2% (9/755) if all non-responders represented EMS services not using ultrasound. Respondents were limited to those currently on mailing list of a professional organization, the National Association of EMS Physicians. Although we believe this mailing list is widely inclusive of our target population, it may not be all-inclusive. Our survey

response Inhibitors,research,lifescience,medical rate of 30% is comparable to other surveys of EMS providers using this survey method [30]. Another limitation arises because not all medical directors completed all sections of the survey. As a result these sections may have some bias in their responses. This phenomenon has previously been reported in surveys of EMS providers [30]. To mitigate this, each question of the survey was analyzed independently based on Inhibitors,research,lifescience,medical the number of respondents to that particular question. Conclusions Currently,

prehospital ultrasound is infrequently used in North America and EMS services identified a number of barriers to implementation. Current ultrasound use is associated with services with advanced trained providers. Decreased cost for equipment and training may make ultrasound a more feasible expenditure for EMS services. Two commonly used indications that could be a focus of standardized training programs are the FAST exam, and assessment of PEA arrest. A research agenda for prehospital Inhibitors,research,lifescience,medical ultrasound may be beneficial and should focus on the impact of prehospital ultrasound on patient outcomes. Abbreviations AAA: Abdominal aortic aneurysm; EMS: check details Emergency medical services; FAST: Focused abdominal sonography for trauma; IVC: Inferior vena Inhibitors,research,lifescience,medical cava; JVP: Jugular venous pressure; NAEMSP: National Association of EMS Physicians; NREMT: National Registry of Emergency Medical Technicians; PEA: Pulseless electrical activity; USA: United States of America. Competing interests The authors have no real or potential conflicts of interest to declare. Authors’ contributions JT developed the research proposal, wrote the ethics application, wrote the grant application, developed the survey, organized and distributed the survey, entered and analyzed data, and Inhibitors,research,lifescience,medical was the primary author of final

manuscript. KM developed the research question and assisted with the proposal, and he provided expertise in the area of emergency ultrasound. He assisted with ethics application; grant application, survey development and edits of final manuscript. the AM assisted with ethics application, grant application, survey design, data analysis and edits of final manuscript and provided expertise in statistical analysis. EL assisted with ethics application; grant application, survey design, data analysis and edits of final manuscript and provided expertise in research methodology. AA assisted with survey design, distributed pilot survey, assisted with edits of final manuscript and provided expertise in prehospital care. All authors read and approved the final manuscript.