Optimization of tray inventory levels in hospitals from an integral perspective.

Surgical instrument trays are crucial for any hospital’s surgical department; patients cannot undergo surgery if the right instruments are not available. It is therefore of great significance to provide a steady and sufficient supply of sterile medical devices to the surgery department, which can be guaranteed by having sufficient inventory of sterile trays. However, the value of surgical tray inventory is substantial, and given the pressure on the health care industry to reduce cost, a properly aligned tray inventory is of utmost importance. Choosing the appropriate tray inventory levels is hard due to the complex interplay between the surgical schedule and the sterilisation cycle. In this paper, we propose a practice-driven heuristic and a Discrete Event Simulation (DES) model to choose and evaluate the appropriate tray levels respectively. We propose a novel surgery schedule generation algorithm to account for the dependency in tray demand, which has not been addressed in literature thus far. Using a case study from our partnering hospital, we show that without compromising quality, the tray inventory can safely be reduced by 28%.