Development of a discrete event simulation model for evaluating strategies of red blood cell provision following mass casualty events

Timely and adequate provision of blood following mass casualty events (MCEs) is critical to reducing mortality rates amongst casualties transported to hospital following an event. Developing planning strategies to ensure the blood transfusion demands of casualties are met is challenging. Discrete event simulation (DES) offers a novel solution to this problem which is financially efficient, less disruptive to services and allows for rich experimentation compared to the current industry standards of live exercises, round-table discussion or tabletop planning. There are currently no published models of this type for investigating blood provision in MCEs. The objective of this study was to develop a working model which could be used to target the in-hospital 'levers' and 'supply levels' of the transfusion system and improve outcomes during the response to future events. This was achieved through the robust design of a DES model using exclusive access to qualitative and quantitative data as well as a panel of experts from the field of transfusion and MCE management. The completed model was extensively and formally evaluated with secondary data from the 7th of July 2005 London bombings, the largest UK based civilian MCE in over 50 years. A subsequent sensitivity analysis revealed the five factors displaying the greatest influence on casualty outcomes. Experimental themes based on these findings have generated new solutions for managing future events which have since been presented to MCE stakeholders and policy makers.