Mathematical determination of external defibrillators needed at mass gatherings

To develop a mathematical formula that assists in determining the number of automated external defibrillators (AEDs) needed at sites of mass gatherings. Twenty (10 male, 10 female) healthy volunteers (equally divided between age groups 21–30 and 31–40 years) responded to mock cardiac arrests in a sp...

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Bibliographic Details
Published in:Prehospital emergency care 2004-07, Vol.8 (3), p.292-297
Main Authors: Crocco, Todd J, Sayre, Michael R, Liu, Tiepu, Davis, Stephen M, Cannon, Christopher, Potluri, Jagadish
Format: Article
Language:English
Subjects:
Adult
cardiac arrest
defibrillation
Electric Countershock - instrumentation
Electric Countershock - utilization
emergency medical services
Emergency Medical Services - utilization
Female
Heart Arrest - epidemiology
Heart Arrest - therapy
Humans
Male
mass gathering
Models, Statistical
Needs Assessment - statistics & numerical data
Public Facilities
Sports
Time and Motion Studies
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Summary:To develop a mathematical formula that assists in determining the number of automated external defibrillators (AEDs) needed at sites of mass gatherings. Twenty (10 male, 10 female) healthy volunteers (equally divided between age groups 21–30 and 31–40 years) responded to mock cardiac arrests in a sports stadium. Seven different first-responder scenarios were simulated (ascending and descending three separate stairway slopes (22°, 39°, and 69°), as well as a response across a horizontal (0°) surface. To assess the impact of spectator congestion, the same volunteers conducted each scenario in an empty and full stadium. The quantitative relationship between time and distance was then plotted for each situation. Using the quantitative relationship, the area a first responder can cover in a specified time was calculated. The formula for the total number of AEDs needed in a stadium (or other mass gathering site) can be expressed as follows: Total AEDs=[A1/(Ds1×Dh1)]+[A2/(Ds2×Dh2)]+[A3/(Ds3×Dh3)] where A1, A2, and A3 represent the total areas of a stadium with a slight, moderate, or steep stairway slope, respectively; Ds1, Ds2, and Ds3 represent the stairway distance a first responder must ascend or descend for each slope; and Dh1, Dh2, and Dh3 are the horizontal distances a responder can run in the time remaining. Given a medical director's targeted response times and goals, the optimal number of AEDs required at a mass gathering can be calculated using time versus distance relationships. Future studies should evaluate the impact of the mathematically derived optimal number of AEDs at mass gatherings.
ISSN:1090-3127
1545-0066
DOI:10.1016/j.prehos.2003.12.010