Evaluation of the impact of Queueing Policies on the waiting time of Patients on a Hospital Dispensary

Abstract

In general, the last step on a patient pathway is the issuance of the prescribed medicine by the hospital pharmacy or dispensary, where the waiting times at this stage may have a high level of impact, for better or worse, on the patient's perception of the quality of the hospital's service. In theory, there are two ways of reducing these times: by improving the speed of the different stages within the whole process, generally through the implementation of newer technologies, or by reducing the queueing times between the stages, generally through the management of the queues. This dissertation will focus on the latter, by evaluating the effects of different queueing policies on the waiting time of patients at the Great Ormond Street Hospital dispensary. In order to do this, a discrete event simulation model was developed to emulate, together with historic data about the arrival and processing times, the daily operations at the dispensary. Then, several scenarios with different policies and staff flexibility were generated and compared in terms of the benefits and drawbacks on the waiting time of patients. The results obtained suggested that, despite the fairness of a first-in-first-out policy, the shortest processing time policy could benefit around 90% of the patients at the expenses of the remaining 10% by reducing the total waiting time of patients, in average, in more than 10%. However, the shortest processing time queueing policy requires to have at least an idea on how long a prescription would need to be processed. Therefore, the recommended method to implement the SPT policy in the short-term is by categorizing prescriptions in “short”, “average” and “long”, while for the long-term an optimisation model could be developed to select which prescription to process next based on past data, the current dispensary status and the objective and constraints of the dispensary.