The gathering of a large number of people together presents unique challenges for medical support, both logistically ands with regard to the wide variety of potential medical problems. For example, the density of the
population at these events lends itself to the possibility of high numbers of victims in the event of a terrorist event as well as logistic difficulties in terms of triage, treatment, and transport. It is therefore important to have a well-prepared plan for all contingencies.

Since the dawn of history humans have gathered for pilgrimages, and fled en masse from famines, floods, and oppression in large numbers. Some of the earliest recorded include the biblical journey of Moses and the Israelites across the Egyptian desert and the first pilgrimage to Mecca in 628 AD, as Mohammed led 1,400 followers on the first Hajj (7). The Hajj has become the largest mass gathering in the world, with up to 4 million worshippers traveling to Mecca each year (8).

The first step in the medical preparation for an event is to define and assemble the event planning committee. For a major event, this should occur at least a year prior to the event date (Table 31.1) and consist of the event coordinator, the medical director, EMS, venue public safety/security, fire protection, and law enforcement. The TEMS provider should take part in this planning process when possible. This early coordination is important for an effective response between the TEMS unit and the event medical staff. Having a good understanding of the Incident Command System (ICS) and having the event integrated into the local ICS is essential for mass gathering planning.

The event coordinator is responsible for coordinating the entire event (of which medical care is one part) and is often the key person in terms of logistical and financial support. The medical director is responsible for coordinating all aspects of medical care for the event, from triage and on-site first aid, to stabilization and transportation, to disaster planning. It is also the responsibility of the medical director to make sure that whatever plan is developed can be smoothly integrated into existing plans of EMS/fire/law enforcement/secret service or any other agency’s preexisting plan. EMS plays a vital role in most mass gatherings and should be included in the planning for medical care from the start. While the traditional role of EMS is certainly useful, there are several studies (9, 10 and 11) showing that protocols can be devised to expand their usual scope of practice to include a number of different treat and release scenarios. The roles of venue security and local law enforcement (including the TEMS team) need to be clearly defined. Crowd control, access to and egress from the event site, and the response to a terrorist incident are areas where they will have the lead role. How transfer of care occurs between the TEMS team and the event medicine team should also be addressed. The local fire service can supply information regarding the planned response to the event and should be made aware of any chemicals, pyrotechnics, or other fire hazards caused by the event (12). Many states, counties, municipalities, and local governments also have plans and legislation concerning mass gatherings. In planning for any event, these local and state guidelines should be sought out and integrated. In the event of a mass casualty incident (MCI), the roles of all of the various agencies involved need to be determined, with the medical director
negotiating a position within the command center. Local disaster preparedness plans may assist in planning and preparing for a mass gathering event, and some localities may request assistance from the Federal Disaster Medical Assistance Teams (DMAT) in their area. DMAT teams are often willing to participate, as the event also acts as training for their team.

Profiling of the event itself is vital in planning for the necessary medical care. There is a myriad of variables that affect the volume of patients as well as the types of medical problems likely to be encountered. These, in turn, define the amount and type of staffing that will be needed.