Wireless and satellite transmission of prehospital focused abdominal sonography for trauma

As military operations become smaller and more remote and as humanitarian missions increase, ultrasound technology is emerging as a valuable asset for defining injuries in austere settings. This study evaluated the feasibility of focused abdominal sonography for trauma (FAST) examinations in a field environment with real-time images sent wireless to an antenna and over satellite.

Using a 6-lb SonoSite portable ultrasound device with battery pack, FAST examinations were performed on a healthy volunteer, transferred wireless at distances of 1,000 and 1,500 feet from the receiving antenna using a vest-mounted microwave transmitter, and then redirected over satellite (INMARSAT) to a remote hospital for review by emergency physicians, and a radiologist.

Real-time wireless transmissions at 1,500 feet reliably yielded images without quality or interpretability drop compared with those recorded digitally at the examination site. A 32% reduction in image quality and interpretability was seen with still images and a 42% reduction was noted with cine loops using INMARSAT. The authors did not find the upper distance limit of the wireless transmitter used.

This study suggests 1) that remote FAST examinations are plausible for prehospital care and triage using new-generation portable ultrasound units, 2) that line-of-sight transmission of FAST examinations when compared with on-site images results in no degradation in image quality or interpretability at distances used, 3) that ranges greater than 1,500 feet are feasible for interpretable examinations and therefore line-of-site mass casualty or field triage sites, and 4) that real-time INMARSAT transmission of FAST examinations at 64 kbps may serve a limited role for remote clinical interpretation.