Planning Capacity for Mental Health and Addiction Services in the Emergency Department: A Discrete-Event Simulation Approach
Table 2
Input parameters in the simulation model.
Parameter
Data/method
Details
Interarrival rates
Exponential distribution fit to historical ED arrival data
Interarrival rate distributions were separately created for the NMHA group and each MHA subgroup: substance abuse, schizophrenia, mood, anxiety, and others
Flow paths and proportions
Calculated from historical data
Proportions of patients in each acuity level (CTAS 1 to 5) were calculated. For each acuity level, proportions of each discharge disposition were also computed (i.e., discharged, admitted, internal transfer, external transfer, and left/death)
ED bed requirement
LogNormal distribution and average values fit to historical ED LOS data
Separate distributions were created for each acuity and discharge disposition combination
ED bed capacity
Supplied by ED manager
32 beds
PESU bed capacity
Supplied by PESU manager
6 beds
PESU LOS
Triangular distribution supplied by PESU manager
Minimal data were available, so estimates were used and validated by the PESU manager
