rates ranging from 53% to 85%. 4-7 However, as Shojania points out, other studies have demonstrated mixed results from implementing some of these technologies. For example, an ethnographic study of the implementation of bar-code medication administration (BCMA) in several hospitals, while not reporting medication error rates before and after imple- mentation, found several side effects that created the potential for new ADEs. 8 Moreover, we do not know for certain how much of a reduction in error rates is associated with implementing unit dose and bar code systems in hospitals. This uncer- tainty is due to the limited number of studies, varied definitions and methodologies that have been used in the studies that have been performed, and the small number of institutions involved in these studies, mak- ing any one study subject to local and regional varia- tions in providers, patient populations, etc. As a result we reran estimates of the cost savings that could be expected from an integrated medication system that included unit dosing and bar-coding of medications assuming that error reductions resulting from these two applications would only be in the order of 40% and 30%, respectively. We estimated potential savings of over

Toward an integrated simulation approach for predicting and preventing technology-induced errors in healthcare: implications for healthcare decision-makers.

820,000 even with the lower rates, a significant impact of these interventions.

Evaluating the potential effectiveness of using computerized information systems to prevent adverse drug events.

Clinical trials have shown that HIV-positive preg nant women treated with zidovudine during preg nancy and delivery have a much lower rate of HIV transmission to their newborns. Recent studies have also shown the effectiveness of antiretroviral therapy combined with elective cesarean delivery and a short- term antiretroviral therapy. In this study a dynamic computer model was built. The model was used to estimate economic consequences of testing pregnant women for HIV virus and treating the HIV-positive women and their newborns with three different reg imens. Outcomes of data analysis included costs and the number of avoided cases of perinatal transmission of the HIV virus. The study found that while the over all costs of the three treatment programs were simi lar, the short-term antiretroviral program was the least cost-effective and prevented fewer cases of peri natal transmission of the virus. Sensitivity analysis found that the cost-effectiveness of the treatment pro grams were differentially sensitive to screening and treatment rates. Cost-effectiveness of all regimens is highly sensitive to the HIV infection rate among preg nant women. When the rate reaches four to five per 1,000, treatment cost savings from the reduction in pediatric HIVcases exceed the costs of screening and treatment. The model presented provides a useful tool to be used to evaluate treatment programs designed to pre vent mother-to-infant transmission of the HIV virus.

The Cumulative Influence of Conflict on Nursing Home Staff: A Computer Simulation Approach

The purpose of this study was to evaluate the use of structured order forms with a computerized medical information system to reduce the ordering of unnecessary outpatient tests. The study was implemented among house staff in the Family Practice Center and the Adult Ambulatory Care Center at Methodist Hospital of Indiana, a 1120 bed, private teaching hospital in Indianapolis, Indiana, U.S.A.