A hybrid inventory control policy for medical supplies in hospitals

Abstract

In this thesis, we consider the inventory control problem of medical supplies that arises in a particular hospital environment. The items are stored in nursing stations from where they are retrieved by the nurses and used for the needs of in-patients or out-patients. The nursing stations are replenished from a central warehouse. Items are moved between the hospital’s central warehouse and the nursing stations by a capacitated porter cart. In the representative nursing station that we analyze, the need for the medical supplies by the in-patients can arise at any time during day or night. It is possible to replenish the nursing stations during the day time on a continuous scale; however, this is not possible after-hours because the warehouse operates only during regular working hours. For this particular setting, we propose a hybrid inventory control policy which consists of a continuous review joint replenishment policy to manage the day time demand and a periodic review policy to manage the night time demand. The prior performance measure is set to satisfy the target service levels in the nursing stations. For a special case of the problem with a single item, we develop exact expressions to estimate the policy parameters. For the multi-item case, we analyze the impact of the policy parameters on the service level targets by simulating a representative system under different scenarios. Finally, we analyze a sample data collected from a nursing station and prescribe methods to determine the policy parameters