Modelling Red Blood Cell Provision in Mass Casualty Events

Abstract

Traumatic haemorrhage is a leading preventable cause of critical mortality in mass casualty events (MCEs). Treatment requires the rapid provision of high volumes of packed red blood cells (PRBC) to meet the surge in casualty demand these events generate. The increasing frequency of MCEs coupled with the threat of more violent mechanisms risks overwhelming hospital based transfusion systems. The overall objective of this research was to improve understanding of blood use in MCEs using a mathematical modelling approach. A computerised discrete event simulation model was designed, developed and validated using civilian and military transfusion databases, a review of historical MCEs and discussion with experts involved in all aspects of in-hospital MCE PRBC provision. The model was experimented with across increasing casualty loads to optimise event outcomes under varied conditions of: stock availability, laboratory processing procedures and individual PRBC supply. The model indicated even in events of limited size the standard on-shelf PRBC stock level was insufficient to adequately meet demand amongst bleeding casualties. Restocking during an event allowed for equivocal treatment results if performed early following an event and this would be most effective if activated by central suppliers. Modifications to transfusion laboratory processing procedures were found to be of limited benefit in improving outcomes due to the principally automated nature of the techniques they employ. Conversely, the use of restricting excessive individual provision of both overall PRBC and emergency type O PRBC to individual casualties did show potential for managing scenarios where only a finite supply of stock existed or an accurate estimation of expected casualties was available.