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THE UNIVERSITY of TEXAS – SAN ANTONIO
Mechanical Engineering Department
Simulation with Arena: waiting time in emergency room (Methodist hospital
San Antonio Texas)
Adrien Tiokeng & Alireza Ahmadi
Project Abstract
Today, Emergency room has an important role of saving people lives. Each hospital around the
nation try to build better processes for reducing wait time in Emergency room for giving better
service for their patients. The purpose of this research study was observation of amount of
waiting time process in Emergency room of Methodist Hospital at San Antonio Texas, and help
the emergency department for improving the waiting time base on observation data. There is two
group of people base on their health situation come to Emergency room to see doctor for curing
their problems. First category, consist of people with critical health situation which majority
come to Emergency Department of hospital by Ambulance. This category should have less
waiting time. Second category, consist of people with less critical health situation. This category
usually shows up at triage of emergency department and base on their arrival time, they will wait
until to see E.R doctors.

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I. ARENA Model, which should contain:
 Model diagram +Appropriate graphics

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 Resources + Schedule
Table 1: Resource Table

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Table 2: Arrival time Schedule
Figure 1: Ambulance Arrival time schedule

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 Entities, attributes, queue, ...
Table 3: Entity- basic process
Table 4: Attribute- Basic Process
Table 5: Queue- Basic Process

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 Graphs, supplementary Statistics, variables .... (as necessary)
Figure 2: Queue Surgery vs. Time (Hours)
Figure 3: Queue Specialist vs. Time (Minutes)

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Figure 4: Queue General Medicine vs. Time (Minutes)
Table 6: Statistical of Recourses of General Medicine

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Table 7: Statistical of Recourses of Specialist Statistics
Table 8: Statistical of Recourses of Surgery Statistics

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II. ARENA generated report
ARENA report consist of:
 Category by replication
 Category overview
 Entities
 Frequencies
 Queues
 Resources
III. Analysis of the report
 Category by replication
This category contains of six replications about 12 hours of schedule. As an example the
First replication, the average, Minimum and Maximum number of the patient in schedule for
non-critical case General Medicine are 4.25, 2.0, 5.0. Also, on scheduled utilization for 18
number of patient out the non-critical case general medicine had register 0.1807. On
replication number 1, the waiting time for emergency department base on observation data
from hospital is zero because it is maximum priority of ambulance arrivals. On replication 2
is representing the average waiting time of emergency deferment triage for walking arrival
to emergency department is about 4.82 minutes (0.00695 x 12.00 hours’ x 60 minutes).
(See Attachment of Category by replication PDF file).
 Category overview
This project contains of 6 replications. The Queue of emergency department had an average
of waiting time 6.48 minutes and minimum average is zero and maximum average is 19.44
minutes and the maximum 1.82 hours.
 Entities
In average for entities is 18, the min is 15 and maximum is 25.

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 Frequencies
The statistic applied in this model had been implemented by using the frequency on arena
simulation. Thus, on general medicine statistic with the range of between 0 and 5 of quantity
of patient needed one doctor and between 5 and 10 of quantity of patient needed two
doctors, between 10 and 15 of quantity of patient needed three doctor and between 15 and
20 of quantity of patient needed four doctors
 Queues
 Resources

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IV. Specific tasks of each member of the project team including the Amount of
time spent for each tasks
References
W. David Kelton, R. P. (2010). Simulation With Arena Fifth Edition. New York: McGraw-Hill.