Optimization of hospital sterilization costs proposing new grouping choices of medical devices into packages

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Abstract

In the current context of hospital grouping, resources’ sharing is a highly interesting strategy for cost saving. Works presented in this paper are focused on a specific type of material resource, sterile reusable medical devices (RMD).

Sterility is obtained through a regulated process, performed within hospital central sterilization service and preservation of this sterile state is ensured by a packaging.

This article proposes a methodology enabling new grouping choices of RMD into packages. It exploits an innovative sharing strategy, with the final goal to optimize the objective function corresponding to process and storage costs of the sterilization activity.

Introduction

Modernization of hospital structures has a twofold objective: Improving quality of care and reducing health care costs.

The first objective is to a high extent related to hygiene conditions. At this level, one of the major challenges is to prevent nosocomial infection. To achieve the second objective and reduce healthcare costs, the current trend of healthcare structures’ grouping highlights the economical interest of resources’ sharing.

To contribute to the achievement of the two aforementioned objectives, this paper proposes a resource sharing method for optimizing the inventory of reusable medical devices (RMD), while ensuring a continuously high hygiene level.

Within health facilities, any medical supply that is foreseen to be in contact with a patient must be sterilized. Sterile supplies or instruments (i.e., sterile devices) are either designed for single use or for re-use. Single use materials are already sterilized when purchased, while—at least partly because initial purchase of surgical instruments is very expensive—reusable devices needed for surgical operations are generally sterilized in centralized sterilization facilities.

The sterilization of RMD is a high-quality process, which ensures that sterilized devices can be safely used during any subsequent surgical case. For a detailed description of the sterilization process, one can refer to French legal requirements (e.g. Standard AFNOR FD S98-135, 2005).

Even though this is a cyclic process (Fig. 1), we shall consider that its first step is the use of the sterile device in the operating room. After use, the medical supplies are transported to the sterilization central service where all items (i.e., instruments) are thoroughly cleaned, inspected and assembled if necessary. All items must then be packaged individually or grouped in packages before sterilization. Next step is the packages’ sterilization. The last process step is the storage of the sterile RMD for future use. Before surgical case, a nurse will pick up sterile RMD in the storage to fulfill the requirements of the surgical case. She will transport them to the operating room and unpack them only there. This is the final process step.

The changing context of healthcare system, encourages hospitals to improve the quality of services while reducing the associated costs. Since this is a potential area for important cost savings, the streamlining of the sterilization activity stands as a major focus. However, a limited number of solutions for cost reduction can be implemented while fulfilling requirements of the French sterilization policy. As a matter of fact, reengineering projects shall not focus on core part of the sterilization process, which is the reason why our work was directed towards storage optimization.

In this study, we focused on reducing storage costs of RMD: The number of RMD is generally very high, more than 1000 references for a typical hospital, including several samples per reference, and thus bear a significant cost. To reduce the set of RMD, we have to focus on the type of RMD storage authorized by French laws only, i.e. sterile storage. We suggest to explore the route of shared level of RMD during the packaging step, since there is no policy nor recommendation providing guidelines on the way items could be grouped together in the same package. The shared level of a RMD corresponds to a level in which it is shared between different types of surgical cases, and not dedicated to one specific type of case.

The current trend in healthcare leads to group surgical suite and healthcare facilities in order to share equipments and transversal resources. Following this trend, the set of RMD increases, which makes this project of shared level even more strategic.

Packaging exists only to allow the storage with a guarantee of sterility for an average period of 2 months, since it acts as a microbial barrier. One should bear in mind that RMD are sterilized and stored inside packaging. Packages are only opened in operating room during surgical case preparation. This requirement makes RMD storage greatly different from storage as understood in industrial context.

A package consists of one or several RMD. In current practices, the grouping choice of the RMD into packages is close to be “one package for one surgical case”. In this configuration, RMD are dedicated to one type of surgical case only. The shared level is consequently not exploited and storage costs are not optimized.

The goal of the work presented on this paper is to propose a route for costs reduction, optimizing RMD storage. This seems to be possible through the definition of new grouping choice strategies.

The issue, detailed in Section 2, consists in finding a grouping choice that optimizes a multi components’ cost function, which includes storage costs, in a context of combinative explosion of grouping choice possibilities.

This problem was previously studied (e.g. Reymondon and Marcon, 2005) but previous works were not successful in treating a real size problem. In Section 3 of this paper, a methodology is proposed to reduce the complexity of the problem: Its principle consists in identifying RMD types presenting a potential shared level and to focus only on these specific types.

Experiments have been performed and results are described in Section 4, while conclusion and prospects are presented in Section 5.

Section snippets

Problematic

This section defines the problematic, presenting the objective function, the mathematic formulation and the complexity. The shared level is also defined, since it is fully part of the problematic addressed.

Methodology

To find a hybrid grouping choice enabling the optimization of the objective function, it is necessary to find a methodology with a run time equal to a few days, which is acceptable because this study has to be performed only once a year since the frequency of the evolution of the RMD set and of the surgical activity is low.

Results

The data collection is a really difficult task because hospital information systems are for the time being really newer and less developed than information systems in industrial companies. Nevertheless, this is evolving very fast, and healthcare policy encourages this dynamism. Consequently, for this experimentation, results are based on a real size dataset but not on a real hospital case.

The dataset studied considers 150 types of surgical cases and 1000 types of RMD. A selected hypothesis is

Conclusion and future works

The methodology stage one has been applied and the results show that it is possible to significantly reduce the complexity. The methodology stage two—not yet experimented—will start from this new grouping choice and will transform it. But in this second stage, we will focus only on RMD shared by many surgical cases that represent only ten percent of all RMD. Thus reducing greatly the size of the dataset, so the complexity.

Furthermore, results obtained after stage one already improve the current

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There are more references available in the full text version of this article.

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