398 Emergency Medical Services and Bilateral Lung Ultrasound in Emergency (EMS BLUE) Study

Abstract

Out-of-hospital ultrasound is not yet widely implemented. Most studies report on convenience samples and trauma patients. We assessed the feasibility of paramedic performed out-of-hospital lung ultrasound in medical patients with respiratory distress. Paramedics at two ambulance stations in the city of Pittsburgh, PA, USA underwent a 2-hour training session in out-of-hospital lung ultrasound using the SonoSite iViz, a handheld ultrasound device. Emergency medical services (EMS) physicians were instructed in the interpretation of lung ultrasound images. Paramedics enrolled patients presenting with signs and symptoms of respiratory distress over a 3-month period. The ultrasound exam included anterior and lateral views from both sides of the chest. Images were transmitted wirelessly using a mobile hotspot device and uploaded into an online image archiving system. Images were interpreted remotely by EMS physicians, and two expert sonographers provided an overread. We assessed agreement between EMS physicians and experts, as well as between chart review-derived ED diagnosis and expert interpretation. We defined 4 a priori hypotheses that would need to be met for the intervention to be considered “feasible.” 34 out of 78 eligible patients had an ultrasound exam completed. Image transmission was successful in 25 cases. The primary reason for not enrolling an otherwise eligible patient was equipment failure (25%), followed by patient acuity and patient refusal (18.2% each). 58.8% of completed scans were deemed uninterpretable upon expert review. Agreement between EMS physicians and experts was low. The predetermined thresholds for feasibility were not met. Paramedic-performed out-of-hospital lung ultrasound for patients with respiratory distress and remote interpretation by EMS physicians did not meet the predetermined thresholds to be considered “feasible” in a real-world environment.