Satellite and mobile wireless transmission of focused assessment with sonography in trauma.

Objectives: Focused assessment with sonography in trauma (FAST) can define life-threatening injuries in austere settings with remote real-time review by experienced physicians. This study evaluates vest-mounted microwave, satellite, and LifeLink communications technology for image clarity and diagnostic accuracy during remote transmission of FAST examinations.

Methods: Using a SonoSite, FAST was obtained on three patients with pericardial and intraperitoneal effusions and two control subjects in a remotely located U.S. Army Combat Support Hospital. A miniature vest-mounted video transmitter attached to the SonoSite sent wireless ultrasound video 20 m to a receiving antenna. The signal was then transferred over VSAT satellite systems at 512 kilobaud per second (kbps), INMARSAT satellite systems at 64 kbps, and over LifeLink on a moving ambulance through a metropolitan wireless traffic-management network. Clarity and absence or presence of effusions were recorded by 15 staff emergency physicians.

Results: Average sensitivity, specificity, and accuracy were 87% (95% confidence interval [CI]=79% to 95%), 85% (95% CI=81% to 89%), and 86% (95% CI=82% to 90%) for the Premier Wireless Vest; 98% (95% CI=97% to 99%), 83% (95% CI=75% to 91%), and 86% (95% CI=82% to 90%) for VSAT; 95% (95% CI=94% to 96%), 70% (95% CI=58% to 82%), and 75% (95% CI=70% to 80%) for INMARSAT; and 82% (95% CI=73% to 91%), 83% (95% CI=74% to 92%), and 82% (95% CI=78% to 86%) for LifeLink with clarity of 3.0 (95% CI=2.7 to 3.3), 2.9 (95% CI=2.6 to 3.2), 1.3 (95% CI=1.2 to 1.4), and 2.1 (95% CI=1.8 to 2.4), respectively.

Conclusions: Accuracy correlated with clarity. Roaming vest transmission of FAST provides interpretable, diagnostic imagery at the distances used in this study. VSAT provided the best clarity and diagnostic value with the lighter, more portable INMARSAT serving a lesser role for remote clinical interpretation. LifeLink performed well, and further infrastructure improvements may increase clarity and accuracy.