1. University of Washington-Harborview Center for Prehospital Emergency Care, Division of Internal Medicine, Seattle, Washington.
2. The Essex Cardiothoracic Centre, Basildon and Thurrock University Hospitals NHS Foundation Trust, Basildon, United Kingdom.
3. Department of Emergency Medicine, Skane University Hospital, Lund University, Lund, Sweden.
4. Department of Emergency Medicine, University of Alabama at Birmingham, Birmingham, Alabama.
5. Departments of Neurology, Neurosurgery and Emergency Medicine, Kings County Hospital/SUNY Downstate College of Medicine, Brooklyn, New York.