The Use of FAST Scan by Paramedics in Mass-casualty Incidents: A Simulation Study

Introduction: The Focused Abdominal Sonography in Trauma (FAST) scan is used to detect free fluid in the peritoneal cavity, or pericardium, to quickly assess for injuries needing immediate surgical intervention. Mass-casualty incidents (MCIs) are settings where paramedics must make triage decisions in minutes. The Simple Triage and Rapid Transport (START) system is used to prioritize transport. The FAST scan can be added to the triage of critical patients, and may aid in triage. Methods: This was a single-blinded, randomized control trial. Ten paramedics with field experience were trained with an ultrasound machine in the performance of the FAST scan. Two weeks were allowed to pass before testing to simulate the time between training of standard procedures and their implementation. On test day, five peritoneal dialysis patients with instilled dialysis fluid and five matched control patients were placed in a room in a random order where the paramedics performed FAST scans on each patient. The paramedics were assessed by declaring positive or negative for each evaluation, as well as being timed for the total exercise. Results: Of the ninety tests (one paramedic dropped out due to family emergency), the paramedics had a mean accuracy of 60% and median of 62% (range 40%-80%). There was a statistically significant higher false-positive rate of 59% than false-negative rate of 41% (P<.01). Sensitivity was 67% with a specificity of 56%. Average time taken was 1,218 seconds (121.8 seconds per patient) with a range of 735-1,701 seconds and a median of 1,108 seconds. Conclusion: In this simulation study, paramedics had difficulty performing FAST scans with a high degree of accuracy. However, they were more apt to call a patient positive, limiting the likelihood for false-negative triage.