• Vol. 38 No. 6, 508–514
  • 15 June 2009

Predicting Positive Blood Cultures in Patients presenting with Pneumonia at an Emergency Department in Singapore



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Introduction: This paper aims to illustrate the use of computer simulation in evaluating the impact of a prototype automated dispensing system on waiting time in an outpatient pharmacy and its potential as a routine tool in pharmacy management. Materials and Methods: A discrete event simulation model was developed to investigate the impact of a prototype automated dispensing system on operational efficiency and service standards in an outpatient pharmacy. Results: The simulation results suggest that automating the prescription-filing function using a prototype that picks and packs at 20 seconds per item will not assist the pharmacy in achieving the waiting time target of 30 minutes for all patients. Regardless of the state of automation, to meet the waiting time target, 2 additional pharmacists are needed to overcome the process bottleneck at the point of medication dispense. However, if the automated dispensing is the preferred option, the speed of the system needs to be twice as fast as the current configuration to facilitate the reduction of the 95th percentile patient waiting time to below 30 minutes. The faster processing speed will concomitantly allow the pharmacy to reduce the number of pharmacy technicians from 11 to 8. Conclusion: Simulation was found to be a useful and low cost method that allows an otherwise expensive and resource intensive evaluation of new work processes and technology to be completed within a short time.

Pneumonia is the fourth leading cause for hospitalisation, and the third leading cause of death in Singapore.1 Overall, it is consistently one of the most expensive diseases to treat among elderly persons with multiple co-morbid conditions,2 a challenge to our healthcare system with a rapidly ageing population. Treatment guidelines for pneumonia invariably recommend performing blood cultures. This practice has become a major area of resource utilisation, despite the poor yield of blood cultures.

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