Surgical Surge Capacity of Operating Rooms and Resultant Delay to Treatment During Mass Casualty Incidents: A Queueing Model

INTRODUCTION: Operating rooms (ORs) are a constant and critical bottleneck during mass casualty incidents (MCIs). The study aim was to develop a queuing model estimating surgical surge capacity and resultant patient delays during MCIs. MATERIALS AND METHODS: A computerized queueing model was developed to assess OR surge capacity and delays. Waiting times were calculated based on the number of ORs, estimated surgery durations, and OR availability across different MCI timings (day/night/weekends). RESULTS: In a facility with 30 ORs, if 25 are occupied at the onset of MCI, each additional patient causes an average 4-minute delay once full surgical capacity is reached. This accumulates such that the #14 casualty waits ∼60 minutes, and the #27 casualty waits ∼120 minutes. When only 2 ORs are active (e.g., at night), each added patient extends the queue by ∼5 minutes. CONCLUSIONS: This easy-to-calculate model predicts delays to surgery and assists in critical operational decision-making such as practicing secondary evacuation.