1. Department of Emergency Medicine, Madigan Army Medical Center , JBLM, WA 98431, USA
2. The Geneva Foundation , Tacoma, WA 98402, USA
3. TeleMentored Ultrasound Supported Medical Interventions Research Group, University of Calgary , Calgary, Alberta T2N 1N4, Canada
4. School of Industrial Engineering, Purdue University , West Lafayette, IN 47907, USA
5. Department of Emergency Medicine, William Beaumont Army Medical Center , Fort Bliss, TX 79918, USA
6. Department of Emergency Medicine, University of Maryland Medical Center , Baltimore, MD 21201, USA