Surgical Surge Capacity of Operating Rooms and Resultant Delay to Treatment during Mass Casualty Incidents: A Queue Management Model

Introduction: This study aimed to develop a useful model for calculating the surgical surge capacity and consequent delays in delivering care during mass casualty incidents (MCIs). Methods: A queue management model was developed using operational research tools, and a computer code was written for that end. The waiting times were calculated according to the number of existing operating rooms (ORs), surgical time estimations, and expected OR availability (days/nights/weekends). Results: A facility with 30 ORs, of which 25 are occupied at an MCI onset, will experience a 4.1-minute delay with every additional patient, once all rooms are operating, when the ordinary mean surgical time is 120 minutes for non urgent cases and 150 minutes for emergency surgeries. This translates into the mean added time for each additional patient, such that casualty #14 will wait ~60 minutes and casualty #27 will wait ~120 minutes. For an MCI occurring when there are only two busy ORs (e.g., nights or weekends), every patient added to the queue will lengthen the postponement by ~5 minutes. A facility with 20 ORs, of which 15 are occupied at an MCI onset, will experience a 6.3-minute delay with every additional patient, once all rooms are operating, when the ordinary mean surgical time is 120 minutes for non-urgent cases and 150 minutes for emergency surgeries. This is the mean added time for each additional patient – casualty #9 will wait ~60 minutes, and casualty #18 will wait ~120 minutes. If the MCI started with only two working ORs, every patient would add ~7.5 minutes to the queue once it has formed. Conclusion: The queue management model is based upon the overall number of ORs, the timing of the MCI, and the operating time estimations. This easy-to-calculate model predicts delays to surgery and assists in critical operational decision-making.