Disaster preparedness is absolutely necessary as the number of both man-made and natural disasters increases worldwide. Not confined to any regions or people, disasters can result in mass casualties. The United States is not spared from these incidents. Ever since the 9/11 terrorist attacks, the United States has tried to establish more effective and efficient emergency management systems at all levels in order to respond to any type of disaster. Due to the effort, much improvement in disaster preparedness was observed when mass casualty events happened within the last 10 years. Although there are many independent studies for each mass casualty event, there are very few studies done to compare multiple mass casualty incidents and find commonly shared lessons. This paper aims to determine whether there are any similarities among three mass casualty events - 2005 Hurricane Katrina, the 2009 Aurora Theatre Shooting, and the 2013 Boston Marathon Bombing. Because the response to the 2013 Boston Marathon Bombing was the most seamless among the three, the most in-depth investigation was done on this incident. Through the examination, the study will also prove if any of the lessons learned from these events can be implemented in future mass casualty incidents. To do so, many current reports and literature reviews were analyzed. The conclusion gained from this study is that there are indeed commonly occurring challenges in disasters and various aspects of disaster preparedness that require practice and preparation. In addition, learning from others' unfortunate mass casualty incidents and their lessons is an important part of strengthening the existing disaster preparedness systems.

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.