Evaluating Replenishment Systems for Disposable Supplies at the Operating Theater: A Simulation Case Study

Abstract

Ensuring cost containment while providing high quality patient care is of paramount concern to hospitals. The operating theater in particular is a major cost driver for any hospital, and is among the most critical resources in terms of both capacity and patient care. Effective inventory and distribution systems are a prerequisite for realizing efficiency improvements in the internal operating theater supply chain. In this work, discrete-event simulation is used to model part of the internal distribution process in the operating theater at a Belgian Hospital and to identify improvements by focusing on the replenishment process. A logistics performance measurement framework based on Analytic Network Process (ANP), as a popular Multi-Criteria Decision-Making (MCDM) technique, is adopted to assess three replenishment scenarios. The best performing scenario is selected using the Internal Logistics Efficiency Performance (ILEP) index as an evaluation basis. This research indicates that industrial engineering techniques, such as simulation and MCDM, which are successfully applied in industrial sectors, can also be adopted to realize efficiency opportunities in healthcare logistics.

Appendices

Appendix 1

Quality	Quality specifies how well a specific activity has been performed, ensuring that patients receive care service in a safe manner and that problems such as medical errors are minimized
	Distribution service level (DSL)	The availability of logistics services to support clinical care processes
		Urgent delivery rate	${\text{Daily stock}} - {\text{out rate}} = \frac{{\mathop \sum \nolimits_{{{\text{i}} = 1}}^{{{\text{i}} = 454}} ({\text{Stockout}}_{\text{i}} )}}{{730\,{\text{days}}}}$
		Additional items needed	${\text{Average replenishment per item}} = {\text{AvgMaxStock}} - \frac{\text{Average daily replenishment}}{\text{Average replenishment items per day}}$
	Delivery accuracy (DA)	The ability to pick and deliver the correct items and quantities from storage to point-of-use location
		Perfect order fulfilment	${\text{Daily number of incomplete refills}} = \frac{{\mathop \sum \nolimits_{{{\text{i}} = 1}}^{{{\text{i}} = 454}} \left( {{\text{MaxStock}}_{\text{i}} - {\text{ItemsInStock}}_{\text{i}} } \right)}}{{730\,{\text{days}}}}$
	Centralization impact (CI)	The ability to locate items only at a central storage room, or also at decentral storages.
		Permanent double stock	Number of copy carts, containing duplicate of items in decentral storages
		Impact of centralization	Adjust max stock in decentral locations
Time	Time involves the time to complete the logistics operations to ensure that the right items are at the right place and time
	Replenishment lead time (RLT)	The total amount of time that elapses from the moment an item is ordered until the item is back on the shelf
		Transport time	Time to move items to the right place
		Replenishing time	Time to replenish decentral stock
		Scanning time	Time to scan items in decentral stock
		Preparing time	Time to pick requested items from central stock
		Other activities time	Time spent on other activities than replenishing due to interruptions
		Replenishment lead time	$= {\text{Transport}} + {\text{replenishing}} + {\text{scanning}} + {\text{preparing}} + {\text{other}}\,{\text{activities}}$
	Response time (RT)	The ability to deliver items on time, preventing delays in surgical procedures
		On-time delivery	Average delivery time = finish time of replenishing decentral stock
	Clinical staff involvement (CSI)	The amount of time clinical staff is busy with logistics tasks, rather than their core activities
		Logistics employees involvement	Time spent by logistics employees (=RLT—other activities)
Financial	Financial indicators identify supply chain cost drivers, such as expenses incurred by departments for providing services, including direct and overhead costs for inventory and internal distribution
	Distribution cost (DCo)	Total cost of handling and transporting to move supplies from storage rooms to point-of-care locations
		Replenishing cost	Related to RLT
	Personnel cost (PCo)	The cost related to the time personnel is involved with logistics activities
		Personnel cost	Related to CSI
	Inventory cost	The annual cost of holding inventory at a specific storage room
		Holding cost	${\text{Average holding cost}} = [\mathop \sum \nolimits_{{{\text{i}} = 1}}^{{{\text{i}} = 454}} \left( {\frac{{{\text{ItemsInStock}}_{\text{i}} }}{\text{InventoryCount}}} \right)]*{\text{UnitCost}}_{\text{i}} *0.25$
Productivity/organization	Productivity/organization involves operational control metrics for logistics departments used for streamlining processes, reducing costs, facilitating information flow and enhancing provided care services
	Case cart efficiency (CCE)	The availability and utilization of case carts to provide surgeons with the required supplies
		Not applicable for replenishment process
	Delivery frequency (DF)	The number of visits to decentral storage locations to deliver or replenish items in these locations
		Percentage of items replenished	${\text{Daily percentage of item replenishment}} = {\text{Total}}\,{\text{items}} - \frac{\text{Daily number of items replenished}}{\text{Total items included}}$
		Scanning frequency	Use of scanner (0/1)
		Visits to decentral locations	Number of opening relay cabins
	Standardization (S)	The ability to simplify workflows between operating rooms and improve working conditions
		Percentage of scannable items for replenishment	$= {\text{Total items}} - \frac{\text{Number of scannable items}}{\text{Total items}}$
	Personnel management (PM)	A measure of how to obtain, use and maintain a satisfied workforce
		Personnel utilization	$= \frac{{{\text{Time busy replenishing }}\left( {\text{RLT}} \right)}}{{480\,{ \hbox{min} }}}$
		Ergonomics friendliness	Use of double carts (0/1)
		Workload distribution	Timeline of logistics employees interrupted by other activities

Appendix 2