Point of Dispensing Model

Model Description

Staffing of Points of Dispensing (PODs) of medications in a biological event requiring mass prophylaxis is problematic, because of expected outage due to illness among staff members and general shortages of medical personnel. Simulation analysis can assist with balancing staffing among POD functions for maximal dispensing throughput with the available staff.

In the POD simulation model, four types of patients are generated: Type E (Express), Type S (Screening needed), Type C (Counseling needed), Type T (Translation needed), and Type D (Divert to hospital). Each call type has its own rate of occurrence in the population, which is set at a generate activity inside the GenPatients simulation activity.

The POD is staffed by various types of medical resource persons:

  • Screeners, who determine what medications can be given to the patients
  • Consultants, who work with difficult patients to establish medical needs
  • Translators, who screen patients in languages other than English
  • Dispensers, who dispense prophylactic medications
  • Medical Evaluators, who divert sick patients to hospitals
The numbers of each type of staff member type available in the model are model parameters that the user can change each time the simulation is started. This is done by means of a dialog box that opens automatically. The user changes the model staff parameters from that dialog. Some typical staff counts are represented in the summary of five model runs shown in the table below:
Resource Run 1 Run 2 Run 3 Run 4 Run 5
Screener 18 18 18 18 18
Consultant 2 2 2 2 2
Translator 3 3 3 3 3
Medical Dispensing 4 6 8 9 7
Express Dispensing 2 2 2 2 2
Forms Assistant 4 8 8 8 8
Medical Evaluator 1 1 1 1 1
For security reasons, no more than a specified number of patients can be in the POD at any time. Others must remain queued up outside the POD. Simulation study can be used to estimate line lengths at POD activities in relation to the staff complement. The POD model includes a number of relevant real-time plots that can be used to evaluate the line lengths in the dispensing queues. It can be seen from the Dispense Wait graph, for instance, that the number of patients in line for an allocation of 7 dispensing persons is often between 5 and 20 persons waiting. Increasing the number of dispensers to 9 reduces this waiting line to a more acceptable value of 1 or 2 patients.

The objective is to achieve maximum patient throughput over the 48-hour operation of the POD while using the minimum staff. The model patient throughput and POD processing times for the four parameter sets above are shown in the following table:


Outcome Run 1 Run 2 Run 3 Run 4 Run 5
Number Processed 12816 15187 15905 15897 15860
Min Time (Minutes) 2.3 2.3 2.3 2.3 2.3
Max Time (Minutes) 589 137 11.4 11.1 13.4
Avg Time (Minutes) 441 100 8.2 8 9.5
From this study, it could be concluded that the parameter staffing of Model 3 or Model 4 gives the greatest throughput for the staff required and allowable line length. Note that the additional Medication Dispensing staff member between Models 3 and 4 does not contribute significantly to throughput. This staff member could be transferred to another activity or another POD.

This model was built using advanced features available in SIMPROCESS Professional.

Demonstration Model

In order to view the demonstration model you must have SIMPROCESS installed on your computer and you must have a license. If you don’t have SIMPROCESS you may download a trial version.

You must save the demo model file by RIGHT CLICKING on the file below and select “Save Target As”. Save the file to your computer. After you launch SIMPROCESS select File and Open. Then navigate to where you saved the demo file and select to open it.

Additional demonstration models are in the models/Demos directory which is located in the SIMPROCESS working directory.