1. Department of Emergency Medicine; Yale University School of Medicine; New Haven CT
2. Department of Emergency Medicine; Arizona Emergency Medicine Research Center; University of Arizona; Tucson AZ
3. Department of Emergency Medicine and Ottawa Hospital Research Institute; University of Ottawa; Ottawa ON Canada
4. The Arizona Department of Health Services Bureau of Emergency Medical Services and Trauma System; Phoenix AZ
5. Maricopa Medical Center; Phoenix AZ
6. Department of Preventive Medicine and Community Health; University of Texas Medical Branch; Galveston TX
7. Division of Emergency Medicine; Western University; London ON Canada